Search found 5205 matches

by pythoncoder
Wed Jun 16, 2021 7:23 pm
Forum: Raspberry Pi microcontroller boards
Topic: RPi pico machine.SPI periodic dropout.
Replies: 12
Views: 432

Re: RPi pico machine.SPI periodic dropout.

A possibility is the fact that SPI.read() allocates, which is not allowed in an ISR. This will occur even though you aren't assigning the bytes object to a variable. On most ports allocating in an ISR leads to a traceback, but perhaps the Pico fails silently. If it behaves in this way I would regard...
by pythoncoder
Wed Jun 16, 2021 8:48 am
Forum: Raspberry Pi microcontroller boards
Topic: RPi pico machine.SPI periodic dropout.
Replies: 12
Views: 432

Is the ISR actually running?

OK, this is clearly a different problem from that reported by @dk2jk. You have an easily reproduced test case where the Pico appears not to be responding to an IRQ. There is a doubt in my mind as to whether the ISR is not being called, or if it is being called but the SPI is not responding. To resol...
by pythoncoder
Tue Jun 15, 2021 10:49 am
Forum: Raspberry Pi microcontroller boards
Topic: RPi pico machine.SPI periodic dropout.
Replies: 12
Views: 432

Re: RPi pico machine.SPI periodic dropout.

Yes. This is definitely worth pursuing. It seems very telling that two different candidates are producing such a similar outcome.
by pythoncoder
Tue Jun 15, 2021 10:46 am
Forum: General Discussion and Questions
Topic: Implementing SENT Interface in MicroPython?
Replies: 6
Views: 112

Re: Implementing SENT Interface in MicroPython?

RMT is an ESP32 hardware component so cannot be implemented on STM.
by pythoncoder
Tue Jun 15, 2021 10:10 am
Forum: Raspberry Pi microcontroller boards
Topic: Add if/for/while to PIO asm
Replies: 4
Views: 139

Re: Add if/for/while to PIO asm

... But one practical problem is there are only 32 PIO instruction spaces available and it can be easy to run out once one gets liberal with using block-structured commands. The other is one loses visible determinism, can't simply see how many cycles will have been executed to get to a particular i...
by pythoncoder
Mon Jun 14, 2021 1:42 pm
Forum: General Discussion and Questions
Topic: Saving data on ramdisk before a WDT event
Replies: 4
Views: 94

Re: Saving data on ramdisk before a WDT event

If the ESP32 is crashing, RAM contents will be lost. You could use the network to log data to another machine. In general ramdisks don't make much sense in a microcontroller context because RAM is scarce. If you want to save data in RAM, you're best off saving it in Python objects (lists, dicts or a...
by pythoncoder
Mon Jun 14, 2021 1:26 pm
Forum: General Discussion and Questions
Topic: Job Postings Allowed?
Replies: 2
Views: 84

Re: Job Postings Allowed?

As far as I know (as co-mod) I think this should be OK.
by pythoncoder
Mon Jun 14, 2021 1:25 pm
Forum: General Discussion and Questions
Topic: Implementing SENT Interface in MicroPython?
Replies: 6
Views: 112

Re: Implementing SENT Interface in MicroPython?

17µs is about what I'd expect. This doc explains how to optimise speed, but as you mentioned you may need to use the inline assembler. This can achieve very high performance. It is also possible to write native C modules , however the learning curve for these is similar to that of the assembler (in ...
by pythoncoder
Mon Jun 14, 2021 1:14 pm
Forum: Raspberry Pi microcontroller boards
Topic: RPi pico machine.SPI periodic dropout.
Replies: 12
Views: 432

Re: RPi pico machine.SPI periodic dropout.

I tried this and failed to replicate the fault. To provoke occasional GC I first ran some floating point maths. I then ran a large application which performs periodic GC. In each case the output of the filter was stable. Assuming you guys are running recent firmware I can only conclude that this fau...
by pythoncoder
Mon Jun 14, 2021 9:18 am
Forum: Raspberry Pi microcontroller boards
Topic: RPi pico machine.SPI periodic dropout.
Replies: 12
Views: 432

Re: RPi pico machine.SPI periodic dropout.

Very possible, but I think that if Pyboards had this problem it would have been spotted by now.

A minimal test case might be to run PWM at a fixed frequency with a 50% duty ratio, put the result through an RC filter, and look for glitches with a scope.