I would not recommend an interrupt controller chip. These ancient beasts were designed for older 8 bit micro processors and are not very suitable for use in an 8051 type of environment. A more suitable approach would be to use one of these possibilities:

A) Use a small CPLD to implement the 8-way interrupt edge capture. This can then in turn be signalled to the 8051 via an single external interrupt. The ISR can interrogate the CPLD to see which of the interrupts have occurred.

B) Equip your board with multiple low cost controllers such as LPCxxx Philips parts that handle two interrupts each. THen have these parts communicate back to the main controller.

C) Look for a microcontroller that has a "Keyboard interrupt module". These often are implemented in such a way that a single interrupt is generated when any one or more of a number of "keypad" inputs are activated. The iSR then accesses a port to see which inputs are active.

Your choice of which approach to use would be made based upon how complex the interrupt support logic for each of the inputs is.

Michael Karas