Hello @ankurj77

Short answers:

• no, most likely analog signals cannot be read from M5Core2 port A due to the two pull-up resistors.
• no, port A doesn't need to be enabled first. It is already enabled.
• no, analog signals don't need a clock. The clock is used for I2C.

Note: as mentioned before, I don't own an LM35 and cannot test this myself, so my conclusions, solely drawn from reading the schematic, could be incorrect.

Long answer:
M5Stack has defined three Groove ports A, B and C.

• A (red) is by default used for I2C (found on M5Core2)
• B (black) is by default used for DAC / ADC (found on M5GO Bottom2)
• C (blue) is by default used for UART (found on M5GO Bottom2)

There are exceptions to the above where a function can be setup and used on a port not meant for that. In case of port A in M5Core2 there are this two pull-up resistors already in place (which are required for I2C to function) but they also might or might not influence other usage.

Given that in your case you are reading the same value independent of the actual temperature, I assume that yes, the pull-up resistor messes with the analog signal from the LM35 and therefore port A most likely cannot be used for the LM35.

Your best bet would probably be to get an M5GO Bottom2 and then use port B (ADC) for the LM35. Or you could get an EnvIII Sensor (temperature and humidity air pressure) which uses I2C and works on port A.

Thanks
Felix

Hello @Minxster

I haven't looked into either of the two libraries in depth so it's difficult to say which will be more helpful for your particular M5Core2 project. @Rop was very active for a while but then moved on to non M5Stack related things I guess.

That said, in the past M5Stack engineers weren't too busy adding new features (or fixing bugs) in their libraries once a particular piece of software has been out. So I don't expect too much activity in the M5GFX library except maybe small adaptions to support new M5Stack devices which have a screen.

Thanks
Felix

Hello @benalb

according to the C Back Driver schematic the four channels are powered from the +BAT pin the M5StickC provides but is missing when using an M5Atom with the atom-mate.

Thanks
Felix

Hello @Radu

this is not an actual IC but the describes the M5Stack bus connector which is used for the interconnection between M5Stack cores and modules.

Thanks
Felix

Hello @ankurj77

according to the M5Core2 schematic, GPIO32 and GPIO33, both already have a 5.1 k pull-up resistor in place, since Groove port A normally is meant to be used for I2C.

That said, I don't have an LM35 to test myself, but most likely this pull-up resistor has an influence on the final value read from the analog output of the LM35.

Thanks
Felix

Hello @benalb

the .cpp file should go into the src instead of the include directory, else it doesn't get compiled nor linked.

Thanks
Felix

Hello @Devilstower

sorry, at this time I am out of ideas.

Thanks
Felix

Hello @ajb2k3

What worked for me on macOS Big Sur 11.5.2 is using the ESP32C3 built-in USB via GPIO18 and GPIO19.

What also worked for me on macOS Big Sur 11.5.2 was downloading and installing this driver CH9102_VCP_SER_MacOS from here. After a reboot and plugging in M5StampC3 via USB this port show up /dev/cu.wchusbserial... (in addition to /dev/cu.usbmodem... which did not work).

Thanks
Felix

Hello @HaSch

well, disabling downloading the stub doesn't help anyway - so my idea is moot. I've just setup a machine with macOS Big Sur 11.5.2 and with or w/o downloading the stub the download process ends in an timeout error.

What worked for me on macOS Big Sur 11.5.2 however is using the ESP32C3 built-in USB via GPIO18 and GPIO19.

Thanks
Felix

Hello @HaSch

sorry, I don't know if you're missing a driver or not. On Ubuntu 20.04 there was no need to install a driver. Whatever is required seems to already be included in the stock version of Ubuntu 20.04.

I was wondering, in your case it fails while 'Uploading stub' which as I understand is not necessarily needed. In menuconfig there is an option Serial flasher config - Disable download stub which by default is unchecked. Maybe try to disable the downloading of the stub and see if that gets you any further.

BTW: what operation system and version are you using? Window? MacOS?

Thanks
Felix