Co-simulation of ARM and sensor

I'm trying to figure out how I can simulate a sensor and it's 
interaction with a microcontroller.

1) I have successfully compiled and run simple programs on 
CodeSourcery's ARM7 simulator.  I'd either like to have an external 
process talk to this simulator or run the program on an actual device 
and talk to the external process from that device (through JTAG 
presumably).

A few options I've tried:
1)  Once gdb is running my ARM7 SW, could I somehow connect to gdb to 
read/set registers?
2)  Could I open a pipe to another program that I could use for 
simulation of the sensor.  I've tried this a little bit but haven't 
figured out how I can open the pipe.


Any other suggestions.  I'm not sure if I'm even on the right track 
here.

Thanks!

Mike