[SOLVED] Sketches will upload but don't run

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Re: Sketches will upload but don't run

By burkmurray
- Sun Aug 02, 2015 3:09 pm #24842 Do you have your serial adaptor connected to +3v on your board? That seems like a bad idea. You need a common ground, but the adaptor should be powered by your PC's USB port, and the ESP by an external supply.

That could explain why your circuit worked on one PC but not another: different current from the USB ports.
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Re: Sketches will upload but don't run

By PaulRB
- Mon Aug 03, 2015 5:47 am #24879 Thanks Neil and burkmurray, I will try out the theory this evening. Feeling hopeful. Yes, I do have the 3.3V outputs from the serial adapter and the esp's power supply connected together. If disconnecting the 3.3V from the adapter fixes the issue, I will be interested to know your theories about why this causes a problem, for my personal education.

Checking out your circuit, Neil, I have a couple of questions:

R4 & R5: Are these needed to reduce the signal on a 5V only serial adapter? Are they strictly needed with an adapter set to 3.3V output, other than for safety reasons?

C1 & R7: These debounce the reset switch? Why is that important?
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Re: Sketches will upload but don't run

By kolban
- Mon Aug 03, 2015 7:53 am #24887 Howdy Paul,
The R4 and R5 are as you described. IF and ONLY IF ... the TX of the UART to USB were 5V, they would reduce the voltage to 3.3V on input to the RX of the ESP8266. I do not believe that the input to the ESP are 5V tolerant and wanted to protect the device. If the output of the UART is 3.3V then R4 and R5 should not be needed at all. However, I do not believe they do any harm to signal quality IF the output is still 3.3V. So it becomes a question of "safety" and, in my mind ... "why not".

C1 and R7 are not debounce ... I added them for "momentary push". I believed (and still do until I learn otherwise) that bringing the RESET pin of the ESP low causes it to reset and the device doesn't start operating again until RESET goes high again (this may be bogus ... but it was and is my current thinking). C1 and R7 allow me to press the button and the device immediately resets. There is no need for me to release the button before it starts to reset.
Neil
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