SN8P1600
8-bit micro-controller
TC0C COUNTING REGISTER
TC0C is an 8-bit counter register for the timer (TC0). TC0C must be reset whenever the TC0ENB is set to “1” to start
the timer. TC0C is incremented each time a clock pulse of the frequency determined by TC0RATE0 ~ TC0RATE2.
When TC0C has incremented to “0FFH”, it counts to “00H” an overflow generated. Under TC0 interrupt service request
(TC0IEN) enable condition, the TC0 interrupt request flag will be set to “1” and the system executes the interrupt
service routine. The TC0C has no auto reload function. After TC0C overflow, the TC0C is continuing counting. Users
need to reset TC0C value to get an accurate time.
0DBH
TC0C
Read/Write
After reset
Bit 7
TC0C7
R/W
0
Bit 6
TC0C6
R/W
0
Bit 5
TC0C5
R/W
0
Bit 4
TC0C4
R/W
0
Bit 3
TC0C3
R/W
0
Bit 2
TC0C2
R/W
0
Bit 1
TC0C1
R/W
0
Bit 0
TC0C0
R/W
0
The basic timer table interval time of TC0.
High speed mode (fcpu = 3.58MHz / 4)
Low speed mode (fcpu = 32768Hz / 4)
Max overflow interval One step = max/256 Max overflow interval One step = max/256
TC0RATE TC0CLOCK
000
001
010
011
100
101
110
111
fcpu/256
fcpu/128
fcpu/64
fcpu/32
fcpu/16
fcpu/8
73.2 ms
36.6 ms
18.3 ms
9.15 ms
4.57 ms
2.28 ms
1.14 ms
0.57 ms
286us
143us
71.5us
35.8us
17.9us
8.94us
4.47us
2.23us
8000 ms
4000 ms
2000 ms
1000 ms
500 ms
250 ms
125 ms
62.5 ms
31.25 ms
15.63 ms
7.8 ms
3.9 ms
1.95 ms
0.98 ms
0.49 ms
0.24 ms
fcpu/4
fcpu/2
The equation of TC0C initial value is as following.
TC0C initial value = 256 - (TC0 interrupt interval time * input clock)
ꢃ
Example: To set 10ms interval time for TC0 interrupt at 3.58MHz high-speed mode. TC0C value (74H) =
256 - (10ms * fcpu/64)
TC0C initial value = 256 - (TC0 interrupt interval time * input clock)
= 256 - (10ms * 3.58 * 106 / 4 / 64)
= 256 - (10-2 * 3.58 * 106 / 4 / 64)
= 116
= 74H
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