hi
I am making a request responce architecture using 8051 MCUs. I have connected two MCU with port1. One MCU is P87c51RD+ and other is AT89C51. I am using external interrupt for this purpose.
The request part is working but responce part is not working.
Request:
I send a value 0xF0 on port1 from P87c51RD+ and generate the interrupt1 of AT89C51 from it. The interrupt is generated and in that routine i change the value at port1 and change it to 0x80.
Rsponce:
and then from this interrupt routine i call the external interrupt of p87c51RD+. In the ISR of this routine i again change the value of port1 to 0x40.

but this is not working when i test the code the value on port1 is 0x80 and responce is not generated.
I am using keil and proteus as simulator.
regards
Farhan Arshad.