AT89C51RE2 Atmel Corporation, AT89C51RE2 Datasheet - Page 128

• Manufacturer Part Number: AT89C51RE2
• Manufacturer: Atmel Corporation

Specifications of AT89C51RE2

• Flash (kbytes): 128 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Spi: 1
• Uart: 2
• Sram (kbytes): 8.25
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART/OCD
• Watchdog: Yes

Registers
128
AT89C51RE2
Table 95. KBF Register
KBF-Keyboard Flag Register (9Eh)
Reset Value= 0000 0000b
Bit Number
KBF7
7
7
6
5
4
3
2
1
0
Mnemonic
KBF6
KBF7
KBF6
KBF5
KBF4
KBF3
KBF2
KBF1
KBF0
Bit
6
Description
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.
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.
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.
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.
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.
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.
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.
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.
KBF5
5
KBF4
4
KBF3
3
KBF2
2
KBF1
1
7663E–8051–10/08
KBF0
0