SATISH KASHYAP

DC Motor Control and PWM - Unit 17 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-27T02:42:00.003+05:30

SECTION 17.1: RELAYS AND OPTOISOLATORS

1. Give one application where would you use a relay.

2. Why do we place a driver between the microcontroller and the relay?

3. What is an NC relay?

4. Why are relays that use coils called electromechanical relays?

5. What is the advantage of a solid-state relay over EMR?

6. What is the advantage of an optoisolator over an EM relay?

Answers:

1. With a relay we can use a 5 V digital system to control 12 V-120 V devices such as horns and appliances.

2. Since microcontroller I digital outputs lack sufficient current to energize the relay, we need a driver.

3. When the coil is not energized, the contact is closed.

4. When current flows through the coil, a magnetic field is created around the coil, which causes the armature to be attracted to the coil.

5. It is faster and needs less current to get energized.

6. It is smaller and can be connected to the microcontroller directly without a driver.

SECTION 17.2: STEPPER MOTOR INTERFACING

1. Give the 4-step sequence of a stepper motor if we start with 0110.

2. A stepper motor with a step angle of 5 degrees has steps per revolution.

3. Why do we put a driver between the microcontroller and the stepper motor?

Answers:

1. 0110, 0011, 1001, 1100 for clockwise; and 0110, 1100, 1001, 0011 for counterclockwise

2. 72

3. Because the microcontroller pins do not provide sufficient current to drive the stepper motor

SECTION 17.3: DC MOTOR INTERFACING AND PWM

1. True or false. The permanent magnet field DC motor has only two leads for +ve and -ve voltages.

2. True or false. Just like a stepper motor, one can control the exact angle of a DC motor's move.

3. Why do we put a driver between the microcontroller and the DC motor?

4. How do we change a DC motor's rotation direction?

5. What is stall in a DC motor?

6. True or false. PWM allows the control of a DC motor with the same phase, but different amplitude pulses.

7. The RPM rating given for the DC motor is for __________ (no-load, loaded).

Answers:

1. True

2. False

3. Since microcontroller I digital outputs lack sufficient current to drive the DC motor, we need a driver.

4. By reversing the polarity of voltages connected to the leads

5. The DC motor is stalled if the load is beyond what it can handle

6. False

7. No-load

DS12887 RTC Interfacing and Programming - Unit 16 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-27T02:36:00.003+05:30

SECTION 16.1: DS12887 RTC INTERFACING

1. True or false. All of the RAM contents of the DS12887 are nonvolatile.

2. How many bytes of RAM in the DS12887 are set aside for the clock and date?

3. How many bytes of RAM in the DS12887 are set aside for general-purpose applications?

4. True or false. The NV-RAM contents of the DS12887 can last up to 10 years without an external power source.

5. Which pin of the DS12887 is the same as the ALE pin in the 8051?

6. True or false. When the DS12887 is shipped, its oscillator is turned on.

Answers:

1. True

2. 9

3. 114

4. True

5. AS

6. False

SECTION 16.2: DS12887 RTC PROGRAMMING IN C

1. True or false. The time and date are not updated during the initialization of RTC.

2. What address range is used for the time and date?

3. Give the address of the first RAM location belonging to general-purpose applications.

4. Give the C statement to set the month to October.

5. Give the C statement to set the year to 2009.

Answers:

1. True

2. 0-9

3. 0EH (14 in decimal)

4. XBYTE[8]=0xOA;

5. XBYTE[09]=0x09; where the 20 part of 2009 is assumed.

SECTION 16.3: ALARM, SQW, AND IRQ FEATURES OF THE DS12887 CHIP

1. Which bit of register B belongs to the SQW pin?

2. True or false. The IRQ out pin of DS12887 is active low.

3. Which bit of register B belongs to alarm interrupt?

4. Give the address locations for hh:mm:ss of the alarm.

5. If the source of activation for IRQ is alarm, then explain how the IRQ pin is activated.

6. What is the difference between the AF and AIE bits?

7. What is the difference between the PF and PIE bits?

Answers:

1. D3 of D0 - D7

2. True

3. D5

4. Byte addresses of 1, 3, 5

5. If the AIE bit of Reg B is set to 1, then the IRQ pin is activated. This happens due to the AF bit in register C going high when the alarm time and real time values match.

6. The AF bit in register C becomes high when the alarm time and real time values match, while the AIE bit of register B simply allows the AF to be directed to the IRQ pin.

7. The PF bit in register C becomes high when the edge is detected for the periodic interrupt, while the PIE bit of register B simply allows the PF to be directed to the IRQ pin.

Relay, Optoisolator, and Stepper Motor - Unit 15 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-27T02:29:00.004+05:30

SECTION 15.1: PROGRAMMING THE 8255

1. Find the control byte if all ports are inputs.

2. Find the control byte for PC = in, PB = out, and PA = out.

3. True or false. To avoid aliases, we must decode addresses A0 - A15.

4. Can 86H be the base address for port A of the 8255?

5. Why do we use the MOVX instruction to access the ports of the 8255?

Answers:

1. 9BH

2. 89H

3. True

4. It cannot since we must have Al = 0 and AO = 0 for the base address.

5. The MOVX instruction allows access to external memory and 8255 is mapped as memory-mapped I/0.

SECTION 15.2: 8255 INTERFACING

1. Modify the stepper motor program to turn counterclockwise.

2. True or false. In programming the LCD via an 8255 (without checking the busy flag), port A is always an output port.

3. True or false. In the LCD connection to the 8255, we must have a long delay before issuing the next data if we are not checking the busy flag.

Answers:

1. "RR A" is changed to "RL A".

2. True

3. True

8051 Interfacing to External Memory - Unit 14 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-27T02:25:00.001+05:30

SECTION 14.1: SEMICONDUCTOR MEMORY

1. The speed of semiconductor memory is in the range of

(a) microseconds (b) milliseconds

2. Find the organization and chip capacity for each ROM with the indicated number of address and data pins.

(a) 14 address, 8 data (b) 16 address, 8 data (c) 12 address, 8 data

3. Find the organization and chip capacity for each RAM with the indicated number of address and data pins.

(a) 11 address, 1 data SRAM (b) 13 address, 4 data SRAM

(e) 9 address, 1 data DRAM (f) 9 address, 4 data DRAM

4. Find the capacity and number of pins set aside for address and data for memory chips with the following organizations.

(a) 16Kx4 SRAM (b) 32Kx8 EPROM (c) lMxl DRAM

(d) 256Kx4 SRAM (e) 64Kx8 EEPROM (f) 1Mx4 DRAM

5. Which of the following is (are) volatile memory?

(a) EEPROM (b) SRAM (c) DRAM (d) NV-RAM

Answers:

1. c

2. (a) 16Kx8, 128K bits ( b) 64Kx8, 512K (c) 4Kx8, 32K

3. (a) 2Kxl, 2K bits (b) 8Kx4, 32K (c) 128Kx8, lM

(d) 64Kx4, 256K (e) 256Kxl, 256K (f) 256Kx4, lM

4. (a) 64K bits, 14 address, and 4 data (b) 256K, 15 address, and 8 data

(e) 512K, 16 address, and 8 data (f) 4M, 10 address, and 4 data

5. b, c

SECTION 14.2: MEMORY ADDRESS DECODING

1. A given memory block uses addresses 4000H - 7FFFH. How many K bytes is this memory block?

2. The 74138 is a(n) ______ by ______ decoder.

3. In the 74138 give the status of G2A and G2B for the chip to be enabled.

4. In the 74138 give the status of Gl for the chip to be enabled.

5. In Example 14-6, what is the range of addresses assigned to Y5?

Answers:

