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Re: Starting/stopping processes dynamically?

Tue, 21 May 2013 16:55:40 GMT

Replies: 5
Views: 169
Last Post By: segher ON: Tue May 21, 2013 4:55 pm
Topic By: segher ON: Tue May 21, 2013 4:55 pm
Hi Christian,

I think you would be best off if you made the process running
on each node an independent program. That is, if there is an
xcore on every node; is there?

Re: Open source mixing console

Tue, 21 May 2013 15:49:26 GMT

Replies: 6
Views: 275
Last Post By: fullm3tal1991 ON: Tue May 21, 2013 3:49 pm
Topic By: fullm3tal1991 ON: Tue May 21, 2013 3:49 pm

franksanderdo wrote:

Hi Ho,

may I ask which DACs / ADCs you are using?

Regards
Frank

the used codec is Cirrus Logic® CS42448. It's the original codec of the audio usb 2.0 MC.
In the futur we may build our own card and change the codec, but right now we will continue with the CS codec.

Re: Starting/stopping processes dynamically?

Tue, 21 May 2013 16:55:40 GMT

Replies: 5
Views: 169
Last Post By: segher ON: Tue May 21, 2013 4:55 pm
Topic By: Treczoks ON: Tue May 21, 2013 9:18 am
Hi, Frank!

Thanks for answering!

franksanderdo wrote:

I would have the Coordinator just giving the information "Following Link Lost" to the work horse. with that it knows it does not have to listen there for Data any more.
If Connect Sync is done by the coordinator (which I would think so) after sync is done the Coordinaor informs the MII about the synced linked and the MII can (re)start listening to the data.

Theoretically, yes. BUT: My workhorses timing is so tight that there is probably no time left for error checking, i.e. They just run and suddenly they are stuck in the middle of dealing with a frame.
A re-start of the workhorse implies a certain build-up: resetting the PHY, waiting for end of negotiation (if it ever comes, the last unit will be stuck here forever), initiating contact and getting things in sync, and, finally, pushing data in an endless loop. So, killing and re-starting the workhorse makes perfectly sense.

franksanderdo wrote:

To think deeper into that I have a question first:
You said that it is possible that some body breaks the chain at any place.
Shall it be automatically 2 chains then? Something like:

No, there is only one running chain. There is a master device at the head of the chain, which also supplies the power and the overall system synchronisation. You can attach units to this master device in a daisy-chain configuration. Each unit first synchronises with its previous unit upon reboot, and then forwards this timing down the chain. If a sub-chain is seperated, it also looses power, and therefor will reboot if it is reattached to a working chain.
This works perfectly well with our proprietary (but slower) bus with up to several hundred devices in a chain. As we cannot speed up our own protocol where I am more or less doing the PHY in software without raising the parts prices into astronomical regions, we thought of using a common-as-muck, off-the-shelf ethernet PHY to the drudge work. So we are basically abusing the PHY for our own frames, no MAC addresses, no frame types, no switches, just two pairs and power connecting the devices.

Yours, Christian

Re: USB to SDIF inerface

Mon, 20 May 2013 09:25:30 GMT

Replies: 11
Views: 555
Last Post By: ghmfranken ON: Mon May 20, 2013 9:25 am
Topic By: ghmfranken ON: Mon May 20, 2013 9:25 am

Ross wrote:

DSD over S/PDIF, sure it can be done on an XMOS chip..

I'm actually halfway through a DSD implementation, it would be pretty easy to output DSD data over S/PDIF.

Why would you want to do this though?

@Ross: I am working on a project here on XCore (http://www.xcore.com/projects/open-sour ... d-over-pcm]). My next challenge is to implement DSD output using the reference software. So I read your comment with great interest. Can you share your DSD implementation and is it based on the reference software (or easy too implement in the reference software)?

Re: Is there a way to stop the compiler optimising out code?

Sun, 19 May 2013 09:24:33 GMT

Replies: 3
Views: 150
Last Post By: Heater ON: Sun May 19, 2013 9:24 am
Topic By: Heater ON: Sun May 19, 2013 9:24 am
Clive,

I would suggest that if the use of optimization upsets the timing of your code and causes it to no longer work correctly for you then you have a problem in your code.

