Interrupt driven rs232 port on different pins

[dex2k]

Is it possible to get interrupt capabilities on other pins than the hardware pins rx/tx on a pic18f4550 or pic18f452?

I need to do some SPI operations and have an interrupt enabled for a serial port at the same time.
Is this possible, or how do you people cope with sharing the dataout pin?

[PCM programmer]

The INT0, INT1, or INT2 pins can be used as the Rx pin for a soft UART.
You can then use the corresponding external interrupt (INT_EXT,
INT_EXT1, or INT_EXT2) to detect the leading edge of the start bit.
(This is the falling edge). The incoming byte is then read with a getc()
or fgetc() statement, inside the INT_EXTx interrupt service routine.

However, there are many PICs to choose from. The best way is to
use a PIC that has the SPI and UART modules on separate pins.

[dex2k]

its about 03:00 at night here, just woke up with the same idea as yours, what an odd world we live in

i have seen that some of the "great" pic series has separate uart and spi pins, but i dont have that option, so the external interrupt idea must be my road to victory

thanks for your quick help

[Ttelmah]

This however is very dependant on using a relatively slow serial rate. Look at the RS485.c driver/example, which (depending on configuration), uses an interrupt triggered 'soft' serial stream for the RS485 comms, and hardware serial for it's general I/O. The problem with the 'soft' approach, is that if the interrupt occurs on the edge of the incoming character, there is a significant time interval, before the code gets into the handler. If this is too long (relative to the 'bit' width of the incoming stream), data may get lost/corrupted. For a chip at 40MHz, this delay, is perhaps 4uSec, and reasonable serial rates can be handled, but if you are running at a much lower clock rate, this needs to be considered...
You could also consider a separate SPI UART module.
On chips like the 18F2550, it is possible to have the UART in use, and also the SPI, in receive mode only.
Remember also that bit-banging SPI, is fairly easy, and fast.

Best Wishes