ESP8266 Community Forum

[RichardS]

- Sun Feb 12, 2017 2:18 pm #62465 Finding the perfect value that lies on some hairy fairy borderline of working and not working is not good.... resistors change value due to many circumstances, so your borderline solution tomorrow, or next week becomes your WTF moment.... because it "WAS" working.... remember... "WAS working" should be replaced with "it was on the edge of working"

A resistor really only works when you have only a switch to ground connected on reset pin, and not the amount of other circuitry as you do that interferes with it....

In conclusion:



Thanks for listening
RichardS

PS. And how do I know.... just say.... "been there, done that"

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- Sun Feb 12, 2017 4:58 pm #62475 Ha, I gave up barking up that tree.
I gave examples and calculations why it won't work reliable but still people - only for this topic - look at the datasheet. Obviously a (chinese!!!) datasheet can bend natures law and has more credibility than experience and math.

- Mon Feb 13, 2017 6:34 am #62489

resistor???? diode maybe
RichardS

Thanks for the reply! I found the below quoted text (or similar ones) in another thread but for a similar (to my understanding) problem. For this reason tried the resistors. To be honest, I didn't try the schottky diode proposal, I will try that also.

This is because you used a plain wire between RST and GPIO16.
The issue is that GPIO16 provides a strong HIGH during deepSleep and your external reset from Serial-TTL is fighting to make a reset, but loosing, the GPIO16 is the strongest.

To avoid such issue, simply replace the wire by a 470R or 1K between GPIO16 and RES, which will allow the Serial-TTL to win. (you can also use a schottky diode with the cathode on GPIO16 side)

- Mon Feb 13, 2017 2:52 pm #62515

Finding the perfect value that lies on some hairy fairy borderline of working and not working is not good.... resistors change value due to many circumstances, so your borderline solution tomorrow, or next week becomes your WTF moment.... because it "WAS" working.... remember... "WAS working" should be replaced with "it was on the edge of working"

A resistor really only works when you have only a switch to ground connected on reset pin, and not the amount of other circuitry as you do that interferes with it....

In conclusion:



Thanks for listening
RichardS

PS. And how do I know.... just say.... "been there, done that"

The diode solution works perfectly. Thanks a lot.