It sounds to me as if you are using "dead code" to create some kind of delay to get the some timing right. When that dead code is optimized away the timing goes wrong.

This is not a good way to do things. As you see it is fragile. Given all the features of these devices to handle time there are better, more robust, ways to do this.

Re: Open source mixing console

Tue, 21 May 2013 15:49:26 GMT

Replies: 6
Views: 275
Last Post By: fullm3tal1991 ON: Tue May 21, 2013 3:49 pm
Topic By: franksanderdo ON: Sun May 19, 2013 8:40 am
Hi Ho,

may I ask which DACs / ADCs you are using?

Regards
Frank

Re: Starting/stopping processes dynamically?

Tue, 21 May 2013 16:55:40 GMT

Replies: 5
Views: 169
Last Post By: segher ON: Tue May 21, 2013 4:55 pm
Topic By: franksanderdo ON: Sun May 19, 2013 8:23 am
Hi Christian,

as far as I understand your question you are planning to run a "coordinator core (SMI core)" and "work horse cores (MII cores)" and want to know if there are other options ?

I believe to have a coordinator core is not such a bad Idea, but I do not yet see the reason to kill a work horse and then reanimate it just because it has one of two links lost!?

I would have the Coordinator just giving the information "Following Link Lost" to the work horse. with that it knows it does not have to listen there for Data any more.
If Connect Sync is done by the coordinator (which I would think so) after sync is done the Coordinaor informs the MII about the synced linked and the MII can (re)start listening to the data.

To think deeper into that I have a question first:
You said that it is possible that some body breaks the chain at any place.
Shall it be automatically 2 chains then? Something like:

|-> MII <-> MII <-> MII <-> MII <-> MII <-|
gets broken
|-> MII <-> MII <||> MII <-> MII <-> MII <-|
and there for it is after
|-> MII <-> MII <-|
and
|-> MII <-> MII <-> MII <-|

Regards
Frank

Re: Flash programming examples for XK-1A board?

Sat, 18 May 2013 07:31:31 GMT

Replies: 1
Views: 93
Last Post By: Clive ON: Sat May 18, 2013 7:31 am
Topic By: Clive ON: Sat May 18, 2013 7:31 am
In answer to my own question - go to www.github.com and search for 'sw_flash_multiboot_example'. This is a good place to start.

Re: Bidirectional Channels

Fri, 17 May 2013 18:36:32 GMT

Replies: 4
Views: 129
Last Post By: richard ON: Fri May 17, 2013 6:36 pm
Topic By: richard ON: Fri May 17, 2013 6:36 pm

rp181 wrote:

Correct! Another question, when using a select guard for two channel reads, how does one guarentee that one channel will be addressed if data is available?

If you just want to prioritise one case over another then you can use the ordered pragma to specify that earlier cases should be prioritised over later cases (see https://www.xmos.com/node/16662, example code is also be available in the xSOFTip Browser inside the xTIMEcomposer).

Debugging multi-tile application

Fri, 17 May 2013 13:44:40 GMT

Replies: 0
Views: 50
Last Post By: Guest ON: Fri May 17, 2013 1:44 pm
Topic By: Anonymous ON: Fri May 17, 2013 1:44 pm
Hello
I'm new to XMOS.
I use SliceKit with XS1-L16A-128-QF124 chip.
I have no problew with setting breakpoints in xTIMEcomposer in applications without explicitli specified tiles.
But if I try to set a breakpoint in the following test application in f() function,
the application does not stop on the breakpoint.
Moreover, if I try to pause execution manually, IDE hangs until I disconnect USB from XTAG.

Code:

#include <platform.h>
#include <xs1.h>


out port p   = on tile[1]:XS1_PORT_4A;


void f(void) {
   while(1)
   {
      p <: 1;
      p <: 0;
   }
}

int main() {
   par   {
      on tile[1]: {
         f();
      }
   }
}

Am I doing something wrong?