Datasheet
89
4337K–USB–04/08
AT89C5130A/31A-M
17.2.2 Power Reduction Mode
P1 inputs allow exit from idle and power down modes as detailed in section “Power-down Mode”.
17.3 Registers
Table 17-1. KBF Register
KBF - Keyboard Flag Register (9Eh)
Reset Value = 0000 0000b
7 6 5 4 3 2 1 0
KBF7 KBF6 KBF5 KBF4 KBF3 KBF2 KBF1 KBF0
Bit Number
Bit
Mnemonic Description
7 KBF7
Keyboard line 7 flag
Set by hardware when the Port line 7 detects a programmed level. It generates a
Keyboard interrupt request if the KBKBIE.7 bit in KBIE register is set.
Cleared by hardware when reading KBF SFR by software.
6 KBF6
Keyboard line 6 flag
Set by hardware when the Port line 6 detects a programmed level. It generates a
Keyboard interrupt request if the KBIE.6 bit in KBIE register is set.
Cleared by hardware when reading KBF SFR by software.
5 KBF5
Keyboard line 5 flag
Set by hardware when the Port line 5 detects a programmed level. It generates a
Keyboard interrupt request if the KBIE.5 bit in KBIE register is set.
Cleared by hardware when reading KBF SFR by software.
4 KBF4
Keyboard line 4 flag
Set by hardware when the Port line 4 detects a programmed level. It generates a
Keyboard interrupt request if the KBIE.4 bit in KBIE register is set.
Cleared by hardware when reading KBF SFR by software.
3 KBF3
Keyboard line 3 flag
Set by hardware when the Port line 3 detects a programmed level. It generates a
Keyboard interrupt request if the KBIE.3 bit in KBIE register is set.
Cleared by hardware when reading KBF SFR by software.
2 KBF2
Keyboard line 2 flag
Set by hardware when the Port line 2 detects a programmed level. It generates a
Keyboard interrupt request if the KBIE.2 bit in KBIE register is set.
Cleared by hardware when reading KBF SFR by software.
1 KBF1
Keyboard line 1 flag
Set by hardware when the Port line 1 detects a programmed level. It generates a
Keyboard interrupt request if the KBIE.1 bit in KBIE register is set.
Cleared by hardware when reading KBF SFR by software.
0 KBF0
Keyboard line 0 flag
Set by hardware when the Port line 0 detects a programmed level. It generates a
Keyboard interrupt request if the KBIE.0 bit in KBIE register is set.
Cleared by hardware when reading KBF SFR by software.