
16-BIT TIMER 0 
S3C94A5/F94A5 
11-2 
T0CON is located in page 0, at address B4H, and is read/write addressable using register addressing mode. 
A reset clears T0CON to “00H”. This sets timer 0 to normal interval timer mode, selects an input clock frequency of 
fxx/1024, and disables all timer 0 interrupts. You can clear the timer 0 counter at any time during normal operation 
by writing a "1" to T0CON.2. 
To enable the timer 0 match/capture interrupt (T0INT), you must write T0CON.1 to "1". To detect a match/capture 
interrupt pending condition, the application program polls INTPND3.0. When a "1" is detected, a timer 0 match or 
capture interrupt is pending. When the interrupt request has been serviced, the pending condition must be cleared by 
software by writing a "0" to the timer 0 match/capture interrupt pending bit, INTPND3.0. 
Timer 0 Control Register (T0CON)
B4H, R/W
.7
.6
.5
.4
.3
.2
.1
.0
MSB
LSB
Timer 0 counter clear bit:
0 = No effect
1 = Clear the timer 0 counter (when write)
Timer 0 input clock selection bits:
000 = fxx/1024
001 = fxx/256
010 = fxx/64
011 = fxx/8
100 = fxx
101 = External clock
         (P3.5/T0CLK) falling edge
110 = External clock
         (P3.5/T0CLK) rising edge
111 = Counter stop
Timer 0 operating mode selection bits:
00 = Interval mode (P3.3/T0OUT)
01 = Capture mode (capture on rising edge,
        counter running, OVF can occur)
10 = Capture mode (capture on falling edge,
        counter running, OVF can occur)
11 = PWM mode (OVF and match interrupt can occur)
Timer 0 overflow interrupt enable bit:
0 = Disable overflow interrupt
1 = Enable overflow interrupt
Timer 0 match/capture interrupt enable bit:
0 = Disable interrupt
1 = Enable interrupt
Figure 11-1. Timer 0 Control Register (T0CON)