MicroPython Forum

Micropython/circuitpython benchmarks on teensy 4 and others
https://forum.pjrc.com/threads/59040-Ci ... post226210

OK, i built and uploaded the micropython to my Teensy4 and got a /dev/ttyACM0 REPL. But no "pop up" USB drive ... is there a way import .py files ? rebuild with the .py files in some special folder or ? I've got some comparative numbers of micropython and circuitpython on a few different MCUs, see h...

Update. Working in C++ on mbed F446RE ( STM32F446xx cortex-m4 @180mhz, hardware float) with the same simple minded CRC hardware as pyboard, I figured out how to do CRC on 32-bit words so that test vector results were good. You have to reverse the bits of the input words, and the final output CRC ha...

Ok, I don't have timing issues for now, so I might try to compile it with DMA one day just to see :) I'll take a look on the HAL, tahnks I did some SPI DMA experiments on CC3200 (launchpad, wipy's are hard to come by in the US). With the SPI clock at 20MHz, the 32-bit SPI DMA runs at 17.2 mbs (1000...

We have developed a new 1-wire driver that works with the latest version of the pyboard firmware as well as the WiPy. The slimmed-down onewire.py looks good. For visual comparison, here is logic analyzer with new onewire onewire1.png The low pulse-width at 168mhz is 5.875us. At 84mhz, the low pulse...

ADC with DMA hack OK, I finally got around to hacking adc.c to use DMA to read the ADC. As above we'll do 10,000 samples. >>> import pyb >>> import array >>> adc = pyb.ADC('X1') >>> buf = array.array('H', bytearray(20000)) >>> t1=pyb.micros(); n=adc.read_timed(buf,2000000); t2=pyb.micros() >>> t2-t...

Here is snapshot of analyzer with ow.write_byte(0xa5) onewire.png The critical timing is that writing a 1-bit is supposed to start with a low pulse of < 15 us. At 168mhz, the python low pulse is 15.25us. The spec says the receiver sampling window is 30us, so the one-wire device will read the value s...

I need to do some tests with the analyzer, but looking at the one-wire spec and then at onewire.py, it appears that in addition to pyb.udelay(), the driver is trying to take into account the delay of each micropython statement (say about 5us) in order to arrive at the cumulative delay expected by th...

pagano.paganino wrote: USART2 is on 84MHz for set to 4MHz is correct set prescaler to 21?

As I read chapter 7 of ref manual, USART2 is on APB1 which runs at 42MHz. you could verify your 4MHz with scope or analyzer.

if you don't require asynchronous ADC acquisition (DMA), i think that you could run the ADC in continuous mode, and the C firmware could test EOC and save the ADC values before the next sample is ready. Thus you would be acquiring the data as fast as the ADC samples became available. I plan to do s...