Grove connector as Serial

[metanav]

I wanted to connect a serial device to the Nano ESP32 using the Grove connector. I was able to do this by reassigning the A4 and A5 pins as RX and TX. However, this caused the battery charge reading functionality to stop working, as it relies on I2C communication. Can the STM32 read the battery status when it is powered on?

[gbr1]

Hi @metanav !
"Officially" I can say which Alvik doesn't support UART Grove but only I2C ones. This is why we use I2C communication in the idle() method.

But if you want to hack you can!

First at all you need to disable the battery check when the robot is off or just restarting the serial when the robot is on.
You can check if the robot is on using the is_on() method. Just to give you the right context, this is the line which restart I2C on A4 and A5 when the robot is turned off.
Note: your code must be executed after alvik.begin()

Now that your program is able to use the uart properly, you need to adapt the carrier firmware.
The firmware has this object ext_wire.
This is used for two reasons:

1. the carrier appears as a device with 0x2B address when you scan I2C from the Nano ESP32.
2. users can make this I2C a controller and electrically isolate Grove/Qwiic I2C from the nano writing custom firmware which uses connectExternalI2C and disconnectExternalI2C, check here please.

So, you need to comment following lines:

1. ext_wire initialization
2. ext_wire begin

After these operations everything should work smoothly.