I/O extender

[mackrackit]

Thx Mackrackit.
It only High and Low I/O. i think shift register would be a good idea. 4 to 8 lines. Bringing total of 128 bit of I/O. Meaning total pin require is 7 ( 4 for address, Clock, Load and Serial Data ). Am i right ?

Thx Luciano for the suggestion. It really a new thing for me. But why both MCP23008 and MCP23016 have 3 addresses ? Can MCP23016 work with 16f84a ?

If you go with shift registers you will need a clock/load set for inputs and one for outputs.
Look at a HC595 for output and HC165 for inputs (I think, been awhile)

The solution that Luciano gave looks nice. I did not know about these chips. Learned something new and it is the fisrt day of the year Off to a good start.

[mister_e]

Those microchip I/O extender are really nice. In the past i also used PCF8574A, maybe easier to find it locally 'cause it's a very old one.. still popular i guess.