Rainbow Electronics AT89C51SND1C - Manual (Page 56)

56
AT8xC51SND1C
4109E–8051–06/03
Registers Table 60. TCON Register
TCON (S:88h) – Timer/Counter Control Register
Reset Value = 0000 0000b
7 6 5 4 3 2 1 0
TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0
Bit
Number
Bit
Mnemonic Description
7 TF1
Timer 1 Overflow Flag
Cleared by hardware when processor vectors to interrupt routine.
Set by hardware on Timer/Counter overflow, when Timer 1 register overflows.
6 TR1
Timer 1 Run Control Bit
Clear to turn off Timer/Counter 1.
Set to turn on Timer/Counter 1.
5 TF0
Timer 0 Overflow Flag
Cleared by hardware when processor vectors to interrupt routine.
Set by hardware on Timer/Counter overflow, when Timer 0 register overflows.
4 TR0
Timer 0 Run Control Bit
Clear to turn off Timer/Counter 0.
Set to turn on Timer/Counter 0.
3 IE1
Interrupt 1 Edge Flag
Cleared by hardware when interrupt is processed if edge-triggered (see IT1).
Set by hardware when external interrupt is detected on INT1 pin.
2 IT1
Interrupt 1 Type Control Bit
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.
1 IE0
Interrupt 0 Edge Flag
Cleared by hardware when interrupt is processed if edge-triggered (see IT0).
Set by hardware when external interrupt is detected on
INT0 pin.
0 IT0
Interrupt 0 Type Control Bit
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.