Search found 10 matches

by whemming
Wed Feb 22, 2017 1:22 am
Forum: ESP32 Arduino
Topic: ADC Sample rate
Replies: 13
Views: 16070

Re: ADC Sample rate

Thanks! That was very helpful. I will run some test and report back.

Regards,

William
by whemming
Tue Feb 21, 2017 8:36 pm
Forum: ESP32 Arduino
Topic: ADC Sample rate
Replies: 13
Views: 16070

Re: ADC Sample rate

One other thing, in my testing it reveals the timer clock runs at 80Mhz, not the CPU clock of 240Mhz. Why is this?


William
by whemming
Tue Feb 21, 2017 8:24 pm
Forum: ESP32 Arduino
Topic: ADC Sample rate
Replies: 13
Views: 16070

Re: ADC Sample rate

I think my issue was with the timer. Not sure why the first timer is off. I try your code when I get a chance. This doesn't time correctly, does not trigger at 9600: timer = timerBegin(3, 1, 1); timerAttachInterrupt(timer, &sample_isr, 1); timerAlarmWrite(timer, 13333, true);// 9600 timerAlarmEnable...
by whemming
Sat Feb 18, 2017 7:34 pm
Forum: ESP32 Arduino
Topic: ADC Sample rate
Replies: 13
Views: 16070

Re: ADC Sample rate

I just read this post about the WiPy2 which is a ESP32 based python dev board. It states a 21.3k sps actual tested rate. So makes me thing the 6k rate is based on firmware, not hardware.

https://forum.pycom.io/topic/170/lopy-w ... formance/8

William
by whemming
Sat Feb 18, 2017 7:24 pm
Forum: ESP32 Arduino
Topic: ADC Sample rate
Replies: 13
Views: 16070

Re: ADC Sample rate

A post on this thread talking about ADC in connection with the ESP-IDF APIs mentions that the max sample frequency is 6KHz ... or a maximum sps of 6000. Do you have a project in mind that needs higher sample rates than that? I already found my answer in another thread. The other thread was asking a...
by whemming
Fri Feb 17, 2017 4:49 pm
Forum: ESP32 Arduino
Topic: Timer ISR
Replies: 5
Views: 6985

Re: Timer ISR

The maximum sampling frequency of 6000 times a second can be found here ... https://esp32.com/viewtopic.php?f=2&t=1075 If I may ask, what kind of project needs to sample an analog input at more than 6000 times a second? I'm decoding AFSK1200. I take 8 samples per AFSK bit. I have this working fine ...
by whemming
Fri Feb 17, 2017 3:57 pm
Forum: ESP32 Arduino
Topic: ADC Sample rate
Replies: 13
Views: 16070

ADC Sample rate

Anyone know the MAX ADC sample rate? I'm attempting to sample the ADC at 9600 sps, I'm using the analogRead(); function. Is there a faster way? Or is the ADC just too slow for this sample rate?

Thanks!

William
by whemming
Fri Feb 17, 2017 12:48 pm
Forum: ESP32 Arduino
Topic: Timer ISR
Replies: 5
Views: 6985

Re: Timer ISR

I'm going to close this topic, as I got my answer elsewhere. I will open a new topic on the ADC sample rate discussion. Here is an example timer sketch, for others hw_timer_t * timer = NULL; void onTimer(){ static unsigned int counter = 1; Serial.print("onTimer "); Serial.print(counter); Serial.prin...
by whemming
Fri Feb 17, 2017 4:29 am
Forum: ESP32 Arduino
Topic: Timer ISR
Replies: 5
Views: 6985

Re: Timer ISR

Max ADC sample rate has been quoted at 6khz Where is this documented? Do you have a link? That is a pretty sad rate if true. My whole point of using the ESP32 was so I wouldn't have to use an external ADC, as I currently do on the esp8266. I would still like to figure out the ISR, as SPI ADC's run ...
by whemming
Fri Feb 17, 2017 3:22 am
Forum: ESP32 Arduino
Topic: Timer ISR
Replies: 5
Views: 6985

Timer ISR

Are there any examples of timer ISR? I need to sample the adc a a specified rate (9600 times a sec). I would like to attachinterrupt to an ISR. Here is what I'm doing in the ESP8266. How do I do this in the ESP32? void timer_init(void) { timer1_isr_init(); timer1_attachInterrupt(sample_isr); timer1_...

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