Pololu 18v25 CS (V+ logic side)

Support Motor controllers/drivers and motors
1

Hi all,

I was wondering if anyone know’s my hiccup here:

I currently have a 18v25 CS board with a 14V power supply connected to the large V+ pad. The brushed DC motor is connected to OUTA/OUTB.

On the logic side, I have the small V+ pad connected to my uC’s ADC pin. Its set for 12-bit (4095) readings.

When powered on, I’m seeing 4095 coming out of the V+ logic side pin. To my understanding, its always going to read out 4095 since there’s no reference voltage.

Can this pin act as a voltage sensor?
Or am I looking at this pin in the wrong way? Thank you.

2

Hello.

That pin is just internally connected to the large V+ pad, so you are ultimately directly connecting your 14V power supply to your ADC input. I don’t know what MCU you are using, but something like this will destroy the typical microcontroller. If you want to monitor your supply voltage level with your ADC, you should do so through voltage divider that reduces the V+ output to a level that is acceptable for your microcontroller.

- Ben