ABOV SEMICONDUCTOR MC81F4204 - Basic Interval Timer Interrupt Periods

MC81F4204
April 24, 2012 Ver.1.41 91
14.1 Registers
CKCTLR
CLOCK CONTROL REGISTER 00F2H
7 6 5 4 3 2 1 0
CKCTLR
– – – WDTON BTCL BTS
Reset value: 17H
– – – R/W R/W R/W R/W R/W
– bit7 – bit5 Not used for MC81F4204
0: Operate as 7-bit timer
WDTON
Watchdog Timer Enable Bit
1: Enable Watchdog timer
0: Normal operation (free-run)
BTCL
Basic Timer Clear Bit
1: Clear 8-bit counter (BITR) to “0”,
This bit becomes 0 automatically after one
machine cycle, and starts counting.
000: fxin/8
001: fxin/16
010: fxin/32
011: fxin/64
100: fxin/128
101: fxin/256
110: fxin/512
BTS
Basic Interval Timer Source Clock
Selection Bits
111: fxin/1024
CKCTLR[2:0] Source clock
Interrupt(overflow) period (ms)
@ fxin = 8MHz
000 fxin/8 0.256
001 fxin/16 0.512
010 fxin/32 1.024
011 fxin/64 2.048
100 fxin/128 4.096
101 fxin/256 8.192
110 fxin/512 16.384
111 fxin/1024 32.768
BTCR
BASIC TIMER COUNTER REGISTER 00F1H
7 6 5 4 3 2 1 0
BTCR
One byte register
Reset value: XXH
R R R R R R R R
Figure 14-1 Basic Interval Timer Interrupt Period