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CircuitSetup / Expandable-6-Channel-ESP32-Energy-Meter

Hardware & Software documentation for the CircuitSetup Expandable 6 Channel ESP32 Energy Meter. Works with ESPHome and Home Assistant.
https://circuitsetup.us/product/expandable-6-channel-esp32-energy-meter/
MIT License
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Rev 1.4 add-on board and GPIO35 #4

Closed presslab-us closed 4 years ago

presslab-us commented 4 years ago

The rev 1.4 add-on board has changed to GPIO35 for one of the chip select signals. This GPIO cannot be used because it is an input only pin on the ESP32.

It's not a problem for me, I just moved to another chip select. But I thought I should mention it.

CircuitSetup commented 4 years ago

Thank you, I actually just realized this myself. Itll be corrected in the next revision, probably back to GPIO 2, since there are no other available pins that aren't already used.

presslab-us commented 4 years ago

It looks like on my ESP32 board, GPIO 2 is used for the blue LED. In EmonESP this blinks when WiFi is connected. I have disabled that blinking in code and soldered a jumper from GPIO 35 to GPIO 2. It seems to work fine; I can even see the LED dim slightly as the CS is toggled. I haven't looked with a scope, but I'd assume the load of the LED has little effect on the signal integrity.

presslab-us commented 4 years ago

With GPIO 2 being used for CS, I now see the problem where I cannot reprogram the ESP32 through the USB port while it is plugged into the add-on board. The source of the problem seems to be that the CS pin is pulled high with a 10k resistor on the add-on board, and this messes up the ESP32 bootloader.

CircuitSetup commented 4 years ago

Is GPIO 35 or 2 causing the boot issue when pulled high?

presslab-us commented 4 years ago

GPIO 2 causes the boot issue. I have disconnected GPIO 35. The documentation below states that "GPIO2 must also be either left unconnected/floating, or driven Low, in order to enter the serial bootloader." https://github.com/espressif/esptool/wiki/ESP32-Boot-Mode-Selection

CircuitSetup commented 4 years ago

GPIO 35 was changed to GPIO 2 in the next revision of the add-on board. I'll make a note to disconnect the jumper for 2 if programming the esp32.

presslab-us commented 4 years ago

That sounds good. It also might make sense to swap GPIO 35 for GPIO 15. And then make the last add-on board GPIO 2. This way only someone with all 6 add-on boards will need to disconnect the jumper for programming.

CircuitSetup commented 4 years ago

That would have made more sense. For now its on GPIO 2 in the 3rd position on the jumper. Maybe I'll make that change in the next revision. Closing this for now.