1. 16K bytes

2. 3, 8

3. Both must be low.

4. Gl must be high.

5. 5000H- 5FFFH

SECTION 14.3: 8031/51 INTERFACING WITH EXTERNAL ROM

1. If EA= GND, indicate from what source the program code is fetched.

2. If EA = Vcc' indicate from what source the program code is fetched.

3. Which port of the 8051 is used for address/ data multiplexing?

4. Which port of the 8051 provides D0 - D7?

5. Which port of the 8051 provides A0 - A7?

6. Which port of the 8051 provides A8 - A15?

7. True or false. In accessing externally stored program code, the PSEN signal is always activated.

Answers:

1. From external ROM (that is off-chip)

2. From internal ROM (that is on-chip)

3. P0

4. P0

5. P0

6. P2

7. True

SECTION 14.4: 8051 DATA MEMORY SPACE

1. The 8051 has a total of _______ bytes of memory space for both program code and data.

2. All the data memory space of the 8051 is ___________ (internal, external).

3. True or false. In the 8051, program code must be read-only memory.

4. True or false. In the 8051, data memory can be read or write memory.

5. Explain the role of pins PSEN, RD, and WR in accessing external memory.

6. True or false. Every 8051 chip comes with lKB of SRAM.

7. True or false. Upon reset, access to the lKB SRAM of the DS89C4x0 is blocked.

Answers:

1. 128K

2. External

3. True

4. True

5. Only PSEN is used to access external ROM containing program code, but when accessing external data memory we must use RD and WR signals. In other words, RD and WR are only for external data memory and are never used for external program ROM.

6. False

7. True

ADC, DAC, and Sensor Interfacing - Unit 13 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-26T16:41:00.002+05:30

SECTION 13.1: PARALLEL AND SERIAL ADC

1. In the ADC0804, the INTR signal is an ______ (input, output).

2. In the ADC0804, to begin conversion, send a(n) pulse to pin_______.

3. Which pin of the ADC0804 indicates end-of-conversion?

4. Both the ADC0804 and ADCOSOS/0809 are ________ -bit converters.

5. Indicate the direction (out, in) for each of the following pins of the ADCOSOS/0809.

(a) A, B, C (b) SC (c) EOC

6. In the ADC0848, the INTR signal is an _______ (input, output).

7. In the ADC0848, to begin conversion, send a(n) ______ pulse to ________

8. Which pin of the ADC0848 indicates end-of-conversion?

9. The ADC0848 is a(an) _______ -bit converter.

10. True or false. While the ADC0848 has 8 pins for Dout, the MAX1112 has only one Dout pin.

11. Indicate the number of analog input channels for each of the following ADC chips.

(a) ADC0804 (b) ADC0848 (c) MAX1112

12. Explain how to select analog input channel for the MAXl 112.

Answers:

1. Output

2. L-to-H, WR

3. INTR

4. 8

5. (a) all in (b) in (c) out

6. Output

7. L-to-H, WR

8. INTR

9. 8

10. True

11. (a) 1 (b) 8 (c) 8

12. We send the control byte to the DIN pin one bit at a time.

SECTION 13.2: DAC INTERFACING

1. In a DAC, input is ___________ (digital, analog) and output is _______ (digital, analog).

2. In an ADC, input is ___________ (digital, analog) and output is ________ (digital, analog).

3. DAC0808 is a(an) _______ -bit D-to-A converter.

4. (a) The output of DAC0808 is in ___________ (current, voltage).

(b) True or false. The output of DAC0808 is ideal to drive a motor.

Answers:

1. Digital, analog.

2. In ADC the input is analog, the output is digital.

3. 8

4. (a) current (b) true

SECTION 13.3: SENSOR INTERFACING AND SIGNAL CONDITIONING

1. True or false. The transducer must be connected to signal conditioning circuitry before it is sent to the ADC.

2. The LM35 provides m V for each degree of (Fahrenheit, Celsius) temperature.

3. The LM34 provides m V for each degree of (Fahrenheit, Celsius) temperature.

4. Why do we set the

V,ef of ADC0848 to 2.56 V if the analog input is connected to the LM35?

5. In Question 4, what is the temperature if the ADC output is 0011 1001?

Answers:

1. True

2. 10, Celsius.

3. 10, Fahrenheit.

4. Since ADC0848 is an 8-bit ADC, it gives us 256 steps, and 2.56 V /256 = 10 mV. LM35 produces 10 m V for each degree of temperature which matches the ADC's step size.

5. 00111001 = 57, which indicates it is 57 degrees.

LCD and Keyboard Interfacing in 8051 - Unit 12 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-26T16:27:00.002+05:30

SECTION 12.1: LCD INTERFACING

1. The RS pin is an __________ (input, output) pin for the LCD.

2. The E pin is an ____________ (input, output) pin for the LCD.

3. The E pin requires an _____________ (H-to-L, L-to-H) pulse to latch in information at the data pins of the LCD.

4. For the LCD to recognize information at the data pins as data, RS must be set to ____________ (high, low).

5. Give the command codes for line 1, first character, and line 2, first character.

Answers:

1. Input

2. Input

3. H-to-L

4. High

5. 80H and C0H

SECTION 12.2: KEYBOARD INTERFACING

1. True or false. To see if any key is pressed, all rows are grounded.

2. If D3 - DO= 0111 is the data read from the columns, which column does the pressed key belong to?

3. True or false. Key press detection and key identification require two different processes.

4. In Figure 12-6, if the rows are D3 - DO= 1110 and the columns are D3 - DO= 1110, which key is pressed?

5. True or false. To identify the pressed key, one row at a time is grounded.

Answers:

1. True

2. Column3

3. True

4. 0

5. True

8051 Interrupts Programming in Assembly and C - Unit 11 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-26T15:45:00.001+05:30

SECTION 11. l: 8051 INTERRUPTS

1. Of the interrupt and polling methods, which one avoids tying down the microcontroller?

2. Besides reset, how many interrupts do we have in the 8051?

3. In the 8051, what memory area is assigned to the interrupt vector table? Can the programmer change the memory space assigned to the table?

4. What are the contents of register IE upon reset, and what do these contents mean?

5. Show the instruction to enable the EX0 and Timer 0 interrupts.

6. Which pin of the 8051 is assigned to the external hardware interrupt INTl?

7. What address in the interrupt vector table is assigned to the INTl and Timer 1 interrupts?

Answers:

1. Interrupts

2. 5

3. Address locations 0000 to 25H. No. They are set when the processor is designed.

4. All Os means that all interrupts are masked, and as a result no interrupts will be responded to by the 8051.

5. MOV IE, #10000011B

6. P3.3, which is pin 13 on the 40-pin DIP package

7. 0013H for INTl and OOlBH for Timer 1

SECTION 11.2: PROGRAMMING TIMER INTERRUPTS

1. True or false. There is only a single interrupt in the interrupt vector table assigned to both Timer 0 and Timer 1.

2. What address in the interrupt vector table is assigned to Timer 0?

3. Which bit of IE belongs to the timer interrupt? Show how both are enabled.

4. Assume that Timer 1 is programmed in mode 2, THl = F5H, and the IE bit for Timer 1 is enabled. Explain how the interrupt for the timer works.

5. True or false. The last two instructions of the ISR for Timer 0 are:

CLR TF0

RETI

Answers:

1. False. There is an interrupt for each of the timers, Timer O and Timer 1.

2. OOOBH

3. Bits Dl and 03 and "MOV IE, # 1 o o o 1 o 1 o B" will enable both of the timer interrupts.

4. After Timer 1 is started with instruction "SETB TRl", the timer will count up from F5H to FFH on its own while the 8051 is executing other tasks. Upon rolling over from FFH to 00, the TFl flag is raised, which will interrupt the8051 in whatever it is doing and force it to jump to memory location 00lBH to execute the ISR belonging to this interrupt.

