Slow GPIO interrupts question (again)
Posted: Sat Aug 04, 2018 12:53 pmHi.
I'm trying to get an ESP8266 (Wemos D1R2) to react to a falling edge signal from a comparator within about 0.5uS of receiving it via an external interrupt on a GPIO pin (see the attached image, the blue channel is the signal that goes to the interrupt pin).
However, there is significant delay (the yellow signal - output of a GPIO pin of the ESP8266), typically about 10-15us, between the firing of the external interrupt and the execution of the interrupt handler, which is too much for this application.
I've read through the forum, and while there are some posts on the subject, e.g.
[1] viewtopic.php?f=13&t=2511&p=14603&hilit=slow+interrupts#p14603
[2] viewtopic.php?f=28&t=8745&hilit=slow+interrupts
and the most illuminating one, here [3] viewtopic.php?p=52679#p52679, I have not seen an example that is easy to follow for a newbie.
Also, since all comments are from some time ago, I was wondering if a better solution has become available in the meantime, and in which programming environment (I've so far tried the Arduino and esp open-rtos/open-sdk).
If anyone can point me to an example of doing fast processing of external interrupts while I'm digging through the available references and code, it would be very helpful and much appreciated.
Thanks in advance,
I'm trying to get an ESP8266 (Wemos D1R2) to react to a falling edge signal from a comparator within about 0.5uS of receiving it via an external interrupt on a GPIO pin (see the attached image, the blue channel is the signal that goes to the interrupt pin).
However, there is significant delay (the yellow signal - output of a GPIO pin of the ESP8266), typically about 10-15us, between the firing of the external interrupt and the execution of the interrupt handler, which is too much for this application.
I've read through the forum, and while there are some posts on the subject, e.g.
[1] viewtopic.php?f=13&t=2511&p=14603&hilit=slow+interrupts#p14603
[2] viewtopic.php?f=28&t=8745&hilit=slow+interrupts
and the most illuminating one, here [3] viewtopic.php?p=52679#p52679, I have not seen an example that is easy to follow for a newbie.
Also, since all comments are from some time ago, I was wondering if a better solution has become available in the meantime, and in which programming environment (I've so far tried the Arduino and esp open-rtos/open-sdk).
If anyone can point me to an example of doing fast processing of external interrupts while I'm digging through the available references and code, it would be very helpful and much appreciated.
Thanks in advance,