Sir, i want to connect 13 relays to microcontroller nd i hav only 4 pins to connect these relays.... so i am using decoder ic to connect the outputs.... so please tell me how to program for this...
there are '51 devices with 64 pins, why Mickey Mouse it?
But SPI-driven shift registers are quite practical. Especially since some of them have very powerful, sometimes current-controlled, outputs or open-collector outputs able to directly handle 12V relays (at least if the relays have freewheel diodes).
Cause it's a Steamboat Willie type development effort?