Rainbow Electronics AT89C51SND1C - Manual (Page 180)

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
7 6 5 4 3 2 1 0
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.
7 6 5 4 3 2 1 0
KPDE - - - KINF3 KINF2 KINF1 KINF0
Bit
Number
Bit
Mnemonic Description
7 KPDE
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.