UPD8279C

The PD8279 is a programmable keyboard and display inputloutput device providing the user with the ability to display data on alphanumeric segment displays or simple indicators. The display RAM can be programmed to function as a 16 x 8-bit or dual 16 x 4-bit memory and can be loaded or read by the host processor. The display can be loaded with right or left entry with an auto-increment of the display RAM address. The keyboard interface provides a scanned signal to a 64 contact key matrix expandable to 128. General sensors or strobed keys may also be used. Keystrokes are stored in an 8 character FIFO and can be either 2 key lockout or key rollover. Keyboard entries generate an interrupt to the processor.

The features of PD8279 can be summarized as (1)programmable by processor; (2)32 hex or 16 alphanumeric displays; (3)64 expandable to 128 keyboard; (4)simultaneous keyboard and display; (5)8 character keyboard-FIFO; (6)2 key lockout or key rollover; (7)contact debounce; (8)programmable scan timer; (9)interrupt on key entry; (10)single +5V±10% power supply; (11)fully compatible with 8080A, 8085A, PD780 (Z80).

The absolute maximum ratings of PD8279 are (1)power supply voltage, VDD: -0,5 to +7.0V(With respect to VSS); (2)power dissipation, PD: 1.0W; (3)operating temperature, TOPT: 0°C to +70°C; (4)storage temperature, TSTG: -65°C to +150°C (Comment: Exposing the device to stresses above those listed in the absolute maximum ratings could cause permanent damage. The device is not meant to be operated under conditions outside the limits described in the operational sections of this specification. Exposure to absolute maximum ratings for extended periods may affect device reliability).