SN8F2270B Series
USB 2.0 Low-Speed 8-Bit Micro-Controller
8.2.3 T0C COUNTING REGISTER
T0C is an 8-bit counter register for T0 interval time control.
0D9H
T0C
Read/Write
After reset
Bit 7
T0C7
R/W
0
Bit 6
T0C6
R/W
0
Bit 5
T0C5
R/W
0
Bit 4
T0C4
R/W
0
Bit 3
T0C3
R/W
0
Bit 2
T0C2
R/W
0
Bit 1
T0C1
R/W
0
Bit 0
T0C0
R/W
0
The equation of T0C initial value is as following.
T0C initial value = 256 - (T0 interrupt interval time * input clock)
Example: To set 1ms interval time for T0 interrupt. High clock is 6MHz. Fcpu=Fosc/1. Select T0RATE=010
(Fcpu/64).
T0C initial value = 256 - (T0 interrupt interval time * input clock)
= 256 - (1ms * 6MHz / 1 / 64)
= 256 - (10-3 * 6 * 106 / 1 / 64)
= 162
= A2H
The basic timer table interval time of T0.
High speed mode (Fcpu = 6MHz)
T0RATE
T0CLOCK
Max overflow interval One step = max/256
000
001
010
011
100
101
110
111
Fcpu/256
Fcpu/128
Fcpu/64
Fcpu/32
Fcpu/16
Fcpu/8
10.923 ms
5.461 ms
2.731 ms
1.365 ms
0.683 ms
0.341 ms
0.171 ms
0.085 ms
42.67 us
21.33 us
10.67 us
5.33 us
2.67 us
1.33 us
0.67 us
0.33 us
Fcpu/4
Fcpu/2
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