How many IO pins in C8051F975


I can't tell how many IO pins that are available on the C8051F975.
SiLabs website, Farnell and the datasheet p. 42 says 19 IO pins, so I guess that is correct, but the according to the datasheet p. 38 there is 21 IO pins.

C8051F975 datasheet

I'm trying to use this MCU in a schematic, but I cannot get it finished before I know which of the pins are actually available.

Best Answer

There are 24 pins (+ GND pad) on the QFN-24 package on page 38.

2 pins are VDD and GND -> 22pins.
1 pin is RST/C2CK -> 21.

If you want to use a hardware debugger, then do not use
1 pin P5.2/C2D as an I/O -> 20 I/O pins.