Q
Can I use pin P2.3 in ADuC845 as a general purpose pin while using SPI in
master mode?
A
Yes you can. The SS pin is only used when the part is used as an SPI slave
device.
If the part is used as a Master device then the SS functionality is not
required and P2.3 can be used according to the alternate options given in the
Datasheet...T2 input or standard digital port pin.