Talk for Vintage Computer Festival Midwest #20 (2025).

A big thank you to MacroFab for manufacturing the boards and sponsoring the video. I also want to thank Unexpected Maker for their noteworthy contribution to the FeatherS3 microcontroller boards, which played an essential role in the video.

This video covers:
– The detailed design process of the sensor Feather Wing.
– My DIY assembly struggles and the rework that followed.
– Turning to MacroFab’s TurnKey assembly services to get the job done right.
– What I discovered about my garden with the help of this project.

For more information, check out this Bald SENSE post on AddOhms.

I have been using the Pico Technology PicoScope 2000A for years. (Here is my older review!) It is an entry-level oscilloscope with 10 MHz bandwidth, 100 megasamples per second sample rate, and 8 kilosample of acquisition memory. Since it is USB-based, it has companion software running on Windows, macOS, and Linux.

PicoScope 7 introduces a significant visual overhaul. It features a highly flexible waveform display area, intuitive control boxes for timebase and trigger systems, and a left panel that holds channels and various functions. Users can customize the panel placement and quick-access buttons for enhanced workflow.

In this video, I demonstrate the software’s features using the 2000A’s built-in arbitrary waveform generator (AWG) to create a 1 kHz sine wave and other digital patterns. The DeepMeasure function, which provides detailed cycle-by-cycle analysis, stands out as a unique capability for in-depth measurement.

A highlight of the video demo is the I3C measurement, where I capture and decode I3C traffic using PicoScope’s free serial decoders. I then use reference waveforms to explain the differences between I2C and I3C protocols.

PicoScope 7 also includes advanced features like history mode, a detailed math editor, and FFT/Spectrum view, making it a versatile tool for engineers. The software is available for download even without hardware, allowing users to explore its features in demo mode.

Python Code

input_string = "Mega IIe"

def string_to_hex_ascii(input_string, set_bit_8=False):
    hex_values = []
    for char in input_string:
        # Get the ASCII value of the character ord() and convert it string
        # representing the hex() value
        #
        # [2:] strips the '0x'

        if (set_bit_8):
            hex_value = (hex(ord(char) | 0x80)).upper() # for Apple II, awww
        else:
            hex_value = (hex(ord(char))).upper()
        
        hex_values.append(hex_value[2:])

    return hex_values

def print_list_with_spaces(input_list):
    # Join the list elements into a single string with spaces in between
    result = ' '.join(map(str, input_list))
    print(result)

def print_og_string_formatted(input_string):
    result = '  '.join(input_string)
    print(result)

# Remind user of string
print("Og  : ", end='')
print_og_string_formatted(input_string)

# As-is ASCII in Hex
hex_values_raw = string_to_hex_ascii(input_string)
print("Raw : ", end='')
print_list_with_spaces(hex_values_raw)

# Hex with 8th bit set
hex_values_8bit = string_to_hex_ascii(input_string, True)
print("8bit: ", end='')
print_list_with_spaces(hex_values_8bit)

Disclaimer: I used ChatGPT to generate an initial script for converting an ASCII string to a list of hex values. Then, I wrote the rest.

Example

The Apple IIe Enhanced ROM has the string Apple //e. It is displayed at the top of the screen during boot. Here is the 7-bit ASCII version and the 8-bit version found in the ROM file at address:

Og  : A  p  p  l  e     /  /  e
Raw : 41 70 70 6C 65 20 2F 2F 65
8bit: C1 F0 F0 EC E5 A0 AF AF E5

Google Slides

Links

• Circuit Break Podcast #434: The Other VCC
• Circuit Break Podcast #141: It Depends MLCCs with James Lewis
• YouTube: Bald Engineer’s Capacitor Videos
• Hioki USA: Unlocking the Secrets of Capacitor Impedance Plots
• Murata: SimSurfing
• Yageo Group / KEMET: K-SIM

The DAS60 is designed for lab and fieldwork. Its built-in battery means you can deploy it in a facility and let it log data. It has built-in ethernet and support for generic Wi-Fi dongles. The computer runs Windows CE and has RealVNC pre-installed. This combination lets you connect remotely to configure the instrument, check its status, or review recorded data.

KansasFest is an Apple II conference. This year, it moved its venue to Springfield, Illinois. The name and the location might seem confusing; however, it was long held in Missouri. So, it is a case of the name sticking for historical reasons.

It was great to be on the show, especially since I recognized everyone from other aspects of the retro community. You can watch the full Retro Repairs RoundUp here.

Hackaday’s Superconference 2023 took place in Pasadena, CA. In addition to talking about the Mega IIe, I hung out with many great people from the electronics hardware community and saw many incredible talks.

You can download my slides from this resource page.

The MCX line of microcontrollers, each with its unique set of features, caters to a wide range of projects. The MCX-A, a general-purpose microcontroller, is ideal for entry-level projects, while the high-performance MCX-N is designed for advanced AI/machine learning tasks. NXP recently started shipping the MCX-N, adding to its versatility and appeal.

The FRDM boards, with their various connection options, provide a high level of flexibility in design. NXP’s inclusion of an onboard simplifies the programming and debugging process, ensuring a smooth development experience. However, I did encounter some issues with the development environment. 

The VS Code install was not smooth, and some of the examples from NXP’s Application Hub would not load. The Eclipse-based MCUXpresso fared slightly better, but it refused to program the MCX-N board for some reason.

With onboard debuggers, versatile connectivity options, and an affordable price range, these boards are an exciting option for any embedded designer.