@pac_71 No. A Pull-Up resistor connected between P8 and 3.3 V dose not require extra action. At a value of 4.7k or 10k, some other units, the ESP32 or a logic output of an external device, can drive it low when needed. No switch is required. P8 is also used for the SD card. So connecting it directly to 3.3V would block the SD card.
# boot.py -- run on boot-up
from machine import UART
uart = UART(0, 115200)
#disable the wifi radio
from network import WLAN
#disable the bluetotth radio
from network import Bluetooth
@protonx I made myself a base board too for the Pycom modules. A Kicad sketch is here: https://github.com/robert-hh/Pycom-baseboard
It uses pre-built modules for USB/Serial and SD card. I did not want to deal with SMD parts, and space did not matter. It also has the espressif logic for activating the bootloader, and jumpers for the connection to Reset, Tx, Rx and P2.
Not that this costs less than an Pycom expansion board, but it makes fewer troubles when using (no PIC, standard drivers, ..)
@robert-hh OK, I set up some code to try this out, several timers at different periods and several threads including one to start LTE, send an SMS and then deinit. From what I can see, the timers do NOT get interupted by the LTE device. It seems the timer counts are retained and dumped to REPL as soon as possible (buffered apparently). There is some corruption/mixup of REPL lines but all the timer flags are there
I will investigate a bit further and see if I can use this to my advantage. One thread/timer I will need will be at 11uS preferably, so as it is too fast to capture by eye, I'll have to write to a file to a file to evaluate any impact by the LTE device. Biggest constraint might be the actual time to write to disk. A FIFO data buffer is probably a good solution - some work to do there.
The test code was pretty rough and ready so its needs a lot of refinement to be truly useful as a valid test.
When I used I2C bus 1 (instead of default 0) and pins P10 + P11, I got the I2C bus to work. I've have the impression that I2C bus 0 and pins P9 + P10 might be reserved or something like this. Can anyone confirm if they're used by UART or button on Expansion board or something like this?
Does anyone know, if 10x orange led blink on Expansion board is some error message? I did not find anything related to this while searching.