Datasheet

180
AT8xC51SND1C
4109E–8051–06/03
Registers Table 151. KBCON Register
KBCON (S:A3h) – Keyboard Control Register
Reset Value = 0000 1111b
Table 152. KBSTA Register
KBSTA (S:A4h) – Keyboard Control and Status Register
Reset Value = 0000 0000b
76543210
KINL3 KINL2 KINL1 KINL0 KINM3 KINM2 KINM1 KINM0
Bit
Number
Bit
Mnemonic Description
7 - 4 KINL3:0
Keyboard Input Level Bit
Set to enable a high level detection on the respective KIN3:0 input.
Clear to enable a low level detection on the respective KIN3:0 input.
3 - 0 KINM3:0
Keyboard Input Mask Bit
Set to prevent the respective KINF3:0 flag from generating a keyboard interrupt.
Clear to allow the respective KINF3:0 flag to generate a keyboard interrupt.
76543210
KPDE - - - KINF3 KINF2 KINF1 KINF0
Bit
Number
Bit
Mnemonic Description
7KPDE
Keyboard Power Down Enable Bit
Set to enable exit of power down mode by the keyboard interrupt.
Clear to disable exit of power down mode by the keyboard interrupt.
6 - 4 -
Reserved
The value read from these bits is always 0. Do not set these bits.
3 - 0 KINF3:0
Keyboard Input Interrupt Flag
Set by hardware when the respective KIN3:0 input detects a programmed level.
Cleared when reading KBSTA.