5. False. There is no need for "CLR TF0" since the RETI instruction does that for us.

SECTION 11.3: PROGRAMMING EXTERNAL HARDWARE INTERRUPTS

1. True or false. There is a single interrupt in the interrupt vector table assigned to both external hardware interrupts

IT0 and ITl.

2. What address in the interrupt vector table is assigned to INT0 and INTl? How about the pin numbers on port 3?

3. Which bit of IE belongs to the external hardware interrupts? Show how both are enabled.

4. Assume that the IE bit for the external hardware interrupt EXl is enabled and is active low. Explain how this interrupt works when it is activated.

5. True or false. Upon reset, the external hardware interrupt is low-level triggered.

6. In Question 5, how do we make sure that a single interrupt is not recognized as multiple interrupts?

7. True or false. The last two instructions of the ISR for INT0 are:

CLR TCON.1

RETI

8. Explain the role that each of the two bits TCON.0 and TCON.2 play in the execution of external interrupt 0.

Answers:

1. False. There is an interrupt for each of the external hardware interrupts of INT0 and INTl.

2. 0003H and 0013H. The pins numbered 12 (P3.2) and 13 (P3.3) on the DIP package.

3. Bits D0 and D2 and "MOV IE, #10000101B" will enable both of the external hardware interrupts.

4. Upon application of a low pulse (4 machine cycles wide) to pin P3.3, the 8051 is interrupted in whatever it is doing and jumps to ROM location 0013H to execute the ISR.

5. True

6. Make sure that the low pulse applied to pin INTl is no wider than 4 machine cycles. Or, make sure that the INTl pin is brought back to high by the time the 8051 executes the RETI instruction in the ISR.

7. False. There is no need for the "CLR TCON. 0" since the RETI instruction does that for us.

8. TCON.0 is set to high to make INTO an edge-triggered interrupt. If INT0 is edge-triggered (that is, TCON.0 is set), whenever a high-to-low pulse is applied to the INTO pin it is captured (latched) and kept by the TCON.2 bit by making TCON.2 high. While the ISR for INT0 is being serviced, TCON.2 stays high no matter how many times an H-to-L pulse is applied to pin INT0. Upon the execution of the last instruction of the ISR, which is RETI, the TCON.2 bit is cleared, indicating that the INTO pin can respond to another interrupt.

SECTION 11.4: PROGRAMMING THE SERIAL COMMUNICATION INTERRUPT

1. True or false. There is a single interrupt in the interrupt vector table assigned to both the TI and RI interrupts.

2. What address in the interrupt vector table is assigned to the serial interrupt?

3. Which bit of the IE register belongs to the serial interrupt? Show how it is enabled.

4. Assume that the IE bit for the serial interrupt is enabled. Explain how this interrupt gets activated and also explain its actions upon activation.

5. True or false. Upon reset, the serial interrupt is active and ready to go.

6. True or false. The last two instructions of the ISR for the receive interrupt are:

CLR RI

RETI

7. Answer Question 6 for the send interrupt.

Answers:

1. True. There is only one interrupt for both the transfer and receive.

2. 23H

3. Bit D4 (IE.4) and "MOV IE, # 10010000B" will enable the serial interrupt.

4. The RI (received interrupt) flag is raised when the entire frame of data, including the stop bit, is received. As a result the received byte is delivered to the SBUF register and the 8051 jumps to memory location 0023H to execute the ISR belonging to this interrupt. In the serial COM interrupt service routine, we must save the SBUF contents before it is lost by the incoming data.

5. False

6. True. We must do it since the RETI instruction will not do it for the serial interrupt.

7. CLR TI

RETI

SECTION 11.5: INTERRUPT PRIORITY IN THE 8051/52

1. True or false. Upon reset, all interrupts have the same priority.

2. What register keeps track of interrupt priority in the 8051? Is it a bit-addressable register?

3. Which bit of IP belongs to the serial interrupt priority? Show how to assign it the highest priority.

4. Assume that the IP register contains all Os. Explain what happens if both INT0 and INTl are activated at the same time.

5. Explain what happens if a higher-priority interrupt is activated while the 8051 is serving a lower-priority interrupt (that is, executing a lower-priority ISR).

Answers:

1. False. They are assigned priority according to Table 11-3.

2. IP (interrupt priority) register. Yes, it is bit-addressable.

3. Bit D4 (IP.4) and the instruction "MOV IP, #000l0000B" will do it.

4. If both are activated at the same time, INT0 is serviced first since it has a higher priority. After INT0 is serviced, INTl is serviced, assuming that the external interrupts are edge-triggered and H-to-L transitions are latched. In the case of low-level triggered interrupts, if both are activated at the same time, the INTO is serviced first; then after the 8051 has finished servicing the INT0, it scans the INT0 and INTl pins again, and if the INTl pin is still high, it will be serviced.

5. We have an interrupt inside an interrupt, meaning that the lower-priority interrupt is put on hold and the higher one is serviced. After servicing this higher-priority interrupt, the 8051 resumes servicing the lower-priority ISR.

8051 Serial Port Programming in Assembly and C - Unit 10 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-26T08:14:00.004+05:30

SECTION 10.1: BASICS OF SERIAL COMMUNICATION

1. The transfer of data using parallel lines is ________ (faster, slower) but ______(more expensive,less expensive).

2. True or false. Sending data to a printer is duplex.

3. True or false. In full duplex we must have two data lines, one for transfer and one for receive.

4. The start and stop bits are used in the __________(synchronous, asynchronous) method.

5. Assuming that we are transmitting the ASCII letter "E" (0100 0101 in binary) with no parity bit and one stop bit, show the sequence of bits transferred serially.

6. In Question 5, find the overhead due to framing.

7. Calculate the time it takes to transfer 10,000 characters as in Question 5 if we use 9600 bps. What percentage of time is wasted due to overhead?

8. True or false. RS232 is not TTL-compatible.

9. What voltage levels are used for binary O in RS232?

10. True or false. The 8051 has a built-in UART.

11. On the back of x86 PCs, we normally have COM port connectors.

12. The PC COM ports are designated by DOS and Windows as _______ and ____________

Answers:

1. Faster, more expensive

2. False; it is simplex.

3. True

4. Asynchronous

5. With 0100 0101 binary the bits are transmitted in the sequence:

(a) 0 (start bit) (b) 1 (c) 0 (d) 1 (e) 0 (f) 0 (g) 0 (h) 1 (i) 0 (j) 1 (stop bit)

6. 2 bits (one for the start bit and one for the stop bit). Therefore, for each 8-bit character, a total of 10 bits is transferred.

7. 10000 x 10 = 100000 bits total bits transmitted. 100000/9600 = 10.4 seconds; 2/10 = 20°/o.

8. True

9. +3 to +25 V

10. True

11. 2

12. COM 1 and COM 2

SECTION 10.2: 8051 CONNECTION TO RS232

1. True or False: The PC COM port connector is the RS232 type.

2. Which pins of the 8051 are set aside for serial communication, and what are their functions?

3. What are line drivers such as MAX232 used for?

4. MAX232 can support _______ lines for TxD and ______ for RxD.

5. What is the advantage of the MAX233 over the MAX232 chip?

Answers:

1. True

2. Pins 10 and 11. Pin 10 is for TxD and pin 11 for RxD.

3. They are used for converting from RS232 voltage levels to TTL voltage levels and vice versa.

4. 2, 2

5. It does not need the four capacitors that MAX232 must have.

SECTION 10.3: 8051 SERIAL PORT PROGRAMMING IN ASSEMBLY

1. Which timer of the 8051 is used to set the baud rate?

2. If XTAL = 11.0592 MHz, what frequency is used by the timer to set the baud rate?

3. Which mode of the timer is used to set the baud rate?

4. With XTAL = 11.0592 MHz, what value should be loaded into THl to have a 9600 baud rate? Give the answer in

both decimal and hex.

