deactivate pulse that is sent when the module is started

All ESP8266 boards running MicroPython.
Official boards are the Adafruit Huzzah and Feather boards.
Target audience: MicroPython users with an ESP8266 board.
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anjamago
Posts: 1
Joined: Fri Jan 12, 2018 3:44 pm

deactivate pulse that is sent when the module is started

Post by anjamago » Tue Feb 06, 2018 2:55 pm

I have a program made for my esp8266 works very well but I have a problem, the esp sends me a signal at the moment of starting, this signal activates an inteructor and is a fault that I want to solve to avoid that when there is no current and it returns no activate the intervisor without being ordered, as I can disable is pulse there is some way to set parameters for the pins so that it does not send signal through the ports when starting the computer
:roll:

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deshipu
Posts: 1388
Joined: Thu May 28, 2015 5:54 pm

Re: deactivate pulse that is sent when the module is started

Post by deshipu » Tue Feb 06, 2018 4:28 pm

I can't quite make sense of what you wrote. Do you think you could describe it again, slowly, and with more detail?

cefn
Posts: 230
Joined: Tue Aug 09, 2016 10:58 am

Re: deactivate pulse that is sent when the module is started

Post by cefn » Tue Feb 06, 2018 5:09 pm

I think the OP is describing that on power cycle, the particular pin he is using goes high on boot, before the CPU configures it in the intended way through software (no longer high). The concern seems to be that even if they find a workaround, (e.g. power it up, then later plug it in) that an unexpected power cycle such as a power cut will simply trigger the same high pulse on boot and put them back to square one.

However, as @deshipu points out, there is almost no detail here.

Which board are you using? Which pin are you using? Why does sending a high pulse on boot matter to your application?

In particular, some boards have pull-up/pull-down resistors pre-wired to certain pins to control their logic level at boot, and hence the startup configuration of the ESP8266. These can later be configured as outputs to drive a high or a low logic level (overcoming the pull-up/pull-down), which could potentially eliminate this issue. Looking at the schematic for your particular board and switching which pin you are using for output to one which has a built-in pull-down could make a world of difference. Adding your own pull-down resistor to an appropriate pin (so it doesn't appear to send a pulse on boot) would also potentially fix it.

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