N82C55A Description
PORT C PINS 4 7 Upper nibble of an 8-bit data output latch buffer and an 8-bit data input buffer (no latch for input) This port can be divided into two 4-bit ports under the mode control Each 4-bit port contains a 4-bit latch and it can be used for the control signal outputs and status signal inputs in conjunction with ports A and B PORT C PINS.