In what format is the bq27531-G1 Instantaneous Current register signed? It looks like two's complement - please confirm I've got a proper method of decoding.
I first read two bytes then concatenate them into a 16-bit word. This procedure is working for Voltage and other unsigned values.
With a reference discharge load of about -50mA, I am reading back Instantaneous Current=65487.
Two's complement conversion (add one then change the sign) gives me -64588 (-1111 1111 1101 0000). Flipping the bits (-0000 0000 0010 1111) gives -47mA.
A colleague suggested a shortcut - I tried subtracting 65535 from the 16-bit word (65487) and I actually get a decent answer of -48mA. But I am hesitant to use this shortcut without understanding what's going on. There's one correct way to do this...
Please advise on the signing format.
Thanks for the support,
Bryan