MicroPython Forum (Archive)

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...

pythoncoder wrote:It resulted from my arbitrary choice of LED 4 for testing and it works as expected with other LED's.

Ahhhh, interesting. LED4's PWM period is 10ms. QED

Have you discovered anything?

I know I should try this myself ... but what happens if you use udelay() instead of delay()? delay() uses sleep mode (WFI) to pass the time, udelay() is a spin-wait ...

At the following https://github.com/manitou48/pyboard/tree/master/IRremote are classes for an IR transmitter and receiver for Sony. One timer is used for the 40khz-PWM IR transmission, driving an IR LED. A second timer captures the rise and fall of the IR receiver (e.g. TL1838 or GP1UX311QS). Since ...

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 so...

The ADC DMA hardware has a circular buffer option. You could provide a buffer and start the continuously running ADC, and then read the buffer (as it is being continuously updated) at your leisure. You could also be notified (you'd need a callback) or poll the EOC bit to see if a cycle through your ...

I have improved the ADC.read_timed() function so that you can go up to about 750kHz sample rate while retaining precision (with 12 bit resolution, 15 cycle conversion time). The problem was that the ADC was being turned off and then back on between each sample! So now it's just turned on at the sta...