MicroPython Forum (Archive)

I'm trying to implement PWM with the help of in-line assembler, on this quest I've kind of decided that it's sanest to minimise the assembler to basic peek and poke and "do the logic"/heavy lifting in uPy. However I'm running into hard-faults, which I *think* I've substantiated shouldn't be occurrin...

Jon, many thanks - I'm trying desperately to avoid C, for various (personal) reasons, but I've had a look through your sample code and it verifies what I've learnt (from Google) needs to be done to setup and control PWM (and substantiated by peering into and manipulating LED 4's associated GPIO and ...

Thanks, I reported the movwt issue ... uPy appears to support a subset of the commands required for these operations i.e. it supports mov and movt ... but the limitations of what it currently exposes come up pretty quickly (particularly in relation to absence of more useful variants of commands that...

*Somewhere* I think I read that micropython implements 31 bit integers, but I can't recall where, is this correct? (recall something about the most significant bit indicating to the gc whether it's a pointer or a number) In pursuit of a temporary PWM fix, via embedded assembler, I am trying to push ...

This mornings work, dumb h-bridge dc motor driver skin and code module;



This afternoons work; inline assembler tutorial and lots of googe'ling ... but no PWM speed control, yet ...

That's so crude and wrong, it's fantastic ... ';o)

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Connecting the DAC direct into a piezo buzzer also works, and is very quiet ;o) Note this thread - http://forum.micropython.org/viewtopic.php?f=6&t=193 - ADC outputs 12bit values, DAC takes a buffer of 8bit values - @pfalcon says that the ADC will just drop the low-byte when writing into a bytearray...

pyb module has a pyb.pwm function, and many of the pyboard pins are circled i.e. indicating support for pwm ... but there's no documentation on micropython.org. pyb.pwm takes two int arguments, and anecdotal evidence points to it being used by pyb.Servo and pyb.LED on LED4, but otherwise it's a bit ...

I guess a generator is a more microPythonic (aka efficient) way of doing it? i.e. >>> def fillbuf(l): ... for i in range(l): yield 0 ... >>> import array >>> buf=array.array('H',fillbuf(10)) >>> buf array('H', [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]) Which could theoretically be appended to the initialiser o...

Ahhh ... prefilling an array seems to work, bingo?! >>> import pyb,array >>> adc=pyb.ADC(pyb.Pin.board.X5) >>> buf=array.array('H') >>> for i in range(10): buf.append(0) ... >>> adc.read_timed(buf,10) 20 >>> buf array('H', [3666, 3664, 3673, 3671, 3671, 3669, 3672, 3671, 3666, 3671]) >>> (X5 wasn't ...