5. To transfer a byte of data serially, it must be placed in register __

6. SCON stands for and it is a(n) -bit register.

7. Which register is used to set the data size and other framing information such as the stop bit?

8. True or false. SCON is a bit-addressable register.

9. When is TI raised?

10 Which register has the SMOD bit, and what is its status when the 8051 is powered up?

Answers:

1. Timer 1

2. 28,800 Hz

3. Mode2

4. -3 or FDH since 28,800 / 3 = 9,600

5. SBUF

6. Serial control, 8

7. SCON

8. False

9. During transfer of stop bit

10. PCON; it is low upon RESET.

SECTION 10.4: PROGRAMMING THE SECOND SERIAL PORT

(All questions refer to the DS89C4x0 chip)

1. Upon reset, which timer is used to set the baud rate for Serial #0 and Serial #1?

2. Which pins are used for the second serial ports?

3. With XTAL = 11.0592 MHz, what value should be loaded into THl to have a 28,800 baud rate? Give the answer in

both decimal and hex.

4. To transfer a byte of data via the second serial port, it must be placed in register _______

5. SCONl refers to _____________and it is a(n) _______ -bit register.

6. Which register is used to set the data size and other framing information such as the stop bit for the second serial port?

Answers:

1. Timer 1

2. Pins Pl.2 and Pl.3

3. -1 of FFH

4. SBUFl

5. Serial Control 1, 8

6. SCONl

SECTION 10.5: SERIAL PORT PROGRAMMING IN C

1. How are the SFR registers accessed in C?

2. True or false. C compilers support the second serial port of the DS89C420 chip.

3. Registers SBUF and SCON are declared in C using the keyword.

Answers:

1. By using the reg51.h file

2. False

3. SFR

8051 Timer Programming in Assembly and C - Unit 9 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-26T06:56:00.000+05:30

SECTION 9.1: PROGRAMMING 8051 TIMERS

1. How many timers do we have in the 8051?

2. Each timer has _______ registers that are ______ bits wide.

3. TMOD register is a(n) ______ bit register.

4. True or false. The TMOD register is a bit-addressable register.

5. Indicate the selection made in the instruction "MOV TMOD, #20H".

6. In mode 1, the counter rolls over when it goes from ______ to ______

7. In mode 2, the counter rolls over when it goes from _______ to ________

8. In the instruction "MOV THl, #-200", find the hex value for the TH register.

9. To get a 2-ms delay, what number should be loaded into TH, TL using mode 1? Assume that XTAL = 11.0592 MHz.

10. To get a 100-µs delay, what number should be loaded into the TH register using mode 2? Assume XTAL = 11.0592 MHz.

Answers:

1. Two

2. 2, 8

3. 8

4. False

5. 0010 0000 indicates Timer 1, mode 2, software start and stop, and using XTAL for frequency.

6. FFFFH to 0000

7. FFH to 00

8. -200 is 38H; therefore, THl = 38H

9. 2 ms/1.085 ms= 1843 = 0733H where TH= 07H and TL= 33H

10. 100 ms/1.085 ms= 92 or 5CH; therefore, TH= 5CH

SECTION 9.2: COUNTER PROGRAMMING

1. Who provides the clock pulses to 8051 timers if C/T = 0?

2. Who provides the clock pulses to 8051 timers if C/T = 1?

3. Does the discussion in Section 9.1 apply to timers if C/T= 1?

4. What must be done to allow P3.4 to be used as an input for Tl, and why?

5. What is the equivalent of the following instruction? "SETB TCON. 6"

Answers:

1. The crystal attached to the 8051

2. The clock source for the timers comes from pins TO and Tl.

3. Yes

4. We must use the instruction "SETB P3. 4" to configure the Tl pin as input, which allows the clocks to come from an external source. This is because all ports are configured as output upon reset.

5. SETB TRl

SECTION 9.3: PROGRAMMING TIMERS 0 AND 1 IN 8051 C

1. Who provides the clock pulses to 8051 timers if C/T = O?

2. Indicate the selection made in the statement "TMOD = Ox20".

3. In mode 1, the counter rolls over when it goes from _____ to ___________

4. In mode 2, the counter rolls over when it goes from ______ to ________

5. In the statement "THl = -200", find the hex value for the TH register.

6. TFO and TFl are part of register ____________

7. In Question 6, is the register bit-addressable?

8. Show how to monitor the TFl flag for high in 8051 C.

Answers:

1. The crystal attached to the 8051

2. Timer 2, mode 2, 8-bit auto reload

3. FFFFH to O

4. FFH to O

5. 38H

6. TMOD

7. Yes

8. while (TF1==0);

8051 Hardware Connection and Intel Hex File - Unit 8 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-26T06:37:00.006+05:30

SECTION 8.1: PIN DESCRIPTION OF THE 8051

1. A given AT89C51 chip has a speed of 16 MHz. What is the range of frequency that can be applied to the XTALl and XTAL2 pins?

2. Which pin is used to inform the 8051 that the on-chip ROM contains the program?

3. Upon power-up, the program counter (PC) has a value of ________

4. Upon power-up, the 8051 fetches the first opcode from ROM address location _______

5. Which 8051 port needs pull-up resistors to function as an I/0 port?

Answers:

1. From Oto 16 MHz, but no more than 16 MHz

2. EA bar

3. PC= 0000

4. 0000

5. Port O

SECTION 8.2: DESIGN AND TEST OF DS89C4x0 TRAINER

1. True or false. The DS89C4x0 is an 8052 chip.

2. Which pin is used for reset?

3. What is the status of the reset pin when it is not activated?

4. What kind of ROM is used in the DS89C4x0 chip?

5. The loader for the DS89C4x0 works with the __________ (serial, parallel) port.

6. Give two reasons that the DS89C4x0 is preferable over 89C51 chips.

7. In the DS89C4x0 Trainer, what is the role of the Prog/Run switch?

8. What is the highest frequency that we can connect to the DS89C420/30?

9. True or false. The DS89C4x0 can download the file into its ROM only if it is in Intel hex file format.

10. Which command is used to erase the contents of ROM in the DS89C4x0 chip?

11. Which command is used to load the ROM in the DS89C4x0 chip?

12. Which command is used to dump the contents of ROM in the DS89C4x0 chip?

Answers:

1. True

2. Pin 9

3. Low

4. Flash

5. Serial

(a) It comes with a loader inside the chip

(b) it has two serial ports

7. The SW allows to load the program or to run it.

8. 33MHz

9. True

10. >K

11. >L

12. >D

SECTION 8.3: EXPLAINING THE INTEL HEX FILE

1. True or false. The Intel hex file uses the checksum byte method to ensure data integrity.

2. The first byte of a line in the Intel hex file represents _________

3. The last byte of a line in the Intel hex file represents __________

4. In the TT field of the Intel hex file, we have 00. What does it indicate?

5. Find the checksum byte for the following values: 22H, 76H, SFH, 8CH, 99H.

6. In Question 5, add all the values and the checksum byte. What do you get?

Answers:

1. True

2. The number of bytes of data in the line

3. Checksum byte

4. 00 means this is not the last line and there are more lines of data to be followed.

5. 22H + 76H + 5FH +SCH+ 99H = 21CH.

Dropping the carries we have lCH and its 2's complement is E4H.

6. 22H + 76H + 5FH + SCH + 99H + E4 = 300H.

Dropping the carries we have 00, which means data is not corrupted

8051 Programming in C - Unit 7 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-24T18:34:00.006+05:30

SECTION 7.1: DATA TYPES AND TIME DELAY IN 8051 C

1. Give the magnitude of the unsigned char and signed char data types.

2. Give the magnitude of the unsigned int and signed int data types.

3. If we are declaring a variable for a person's age, we should use the________ data type.

4. True or false. Using a for loop to create a time delay is not recommended if you want your code be portable to other 8051 versions.

