Required pin connections for programming LoPy/SiPy/WiPy
I'm developing my own custom expansion board for the PyCom development modules (not OEM modules). I'd like to know the required pin connections to allow my board to program reliably.
So far, connecting GND, TX and RX works most of the time but I'm having issues when the board is in deep sleep. Do we also need to connect CTS and RTS to somehow reset the board for programming when it's in deep sleep?
@robert-hh Thanks for the detailed reply and clarifying that it's DTR and RTS!
@megabyte You need RX, TX and GND, and for programming you have to connect P2 (=GPIO0) to GND and pul Reset to GND. If you make your own Baseboard, you can use the circuitry used by must other boards to perform this GPIO0/Reset toggling, which is supported by esptool.py. See here for an example: https://cdn-learn.adafruit.com/assets/assets/000/041/630/original/feather_schem.png?1494449413
The ciruitry I'm talking about is Q1 and Q2 and the connected resistors. It expects DTR and RTS for switching.