AT89C51RE2 Datasheet, PDF (73/187 Pages) ATMEL Corporation – 8-bit Flash Microcontroller

Registers
AT89C51RE2
Table 46. TCON Register
TCON (S:88h)
Timer/Counter Control Register
7
6
5
4
3
2
1
0
TF1
TR1
TF0
TR0
IE1
IT1
IE0
IT0
Bit
Bit Number Mnemonic Description
Timer 1 Overflow Flag
7
TF1
Cleared by hardware when processor vectors to interrupt routine.
Set by hardware on Timer/Counter overflow, when Timer 1 register overflows.
Timer 1 Run Control Bit
6
TR1 Clear to turn off Timer/Counter 1.
Set to turn on Timer/Counter 1.
Timer 0 Overflow Flag
5
TF0
Cleared by hardware when processor vectors to interrupt routine.
Set by hardware on Timer/Counter overflow, when Timer 0 register overflows.
Timer 0 Run Control Bit
4
TR0 Clear to turn off Timer/Counter 0.
Set to turn on Timer/Counter 0.
Interrupt 1 Edge Flag
3
IE1
Cleared by hardware when interrupt is processed if edge-triggered (see IT1).
Set by hardware when external interrupt is detected on INT1# pin.
Interrupt 1 Type Control Bit
2
IT1
Clear to select low level active (level triggered) for external interrupt 1 (INT1#).
Set to select falling edge active (edge triggered) for external interrupt 1.
Interrupt 0 Edge Flag
1
IE0
Cleared by hardware when interrupt is processed if edge-triggered (see IT0).
Set by hardware when external interrupt is detected on INT0# pin.
Interrupt 0 Type Control Bit
0
IT0
Clear to select low level active (level triggered) for external interrupt 0 (INT0#).
Set to select falling edge active (edge triggered) for external interrupt 0.
Reset Value = 0000 0000b
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