81C51SL - KEYBOARD CONTROLLER

Table 1 Pin Descriptions Symbol Type Description VSS Circuit ground potential VCC Supply voltage during normal Idle and Power-Down operation nominally a5V g10% for 8XC51SL a3 3V g 0 3V for Low Voltage 8XC51SL PCDB0 7 I O Host interface data bus An 8-bit bidirectional port for data

• I O PU P22 A10 I O PU P23 A11 I O PU P24 A12 I O PU P25 A13 I O PU P26 A14 I O PU P27 LED4 I O OD VSS GATEA20 O PCDB7 IO PCDB6 IO PCDB5 IO PCDB4 IO PCDB3 IO PCDB.