ATMEGA32L & PPI (8255) interface question

[NTFS]

ppi 8255

Hi

In a project I should to handle many I/Os (GLCD, K/B, many lamps, buzzer, 2 fans, 4 sensors, heater and a DC motor ). So I used two PPI (8255) and micro ports.

Now how can I handle PPI control signals? (A0, A1, RD, WR, CS)

I thing, I should do that manually by micro ports, because I couldn't find a method that when I write to PPI, micro does [WR, A0, A1, CS] signals automatically.

So two questions:

1) what is the best method to interface these many I/Os to micro? Is my method good?

2) How to handle control signals? if I active these signals at a same time, does PPI
work? or I have to do them in separate times? for example first I should active
CS, A0, A1 then put data on port (data bus) and then active WR (write) signal



Thanks in advance.

 

[IanP]

i2c 8255

This ATmega microcontroller had not been designed to co-operate with older PIOs such as the 8255, so maybe you can consider the already built-in two-wire interface, namely the I2C, and expand the number of IOs by adding some PCF8574-s or any other I2C-compatible expanders ..
https://www.i2cchip.com/pcf8574.html
Using 8255s is still an open option, but it can be a little bit tricky, especially if you are not familiar with the multiplexed A/D parallel bus ..

Rgds,
IanP

 

[nandhu015]

interfacing ppi to atmega32

Another Simple way is to use a serial in parallel out shift registers

There are a lot of examples of lcd using these chips, google and find one

Nandhu