5. Give three factors that can affect the delay size.

Answers:

1. 0 to 255 for unsigned char and-128 to +127 for signed char

2. 0 to 65,535 for unsigned int and -32,768 to +32,767 for signed int

3. Unsigned char

4. True

5. (a) Crystal frequency of 8051 system, (b) 8051 machine cycle timing, and (c) compiler use for 8051 C

SECTION 7.2: I/0 PROGRAMMING IN 8051 C

1. The address of Pl is ____________

2. Write a short program that toggles all bits of P2.

3. Write a short program that toggles only bit Pl.0

4. True or false. The sbit data type is used for both SFR and RAM single-bit addressable locations.

5. True or false. The bit data type is used only for RAM single-bit addressable locations.

Answers:

1. 90H

2. #include <reg51.h>

void main()

{

}

P2 = Ox55;

P2 = OxAA

3. #include <reg51.h>

shit Pl Obit = Pl "0;

void main()

{

}

PlObit = O;

PlObit = 1;

4. False, only to SFR bit

5. True

SECTION 7.3: LOGIC OPERATIONS IN 8051 C

1. Find the content of Pl after the following C code in each case.

(a) Pl=Ox37&0xCA;

(b) Pl=Ox37 ! OxCA;

2. To mask certain bits we must AND them with _____________

3. To set high certain bits we must OR them with ____________

4. Ex-ORing a value with itself results in __________

5. Find the contents of P2 after execution of the following code.

P2=0;

P2=P2 ! 0x99;

P2= ~P2;

Answers:

1. (a) 02 (b) FFH (c) FDH

2. Zeros

3. One

4. All zeros

5. 66H

SECTION 7.4: DATA CONVERSION PROGRAMS IN 8051 C

1. For the following decimal numbers, give the packed BCD and unpacked BCD representations.

(a)15 (b)99

2. Show the binary and hex formats for "76" and its BCD version.

3. 67H in BCD when converted to ASCII is _______H and _______H.

4. Does the following convert unpacked BCD in register A to ASCII?

mydata = 0x09 + 0x30;

5. Why is the use of packed BCD preferable to ASCII?

6. Which one takes more memory space: packed BCD or ASCII?

7. In Question 6, which is more universal?

8. Find the checksum byte for the following values; 22H, 76H, 5FH, 8CH, 99H.

9. To test data integrity, we add them together, including the checksum byte. Then drop the carries. The result must be equal to _______ if the data is not corrupted.

10. An ADC provides an input of 0010 0110. What happens if we output that to the screen?

Answers:

1. (a) 15H = 0001 0101 packed BCD, 0000 0001,0000 0101 unpacked BCD

(b) 99H = 1001 1001 packed BCD, 0000 1001,0000 1001 unpacked BCD

2. 3736H = 00110111 00110110B and in BCD we have 76H = 0111 OllOB

3. 36H,37H

4. Yes, since A = 39H

5. Space savings

6. ASCII

7. ASCII

8. 21CH

9. 00

10. First convert from binary to decimal, then to ASCII, then send to screen.

SECTION 7.5: ACCESSING CODE ROM SPACE IN 8051 C

1. The 8051 has _____ bytes of data RAM, while the 8052 has ________ bytes.

2. The 8051 has _______K bytes of code space and _______K bytes of external data space.

3. True or false. The code space can be used for data but the external data space cannot be used for code.

4. Which space would you use to declare the following values for 8051 C?

(a) the number of days in the week

(b) the number of months in a year

5. In 8051 C, we should not use more than 100 bytes of the RAM data space for variables. Why?

Answers:

1. 128, 256

2. 64K, 64K

3. True

4. (a) data space, (b) data space, (c) RAM space

5. The compiler starts storing variables in code space.

Arithmetic, Logic Instructions, and Programs - Unit 6 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-24T15:19:00.007+05:30

SECTION 6.1: ARITHMETIC INSTRUCTIONS

1. In multiplication of two bytes in the 8051, we must place one byte in register and the other in register

2. In unsigned byte-by-byte multiplication, the product will be placed in register(s) ____________

3. Is this a valid 8051 instruction? "MUL A, Rl". Explain your answer.

4. In byte/byte division, the numerator must be placed in _____ register and the denominator in ___ register

5. In unsigned byte/byte division, the quotient will be placed in ____ register and the remainder in _____ register

6. Is this a valid 8051 instruction? "DIV A, Rl". Explain your answer.

7. The instruction "ADD A, source" places the sum in ____________

8. Why is the following ADD instruction illegal?

"ADD Rl, R2"

9. Rewrite the instruction above in correct form.

10. The instruction "ADDC A, source" places the sum in ________

11. Find the value of the A and CY flags in each of the following.

(a) MOV A, #4FH

ADD A,#OBlH

(b) MOV A, #9CH

ADD A,#63H

12. Show how the CPU would subtract 05H from 43H.

13. If CY= 1, A= 95H, and B = 4FH prior to the execution of "SUBB A, B", what will be the contents of A after the subtraction?

Answers:

1. A, B

2. A, B

3. No. We must use registers A and B for this operation.

4. A, B

5. A, B

6. No. We must use registers A and B for this operation.

7. A, the accumulator

8. No. We must use registers A and B for this operation.

9. MOV A, Rl

ADD A,R2

10. A, the accumulator

11. (a) A= 00 and CY= 1 (b) A= FF and CY= 0

12. 43H = 0100 0011 and -O5H (in 2's complement ) 0100 0011 if both added then

the result is 3EH = 0011 1110

13. A = 95H - 4FH - 1 = 45H

SECTION 6.2: SIGNED NUMBER CONCEPTS AND ARITHMETIC OPERATIONS

1. In an 8-bit operand, bit ___ is used for the sign bit.

2. Convert -16H to its 2's complement representation.

3. The range of byte-sized signed operands is -_____to + ______

4. Show +9 and -9 in binary.

5. Explain the difference between a carry and an overflow.

Answers:

1. D7

2. 16H is 00010110 in binary and its 2's complement is 1110 1010 or -16H = EA in hex.

3. -128 to +127

4. +9 = 00001001 and -9 = 11110111 or F7 in hex.

5. An overflow is a carry into the sign bit (D7), but the carry is a carry out of register (D7).

SECTION 6.3: LOGIC AND COMPARE INSTRUCTIONS

1. Find the content of register A after the following code in each case.

(a) MOV A, #37H

ANL A,#OCAH

(b) MOV A, #37H

ORL A,#OCAH

XRL A,#OCAH

2. To mask certain bits of the accumulator we must ANL it with ______

3. To set certain bits of the accumulator to 1 we must ORL it with _______

4. XRing an operand with itself results in __________

5. True or false. The CJNE instruction alters the contents of its operands.

6. What value must R4 have in order for the following instruction not to jump?

CJNE R4,#53,0VER

7. Find the contents of register A after execution of the following code.

CLR A

ORL A,#99H

CPL A

Answers:

1. (a) 02 (b) FFH (c) FDH

2. Zeros

3. One

4. All zeros

5. False

6. #53

7. 66H

SECTION 6.4: ROTATE INSTRUCTION AND DATA SERIALIZATION

1. What is the value of register A after each of the following instructions?

MOV A, #25H

RR A

2. What is the value of register A after each of the following instructions?

MOV A, #A2H

RL A

3. What is the value of register A after each of the following instructions?

CLR A

SETB C

RRC A

SETB C

RRC A

4. Why does "RLC Rl" give an error in the 8051?

5. What is in register A after the execution of the following code?

MOV A, #85H

SWAP A

ANL A,#OFOH

6. Find the status of the CY flag after the following code.

CLR A

ADD A, #OFFH

JNC OVER

CPL C

OVER:

7. Find the status of the CY flag after the following code.

OVER:

CLR C

JNC OVER

SETB C

8. Find the status of the CY flag after the following code.

OVER:

CLR C

JC OVER

CPL C

9. Show how to save the status of P2.7 in RAM bit location 31.

10. Show how to move the status of RAM bit location 09 to Pl.4.

Answers:

1. 52H

2. 2AH

3. COH

4. Because all the rotate instructions work with the accumulator only

5. SOH

6. CY= 0

7. CY= 1

8. CY= 1

9. MOV C, P2. 7 ; save status of P2. 7 on CY

MOV 31,C ;save carry in RAM bit location 06

10. MOV C, 9 ;save status of RAM bit 09 in CY

MOV Pl.4,C ;save carry in Pl.4

SECTION 6.5: BCD, ASCII, AND OTHER APPLICATION PROGRAMS

1. For the following decimal numbers, give the packed BCD and unpacked BCD representations.

(a)lS (b)99

2. Show the binary and hex formats for "76" and its BCD version.

3. Does the register A have BCD data after the following instruction is executed?

MOV A,#54

4. 67H in BCD when converted to ASCII is H and H.

