Search found 55 matches

by ebike
Thu Jul 21, 2016 6:55 pm
Forum: ESP8266 boards
Topic: micropython frequency measuring
Replies: 22
Views: 9891

Re: micropython frequency measuring

Hi Dave,

Thanks for that ... very interesting, will have a look inti it.

Cheers,
Bernie
by ebike
Tue Jul 19, 2016 11:50 pm
Forum: ESP8266 boards
Topic: micropython frequency measuring
Replies: 22
Views: 9891

Re: micropython frequency measuring

Dang, suspected as much. Back to the drawing board. :cry:

EDIT: .. maybe a better platform would be measuring the input period directly with a RP3 in assembly .... (very off topic for this forum)
by ebike
Tue Jul 19, 2016 6:46 am
Forum: ESP8266 boards
Topic: micropython frequency measuring
Replies: 22
Views: 9891

Re: micropython frequency measuring

Hi, I was thinking along similar lines. My thoughts where to input the frequency to a digital phase comparator (which is one line of Python code) the other input to the phase comparator is the reference frequency (output freq). The output of the phase comparator goes to a biquad digital filter (in P...
by ebike
Tue Jul 19, 2016 4:13 am
Forum: ESP8266 boards
Topic: micropython frequency measuring
Replies: 22
Views: 9891

Re: micropython frequency measuring

Guess I will have to look at another solution.
I can use a DDS chip from Analog devices for output ... but need to find something else for freq input ...

Cheers,
by ebike
Tue Jul 19, 2016 1:08 am
Forum: ESP8266 boards
Topic: micropython frequency measuring
Replies: 22
Views: 9891

Re: micropython frequency measuring

cross-posted .... thanks for the reply ..

I can't divide down as the PLL has to respond to frequency and phase of both reference and input signals
by ebike
Sun Jul 17, 2016 10:33 pm
Forum: ESP8266 boards
Topic: micropython frequency measuring
Replies: 22
Views: 9891

Re: micropython frequency measuring

Hi, I have a similar requirement where I want to periodically measure the freq/width of an input signal. The input signal will vary in frequency between 1 and 10Mhz, and the sampling rate that I do this measurement can be as slow as 10khz .. I presume I could in assembly do a busy wait on an edge, r...
by ebike
Mon Nov 02, 2015 12:53 am
Forum: MicroPython pyboard
Topic: Read ADC using DMA
Replies: 20
Views: 13571

Re: Read ADC using DMA

Excellent stuff. Be great if you implemented the callback or soft interrupt on completion ... that would make it perfect.
(I love event driven code ...no waiting ..) :D
by ebike
Tue Aug 11, 2015 5:26 am
Forum: MicroPython pyboard
Topic: Read ADC using DMA
Replies: 20
Views: 13571

Re: Read ADC using DMA

pythoncoder wrote:
I also have a filter that I could easily re-write in assembly
I assume you've seen my FIR filters in assembler https://github.com/peterhinch/micropython-filters.git
Thanks, had not seen those ..
by ebike
Sun Aug 09, 2015 7:45 am
Forum: MicroPython pyboard
Topic: Read ADC using DMA
Replies: 20
Views: 13571

Re: Read ADC using DMA

I think @manitou is suggesting that acquiring data at a high rate may be pointless if Python can't subsequently process it at the same rate. Although you might be able to implement a fast decimation filter using the inline assembler to reduce the data rate to a more manageable level. On the subject...
by ebike
Sat Aug 08, 2015 8:22 pm
Forum: MicroPython pyboard
Topic: Read ADC using DMA
Replies: 20
Views: 13571

Re: Read ADC using DMA

I haven't tried any of this, and such one-off asynchronous solutions would probably require that you hack the firmware. . Yes, I could hack the firmware, but I thought one of the aims of this forum was to give the maintainers of microPython, some feedback on customer use, and if more people want a ...