Clarify as in understand how it works? The row select chip sources current and the column data chip sinks current. The pic is connect to both chips via a 8 bit wide data bus. I'm not familure with those chips and I havn't read the webpage either. I'll be guessing that you put your row byte on portb and pulse porta.1 to shift it into the row chip. Then you set portb for column data and the you pulse porta.0 to shift portb into that column chip.
E.g.
Put %00000001 on portb
Pulse porta.1
Put %00000001 on portb
Pulse porta.0
You will now have the bottom left led on.




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