Datasheet

65
AT89C51RB2/RC2
4180D–8051–06/05
Registers Table 51. KBF Register
KBF - Keyboard Flag Register (9Eh)
Reset Value = 0000 0000b
This register is read only access, all flags are automatically cleared by reading the
register.
76543210
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.
Must be cleared 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.
Must be cleared 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.
Must be cleared 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.
Must be cleared 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.
Must be cleared 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.
Must be cleared 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.
Must be cleared 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.
Must be cleared by software.