SONIX SN8P2624 - 8.3.3 TC1 C Counting Register

SN8P2624
8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD Page 78 Version 0.3
8.3.3 TC1C COUNTING REGISTER
TC1C is an 8-bit counter register for TC1 interval time control.
0DDH Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
TC1C
TC1C7 TC1C6 TC1C5 TC1C4 TC1C3 TC1C2 TC1C1 TC1C0
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
After reset 0 0 0 0 0 0 0 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.
TC1CKS PWM1 ALOAD1 TC1OUT
N
TC1C valid
value
TC1C value
binary type
Remark
0 x x 256 0x00~0xFF 00000000b~11111111b Overflow per 256 count
1 0 0 256 0x00~0xFF 00000000b~11111111b Overflow per 256 count
1 0 1 64 0x00~0x3F xx000000b~xx111111b Overflow per 64 count
1 1 0 32 0x00~0x1F xxx00000b~xxx11111b Overflow per 32 count
0
1 1 1 16 0x00~0x0F xxxx0000b~xxxx1111b Overflow per 16 count
1 - - - 256 0x00~0xFF 00000000b~11111111b Overflow per 256 count
¾ Example: To set 10ms interval time for TC1 interrupt. TC1 clock source is Fcpu (TC1KS=0) and no PWM
output (PWM1=0). High clock is external 4MHz. Fcpu=Fosc/4. Select TC1RATE=010 (Fcpu/64).
TC1C initial value = N - (TC1 interrupt interval time * input clock)
= 256 - (10ms * 4MHz / 4 / 64)
= 256 - (10
-2
* 4 * 10
6
/ 4 / 64)
= 100
= 64H
The basic timer table interval time of TC1.
High speed mode (Fcpu = 4MHz / 4) Low speed mode (Fcpu = 32768Hz / 4)
TC1RATE TC1CLOCK
Max overflow interval One step = max/256 Max overflow interval One step = max/256
000 Fcpu/256 65.536 ms 256 us 8000 ms 31250 us
001 Fcpu/128 32.768 ms 128 us 4000 ms 15625 us
010 Fcpu/64 16.384 ms 64 us 2000 ms 7812.5 us
011 Fcpu/32 8.192 ms 32 us 1000 ms 3906.25 us
100 Fcpu/16 4.096 ms 16 us 500 ms 1953.125 us
101 Fcpu/8 2.048 ms 8 us 250 ms 976.563 us
110 Fcpu/4 1.024 ms 4 us 125 ms 488.281 us
111 Fcpu/2 0.512 ms 2 us 62.5 ms 244.141 us