Samsung KS57C2308 Manual page 241

KS57C2308/P2308/C2316/P2316
TC0 COUNTER REGISTER (TCNT0)
The 8-bit counter register for timer/counter 0, TCNT0, is read-only and can be addressed by 8-bit RAM control
instructions. sets all TCNT0 register values to logic zero (00H).
RESET
Whenever TMOD0.3 is enabled, TCNT0 is cleared to logic zero and counting resumes. TCNT0 register value is
incremented at the selected edge each time an incoming pulse with reference clock specified by TMOD0 register
(specifically, TMOD0.6, TMOD0.5, and TMOD0.4) is input.
Each time TCNT0 is incremented, the new value is compared with the reference value stored in the TC0
reference buffer, TREF0. When TCNT0 = TREF0, an match signal occurs in the comparator, the interrupt
request flag, IRQT0, is set to logic one, and an interrupt request is generated to indicate that the specified
timer/counter interval has elapsed.
COUNT
CLOCK
TREF0
TCNT0 0
TOL0
TIMER START INSTRUCTION
(TMOD0.3 IS SET)
1 2 n-1 n
IRQT0 SET
Figure 11-3. TC0 Timing Diagram
REFERENCE VALUE = n
0 1 2
MATCH
INTERVAL TIME
TIMERS and TIMER/COUNTERS
n-1 n 0 1
MATCH
IRQT0 SET
2 3
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