SN8F2250B Series
USB 2.0 Full-Speed 8-Bit Micro-Controller
8.6.3 TC1C COUNTING REGISTER
TC1C is an 8-bit counter register for TC1 interval time control.
08CH
TC1C
Read/Write
After reset
Bit 7
TC1C7
R/W
0
Bit 6
TC1C6
R/W
0
Bit 5
TC1C5
R/W
0
Bit 4
TC1C4
R/W
0
Bit 3
TC1C3
R/W
0
Bit 2
TC1C2
R/W
0
Bit 1
TC1C1
R/W
0
Bit 0
TC1C0
R/W
0
The equation of TC1C initial value is as following.
TC1C initial value = N - (TC1 interrupt interval time * input clock)
N is TC1 overflow boundary number. TC1 timer overflow time has six types (TC1 timer, TC1 event counter, TC1 Fcpu
clock source, TC1 Fosc clock source, PWM mode and no PWM mode). These parameters decide TC1 overflow time
and valid value as follow table.
TC1C valid
value
TC1C value
binary type
TC1CKS PWM0 ALOAD0 TC1OUT
Remark
N
0
1
1
1
1
-
x
0
0
1
1
-
x
0
1
0
1
-
256
256
64
32
16
0x00~0xFF 00000000b~11111111b
0x00~0xFF 00000000b~11111111b
Overflow per 256 count
Overflow per 256 count
Overflow per 64 count
Overflow per 32 count
Overflow per 16 count
Overflow per 256 count
0
1
0x00~0x3F
0x00~0x1F
0x00~0x0F
xx000000b~xx111111b
xxx00000b~xxx11111b
xxxx0000b~xxxx1111b
256
0x00~0xFF 00000000b~11111111b
¾
Example: To set 1ms interval time for TC1 interrupt. TC1 clock source is Fcpu (TC1KS=0) and no PWM
output (PWM0=0). High clock is internal 6MHz. Fcpu=Fosc/1. Select TC1RATE=010 (Fcpu/64).
TC1C initial value = N - (TC1 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 TC1.
High speed mode (Fcpu = 6MHz / 1)
TC1RATE TC1CLOCK
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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