I have a Portenta H7 Lite MCU which is installed on a Portenta H7 Breakout Board. I connected a 14-segment Qwiic alphanumeric display from Sparkfun to the I2C1 port on the breakout board. When I power up the board with this combination, the Battery Charger LED on the H7 lights up orange but the MCU program otherwise runs normally. If I disconnect the Qwiic display, the orange LED is OFF and the code runs normally. I am not doing any battery charging.
Why is this happening, and what is the meaning of the battery charger LED being ON?
Yes, I am unplugging it. It's not a screen, but a 14-segment LED alphanumeric display (4 digits). I'm powering it with the 3V3 and GND pins that are part of the I2C1 port. The display does not come on or light up when I plug it in, but for some reason causes the orange LED, the battery charger LED, on the H7 main board to light up when the display is connected to the port.
My guess:
The orange charge LED is controlled by the PMIC chip on board. It is not related to any current, pin etc., just an I2C write happened to the PMIC chip.
it does not measure any voltage, it can be controlled just via an I2C write command (to the PMIC chip register).
I guess: you connect your I2C board at the same I2C bus used internally also to program the PMIC chip. If both devices have the same I2C slave address - it can happen you want to write to your device but you also write to the PMIC chip on board (in parallel).
So:
check, if you connect your I2C device to the same I2C bus used internally - use a different I2C device (one of the 3 possible - be aware of: the other two do NOT have pull-ups, the internal I2C with PMIC on it has pull-up)
check the I2C address used for your device: avoid a conflict with an already existing I2C slave address (PMIC should be 0x08). Don't connect two slaves with same address on same bus: a write would write into both chips.
I guess, you write by mistake also to the PMIC chip (the register which controls the orange LED).