5. Does the following convert unpacked BCD in register A to ASCII?

MOV A,#09

ADD A,#30H

6. The checksum byte method is used to test data integrity in (RAM, ROM).

7. Find the checksum byte for the following hex values: 88H, 99H, AAH, BBH, CCH, DDH

8. True or false. If we add all the bytes, including

Answers:

1. (a) 15H = 0001 0101 packed BCD, 0000 0001,0000 0101 unpacked BCD

(b) 99H = 10011001 packed BCD, 00001001,0000 1001 unpacked BCD

2. 3736H = 00110111 00110110B and in BCD we have 76H = 0111 OllOB

3. No. We need to write it 54H (with the H) or 01010100B to make it in BCD. The value 54 without the "H" is interpreted as 36H by the assembler.

4. 36H,37H

5. Yes, since A= 39H

6. ROM

7. 88H + 99H + AAH + BBH + CCH + DDH = 42FH. Dropping the carries we have 2FH, and its 2's complement is DlH.

8. False

8051 Addressing Modes - Unit 5 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-24T15:01:00.007+05:30

SECTION 5.1: IMMEDIATE AND REGISTER ADDRESSING MODES

1. Can the programmer of a microcontroller make up new addressing modes?

2. Show the instruction to load 1000 0000 (binary) into R3.

3. Why is the following invalid?

"MOV R2, DPTR"

4. True or false. DPTR is a 16-bit register that is also accessible in low-byte and high-byte formats.

5. Is the PC (program counter) also available in low-byte and high-byte formats?

Answers:

1. No

2. MOV R3,#10000000B

3. Source and destination registers' sizes do not match.

4. True

5. No

SECTION 5.2: ACCESSING MEMORY USING VARIOUS ADDRESSING MODES

1. The instruction "MOV A, 40H" uses addressing ________mode. Why?

2. What address is assigned to register R2 of bank O?

3. What address is assigned to register R2 of bank 2?

4. What address is assigned to register A?

5. Which registers are allowed to be used for register indirect addressing mode if the data is in on-chip RAM?

Answers:

1. Direct; because there is no"#" sign

2. 02

3. 12H

4. EOH

5. RO and Rl

SECTION 5.3: BIT ADDRESSES FOR 1/0 AND RAM

1. True or false. All I/0 ports of the 8051 are bit-addressable.

2. True or false. All registers of the 8051 are bit-addressable.

3. True or false. All RAM locations of the 8051 are bit-addressable.

4. Indicate which of the following registers are bit-addressable.

(a) A (b) B (c) R4 (d) PSW (e) R7

5. Of the 128 bytes of RAM in the 8051, how many bytes are bit-addressable? List them.

6. How would you check to see whether bit DO of R3 is high or low?

7. Find out to which byte each of the following bits belongs. Give the address of the RAM byte in hex.

(a) SETB 2 0 (b) CLR 32 (c) SETB 12H (d) SETB 95H (e) SETB OE6H

8. While bit addresses 00 - 7FH belong to _______________ and bit addresses 80 - F7H belong

to _________________

9. True or false. PO, Pl, P2, and P3 are part of SFR.

10. True or false. Register ACC is bit-addressable.

Answers:

1. True

2. False

3. False

4. A, B, and PSW

5. 16 bytes are bit-addressable; they are from byte location 20H to 2FH.

6. MOV A,R3

JNBACC.O

7. For (a), (b), and (c) use Figure 5-1.

(a) RAM byte 22H, bit 04

(b) RAM byte 24H, bit DO

For (d) and (e) use

Figure 5-2. (d) SETB Pl.5 (e) SEIB ACC.6

8. RAM bytes 00 - 20H, special function registers.

9. True

10. True

SECTION 5.4: EXTRA 128-BYTE ON-CHIP RAM IN 8052

1. True or false. The 8052 is an upgraded version of the 8051.

2. True or false. The 8052 has a total of 256 bytes of on-chip RAM in addition to the SFRs.

3. True or false. The extra 128 bytes of RAM in the 8052 is physically the same RAM as the SFR.

4. Give the address for the upper RAM of the 8052.

5. Show how to put value 99H into RAM location F6H of upper RAM in the 8052.

Answers:

1. True

2. True

3. False

4. 80-FFH

5. MOV A, #99H

MOV RO, #OF6H

MOV @RO,A

I/O Port Programming - Unit 4 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-24T14:52:00.003+05:30

SECTION 4.1: 8051 I/0 PROGRAMMING

1. There are a total of ports in the 8051 and each has bits.

2. True or false. All of the 8051 ports can be used for both input and output.

3. Which 8051 ports need pull-up resistors to function as an I/0 port?

4. True or false. Upon power-up, the 1/0 pins are configured as output ports.

5. Show simple statements to send 99H to ports Pl and P2.

Answers:

1. 4, 8.

2. True

3. PO

4. False

5. MOV Pl,#99H

MOVP2,#99H

SECTION 4.2: 1/0 BIT MANIPULATION PROGRAMMING

1. True or false. The instruction "SETB P2. 1" makes pin P2.1 high while leaving other bits of P2 unchanged.

2. Show one way to toggle the pin Pl.7 continuously using 8051 instructions.

3. Using the instruction" JNB P2 . 5, HERE" assumes that bit P2.5 is an (input, output).

4. Write instructions to get the status of P2.7 and put it on P2.0.

5. Write instructions to toggle both bits of Pl.7 and Pl.O continuously.

Answers:

1. True

2. Hl: CPL Pl.7

SJMP Hl

3. Input

4. MOV C,P2.7

MOV P2.0,C

5. Hl: CPL Pl.7

CPL Pl.O

SJMP Hl

Jump, Loop, and Call Instructions - Unit 3 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-24T14:47:00.002+05:30

SECTION 3.1: LOOP AND JUMP INSTRUCTIONS

1. The mnemonic DJNZ stands for _

2. True or false. "DJNZ R5,BACK" combines a decrement and a jump in a single instruction.

3. "JNC HERE" is a -byte instruction.

4. In "JZ NEXT", which register's content is checked to see if it is zero?

5. LJMP is a -byte instruction.

Answers:

1. Decrement and jump if not zero

2. True

3. 2

4. A

5. 3

SECTION 3.2: CALL INSTRUCTIONS

1. What do the mnemonics "LCALL" and" A CALL" stand for?

2. True or false. In the 8051, control can be transferred anywhere within the 64K bytes of code space if using the

LCALL instruction.

