To wake after a deepsleep and before it expire, I would like use a reset pulse generator like CAT871. This is necessary because I want wake up the ESP8266 when a free fall interupt is generated by an accelerometer and this interrupt is a latched signal and not a pulse.
Please coud you tel me what has to be the minimum negative pulse lenght?
I can select between 2.2 ms and 70ms.
Thenks and regards.
Minimum RESET pulse
Re: Minimum RESET pulse
Postby chaeplin » Mon Dec 14, 2015 12:47 am
I think a pulse is needed.
When reset pin is in low, esp is in reset state and clock is not running.
I have a dash like button using reset and deepsleep.
With following circuit, if switch is on, esp is in reset state and not running code. After releasing switch, esp start.
https://raw.githubusercontent.com/chaep ... /npntr.png
more:
external one shot reset using monostable flip flop ( http://www.bowdenshobbycircuits.info/page9.htm )
- pin 16 go LOW while running(digitalwrite to low) to prevent more reset.
https://raw.githubusercontent.com/chaep ... _schem.png
ref: viewtopic.php?f=7&t=259&p=1023&hilit=reset+pulse#p1023
When reset pin is in low, esp is in reset state and clock is not running.
I have a dash like button using reset and deepsleep.
With following circuit, if switch is on, esp is in reset state and not running code. After releasing switch, esp start.
https://raw.githubusercontent.com/chaep ... /npntr.png
more:
external one shot reset using monostable flip flop ( http://www.bowdenshobbycircuits.info/page9.htm )
- pin 16 go LOW while running(digitalwrite to low) to prevent more reset.
https://raw.githubusercontent.com/chaep ... _schem.png
ref: viewtopic.php?f=7&t=259&p=1023&hilit=reset+pulse#p1023
Re: Minimum RESET pulse
Postby piebat » Mon Dec 14, 2015 5:21 pm
Thanks for help. I need that the reset pulse is generated even if the line is kept low, because I need to verify from where came the reset, when the system wakeup. So I found the answer: "how long at least shoud be low the reset to achieve it?" at http://bbs.espressif.com/viewtopic.php?p=5027#p5027, it is 100us, and I think that the CAT871 IC could work fine if I use two line as manual reset.
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