PIA 6820/6821 chips

[mike11]

Are the 6820 and 6821 interchangeable ??? I'm working on a pin here that has 6820s and one is bad..... The reference I have for repairing it references that chip as a 6821..... When a make sure it'll work ...... It's a bally -35 mpu

Thanks

 

[KenLayton]

6820 and 6821 are directly interchangeable.

 

[mike11]

Thanks ken that's great to know ...

 

[mike11]

Are 8255s usable as well or only with z80s ??

 

[viperrwk]

If you mean can you sub between a 6821 and 8255? No not at all. The 8255 is an Intel design and was used with the 8085 and 8086 Intel processors in addition to Z80s.The 6821 is a Motorola design by comparison.

viperrwk