3. How does the CPU know where to return to after executing the RET instruction?

4. Describe briefly the function of the RET instruction.

5. The LCALL instruction is a -byte instruction.

Answers:

1. Long CALL and Absolute CALL

2. True

3. The address of where to return is in the stack.

4. Upon executing the RET instruction, the CPU pops off the top two bytes of the stack into the program counter (PC)

5. 3

SECTION 3.3: TIME DELAY FOR VARIOUS 8051 CHIPS

1. True or false. In the 8051, the machine cycle lasts 12 clock cycles of the crystal frequency.

2. The minimum number of machine

cycles needed to execute an 8051 instruction is _

3. For Question 2, what is the maximum number of cycles needed, and for which instructions?

4. Find the machine cycle for a crystal frequency of 12 MHz.

5. Assuming a crystal frequency of 12 MHz, find the time delay associated with the loop section of the following

DELAY subroutine.

DELAY: MOV R3,#100

HERE: NOP

NOP

DJNZ R3 , HERE

RET

6. True or false. In the DS89C420/30, the machine cycle lasts 12 clock cycles of the crystal frequency.

7. Find the machine cycle for a DS89C420/30 if the crystal frequency is 11.0592 MHz.

Answers:

1. True

2. 1

3. MUL and DIV each take 4 machine cycles.

4. 12 MHz I 12 = 1 MHz, and MC= 1/1 MHz= 1 µs.

5. [100(1 + 1 + 1 + 2)] x 1 µs = 500 µs = 0.5 milliseconds.

6. False. It takes 1 clock.

7. 11.0592 MHz/1 = 11.0592 MHz; machine cycle is 1/11.0592 MHz= 0.0904 µs = 90.4 ns

8051 Assembly Language Programming - Unit 2 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-24T14:35:00.010+05:30

Unit - 2: 8051 Assembly Language Programming

SECTION 2.1: INSIDE THE 8051

1. Write the instructions to move value 34H into register A and value 3FH into register B, then add them together.

2. Write the instructions to add the values 16H and CDH. Place the result in register R2.

3. True or false. No value can be moved directly into registers RO - R7.

4. What is the largest hex value that can be moved into an 8-bit register? What is the decimal equivalent of the hex value?

5. The vast majority of registers in 8051 are bits.

Answers:

1. MOV A,#34H

MOVB,#3FH

ADDA,B

2. MOV A,#16H

ADDA,#OCDH

MOVR2,A

3. False

4. FF hex and 255 in decimal

5. 8

SECTION 2.2: INTRODUCTION TO 8051 ASSEMBLY PROGRAMMING

1. What is the purpose of pseudo-instructions?

2. Are translated by the assembler into machine code, whereas are not.

3. (True or False) Assembly language is a high-level language.

4. Which of the following produces opcode?

(a) ADD A,R2

(b) MOV A,#12

(d) SJMP HERE

5. Pseudo-instructions are also called ______________

6. (True or False) Assembler directives are not used by the CPU itself. They are simply a guide to the assembler.

7. In question 4, which one is an assembler directive?

Answers:

1. The real work is

performed by instructions such as MOV and ADD. Pseudo-instructions, also called assembler

directives, instruct the assembler in doing its job.

2. The instruction mnemonics, pseudo-instructions

3. False

4. All except (c)

5. Assembler directive

6. True

7. (c)

SECTION 2.3: ASSEMBLING AND RUNNING AN 8051 PROGRAM

1. True or false. The DOS program EDIT produces an ASCII file.

2. True or false. Generally, the extension of the source file is "asm" or "src".

3. Which of the following files can be produced by the DOS EDIT program?

(a) myprog.asm

(b) myprog.obj

(d) myprog.lst

4. Which of the following files is produced by an 8051 assembler?

(a) myprog.asm

(b) myprog.obj

(d) myprog.lst

5. Which of the following files lists syntax errors?

(a) myprog.asm

(b) myprog.obj

(d) myprog.lst

Answers:

1. True

2. True

3. (a)

4. (b) and (d)

5. (d)

SECTION 2.4: THE PROGRAM COUNTER AND ROM SP ACE IN THE 8051

1. In the 8051, the program counter is bits wide.

2. True or false. Every member of the 8051 family, regardless of the maker, wakes up at memory OOOOH when it is powered up.

3. At what ROM location do we store the first opcode of an 8051 program?

4. The instruction "MOV A, #44H" is a -byte instruction.

5. What is the ROM address space for the 8052 chip?

Answers:

1. 16

2. True

3. OOOOH

4. 2

5. With 8K bytes, we have 8192 (8 x 1024 = 8192) bytes, and the ROM space is 0000 to lFFFH.

SECTION 2.5: 8051 DATA TYPES AND DIRECTIVES

1. The directive is always used for ASCII strings.

2. How many bytes are used by the following?

DATA 1: DB "AMERICA"

3. What is the advantage in using the EQU directive to define a constant value?

4. How many bytes are set aside by each of the following directives?

(a) ASC_DATA: DB "1234"

(b) MY_DATA: DB "ABC1234"

5. State the contents of memory locations 200H - 205H for the following:

ORG 200H MYDATA: DB "ABC123"

Answers:

1. DB

2. 7

3. If the value is to be changed later, it can be done once in one place instead of at every occurrence.

4. (a) 4 bytes (b) 7 bytes

5. This places the ASCII values for each character in memory locations starting at 200H. Notice that all values are in

hex.

200 = (41)

201 = (42)

202 = (43)

203 = (31)

204 = (32)

205 = (33)

SECTION 2.6: 8051 FLAG BITS AND THE PSW REGISTER

1. The flag register in the 8051 is called _

2. What is the size of the flag register in the 8051?

3. Which bits of the PSW register are user-definable?

4. Find the CY and AC flag bits for the following code.

MOVA, #OFFH

ADD A, #01

5. Find the CY and AC flag bits for the following code.

MOVA, #OC2H

ADD A, #3DH

Answers:

1. PSW (program status register)

2. 8 bits

3. 01 and 05, which are referred to as PSW.1 and PSW.5, respectively.

5. Hex: FF + 1 = 100

Binary: 1111 1111 + 1 = 1 0000 0000

This leads to CY = 1 and AC = 1.

Hex C2 + 3D = FF

Binary 1100 0010 + 0011 1101 = 1111 1111

SECTION 2.7: 8051 REGISTER BANKS AND STACK

1. What is the size of the SP register?

2. With each PUSH instruction, the stack pointer register, SP, is (incremented, decremented) by 1.

3. With each POP instruction, the SP is (incremented, decremented) by 1.

4. On power-up, the 8051 uses RAM location as the first location of the stack.

5. On power-up, the 8051 uses bank for registers RO - R7.

6. On power-up, the 8051 uses RAM locations to for registers RO - R7

7. Which register bank is used if we alter RSO and RSl of the PSW by the following two instructions?

SETB PSW.3

SETB PSW.4

8. In Question 7, what RAM locations are used for register RO - R7?

Answers:

1. 8-bit

2. Incremented

3. Decremented

4. 08

5. 0

6. 0-7

7. Register bank 3

8. RAM locations 18H to lFH

The 8051 Microcontrollers - Unit 1 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-23T22:22:00.006+05:30

Unit - 1: The 8051 Microcontrollers

Section 1.1 - MICROCONTROLLERS AND EMBEDDED PROCESSORS

1. Microcontrollers are normally less expensive than Microprocessors (TRUE / FALSE)

2. When comparing a system board based on a microcontroller and a general purpose microprocessor, which one is cheaper?

3. A microcontroller normally has which of the following devices on-chip?

a. RAM

b. ROM

c. I/O

d. All of the above

4. A general purpose microprocessor normally needs which of the following devices to be attached to it?

a. RAM

b. ROM

c. I/O

d. All of the above

5. An Embedded System is also called a dedicated system. Why?

6. What does the term Embedded System mean?

7. Why does having multiple sources of a given product mater?

Answers:

1. TRUE

2. A microcontroller based system

3. D

4. D

5. It is defined since it is dedicated to doing one type of job.

6. Embedded System means that the application and processor are combined into a single system.

7. Having multiple sources for a given part means you are not hostage to one supplier. More importantly, competition among suppliers brings about lower cost for that product.

