User’s Manual
7-6
05.99
Interrupt System
C513AO
Special Function Register TCON (Address 88H)
Reset Value: 00H
Bit
Function
TF1
Timer 1 overflow flag
Set by hardware on Timer/Counter 1 overflow. Cleared by hardware when the
processor vectors to the interrupt routine.
TF0
Timer 0 overflow flag
Set by hardware on Timer/Counter 0 overflow. Cleared by hardware when the
processor vectors to the interrupt routine.
IE1
External interrupt 1 request flag
Set by hardware. Cleared by hardware when the processor vectors to the interrupt
routine (if IT1 = 1) or released by external source (if IT1 = 0).
IT1
External interrupt 1 level/edge-trigger control flag
If IT1 = 0, level triggered external Interrupt 1 is selected.
If IT1 = 1, negative edge-triggered external Interrupt 1 is selected.
IE0
External interrupt 0 request flag
Set by hardware. Cleared by hardware when the processor vectors to the interrupt
routine (if IT0 = 1) or released by external source (if IT0 = 0).
IT0
External interrupt 0 level/edge trigger control flag
If IT0 = 0, level triggered external interrupt 0 is selected.
If IT0 = 1, negative edge-triggered external Interrupt 0 is selected.
TF1
TR1
TF0
TR0
88H
TCON
Bit No.
8F
H
MSB
LSB
IE1
IT1
IE0
IT0
8E
H
8D
H
8C
H
8B
H
8A
H
89
H
88
H
The shaded bits are not used for interrupt request control.