Replacing shift register with PIC

[TonyA]

Hi,

I was wondering if it is possible to replace a 4021B (parallel to serial) shift register chip with a PIC using shiftin and shiftout functions?

I am assuming that I would first need to shiftin the latch and clock data from the master, then shiftout the (serial data) bits to the master.

The "master" in this case is a Nintendo NES video game system which uses a standard 4021B shift register in it's joystick to read 8 buttons in a parallel fashion, and then shifts the 8 bits out serially to the data input pin of the NES joystick input port.

The NES sets the latch line low when it is ready to receive the serial data from the shift register. The shift register also receives clock data from the NES (master), but I'm not sure what to do with the clock data received.

I want to mimic a 4021B shift register with my pic, but not sure how to handle the data received from the "master" clock and latch.

Hope I'm not too confusing. If I am I'll try to clarify.

Thanks for any help,
T