Section 1.2 - OVERVIEW OF THE 8051 FAMILY

1. Name three features of the 8051.

2. What is the major difference between the 8051 and 8052 microcontrollers?

3. Give the size of RAM in each of the follwoing:

a. 8051

b. 8052

c. 8031

4. Give the size of On-Chip ROM in each of the following:

a. 8051

b. 8052

c. 8031

5. The 8051 is a(an) ___ bit microcontroller.

6. State a major difference between the 8751, the AT89C51 and the DS89C420/430.

7. The DS89C420/430 is really an 8052 chip. (TRUE / FALSE)

8. The DS89C420/430 has a loader embedded to the chip, therefore eliminating the need for ROM burner. (TRUE / FALSE)

9. The DS89C420/430 chip has _____ bytes of On-Chip ROM.

10. The DS89C420/430 chip has _____ bytes of RAM>

Answers:

1. 128 Byres of RAM, 4K Bytes of On-Chip ROM, Four 8 bit I/O ports

2. 8052 is similar to 8051 with extra features like one extra timer, 8K Bytes On-Chip ROM instead of 4K On-Chip ROM

a. 8051 - 128 Bytes of RAM

b. 8052 - 256 Bytes of RAM

c. 8031 - 128 Bytes of RAM

a. 8051 - 4K Bytes

b. 8052 - 8K Bytes

c. 8031 - Zero KBytes

5. 8

6. The main difference is the type of On-Chip ROM.

a. 8751 - UV-EPROM

b. AT89C51 - FLASH ROM

c. DS89C420/430 - FLASH with a LOADER on the Chip

7. TRUE

8. TRUE

9. 16K

10. 256

Introduction to Computing - Unit 0 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

2020-08-23T21:51:00.008+05:30

Unit - 0: Introduction to Computing

Section 0.1 - NUMBERING AND CODING SYSTEMS

1. Why do computers use the binary number system instead of the decimal system?

2. Convert 34 decimal to binary and Hex

3. Convert 110101 binary to Hex and decimal

4. Perform binary addition: 101100 + 101

5. Convert 101100 binary to its 2's complement representation

6. Add Hexa decimal numbers: 36B and F6

7. Subtract in Hexa decimal: 36B - F6

8. Write "80x86 CPUs" in its ASCII code (in Hex form)

Answers:

1. because each bit can have one of two voltage levels: ON and OFF

2. 34 decimal = 100010 binary = 22 Hexadecimal

3. 110101 binary = 35 hexadecimal = 53 decimal

4. 1110001

5. 010100

6. 461

7. 275

8. 38 30 78 38 36 20 43 50 55 73

Section 0.2 - DIGITAL PRIMER

1. The logical operation ___________ gives a 1 output when all inputs are 1.

2. the logical operation ___________ gives a 1 output when 1 or more of its inputs is 1.

3. the lgoical operation ___________ is oftern used to compare if the two inputs have the same value.

4. A __________ gate does not change the logic level of the input.

5. Name a common use for flip-flops

6. An address ________ is used to identify a predetermined binary address.

Answers:

1. AND

2. OR

3. XOR

4. Buffer

5. Storing data

6. Decoder

Section 0.3 - INSIDE THE COMPUTER

1. How many bytes in 24 kilobytes?

2. What does "RAM" stands for? How is it used in computer systems?

3. What does "ROM" stands for? How is it used in computer systems?

4. Why is RAM called "Volatile Memory"?

5. List the three major components of a computer system

6. What does "CPU" stand for? Explain its function in a computer.

7. List the three types of buses found in computer systems and state briefly the purpose of each type of bus.

8. State which of the following is Unidirectional and bi-directional. a. Data bus b. Address bus

9. If the address bus for a given computer has 16 lines, what is the maximum amount of memory it can access?

10. what does "ALU" stand for? what is its purpose?

11. How are registers used in computer systems?

12. What is the purpose of the program counter?

13. What is the purpose of the instruction decoder?

Answers:

1. 24,576

2. Random Access Memory: it is used for temporary storage of programs that the CPU is running, such as the operating system, word processing programs etc...

3. Read Only Memory: it is used for permanent programs such as those that control the keyboard, mouse etc...

4. The contnets are RAM are lost when the computer is powered off.

5. The CPU, Memory and I/O devices

6. Central Processing Unit: it can be considered as the "brain" of the computer, it executes the programs and controls all other devices in the computer.

7. The address bus carries the location (address) needed by the CPU: The data bus carries information in and out of the CPU The control bus is used by the CPU to send signals controlling I/O devices.

8. a. Birectional b. Unidirectional

9. 64KB or 65,536 bytes

10. Arithmetic Logic Unit: it performs all arithmetic and logical operations

11. It is for temporary storage of information

12. It holds the address of the next instruction to be executed

13. It tells the CPU what steps to perform for each instruction

ISRO 2018 Question Paper - Electronics (EC)

2018-04-23T17:26:00.001+05:30

Final Key for TS TRANSCO AE Electrical Exam

2018-03-27T15:16:00.001+05:30

For Question Paper CLICK HERE

Final Key for TS TRANSCO - AE Telecom exam

2018-03-27T15:13:00.000+05:30

for Question paper click here

Complete Solutions for TS TRANSCO 2018 Assistant Engineer ECE AE from ACE Academy

2018-03-21T11:33:00.001+05:30

Complete Solutions from ACE academy - TS Transco 2018 AE - EEE branch

2018-03-21T11:21:00.004+05:30

GATE 2018 Question Papers and Answer Keys (Officially Released by IIT Guwahati)

2018-03-14T11:54:00.000+05:30

GATE 2018 Question Papers and Answer Keys
Aerospace Engineering (AE)	Question Paper	Answer Key
Agricultural Engineering (AG)	Question Paper	Answer Key
Architecture and Planning (AR)	Question Paper	Answer Key
Biotechnology (BT)	Question Paper	Answer Key
Civil Engineering (CE)	Question Paper (CE01) Question Paper (CE02)	Answer Key (CE01) Answer Key (CE02)
Chemical Engineering (CH)	Question Paper	Answer Key
Computer Science and Information Technology (CS)	Question Paper	Answer Key
Chemistry (CY)	Question Paper	Answer Key
Electronics and Communication Engineering (EC)	Question Paper	Answer Key
Electrical Engineering (EE)	Question Paper	Answer Key
Ecology and Evolution (EY)	Question Paper	Answer Key
Geology and Geophysics (GG)	Question Paper	Answer Key
Instrumentation Engineering (IN)	Question Paper	Answer Key
Mathematics (MA)	Question Paper	Answer Key
Mechanical Engineering (ME)	Question Paper (ME01) Question Paper (ME02)	Answer Key (ME01) Answer Key (ME02)
Mining Engineering (MN)	Question Paper	Answer Key
Metallurgical Engineering (MT)	Question Paper	Answer Key
Petroleum Engineering (PE)	Question Paper	Answer Key
Physics (PH)	Question Paper	Answer Key
Production and Industrial Engineering (PI)	Question Paper	Answer Key
Textile Engineering and Fibre Science (TF)	Question Paper	Answer Key

TS Transco Assistant Engineer (AE) - Electrical & Electronics (EEE) Question Paper

2018-03-14T11:42:00.001+05:30

This exam is conducted on 11th Mar 2018 in the Morning session. The exam is bit tough.. those who prepared well can able to attempt, as well a bit lengthy also....those who prepared subject along with mathematics can able to score good marks. For the questions on English grammar and , no separate preparation is needed. We can't expect questions from history of Telangana, how much we prepare...

So i suggest who are preparing for the next time, prepare both subject and mathematics as well.

Have a look at the Question Paper.........

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