use of 8255 programmable peripheral interface

[erece]

In 8085 nicroprocessor , we have 256 ports, which means we can connect 256 I/O devices with 8085 at a time (i'm not sure).
Then why do we use 8255 programmable peripheral interface to interface I/O devices with 8085 as it only has 3 ports??

 

[kasutaja]

Seem You are confusing software ports with hardware ones. If connected to CPU bus 8255 will provide _real_ I/O device which can accessed via CPU software ports.