Samsung 8-Bit CMOS Microcontroller Microcassette Recorder User Manual


 
BASIC TIMER S3C9228/P9228 (Preliminary Spec)
10-2
BASIC TIMER CONTROL REGISTER (BTCON)
The basic timer control register, BTCON, is used to select the input clock frequency, to clear the basic timer
counter and frequency dividers, and to enable or disable the watchdog timer function. It is located in page 0,
address DCH, and is read/write addressable using Register addressing mode.
A reset clears BTCON to "00H". This enables the watchdog function and selects a basic timer clock frequency of
fxx/4096. To disable the watchdog function, you must write the signature code “1010B” to the basic timer register
control bits BTCON.7–BTCON.4.
The 8-bit basic timer counter, BTCNT (page 0, DDH), can be cleared at any time during normal operation by
writing a "1" to BTCON.1. To clear the frequency dividers for the basic timer input clock and timer counters, you
write a "1" to BTCON.0.
Basic TImer Control Register (BTCON)
DCH, R/W
.7 .6 .5 .4 .3 .2 .1 .0MSB LSB
Divider clear bit for basic timer
and timer counters:
0 = No effect
1 = Clear divider
Basic timer counter clear bit:
0 = No effect
1 = Clear BTCNT
Basic timer input clock selection bits:
00 = fXX/4096
01 = fXX/1024
10 = fXX/128
11 = fXX/16
Watchdog function enable bits:
1010B
Other Value
= Disable watchdog timer
= Enable watchdog timer
Figure 10-1. Basic Timer Control Register (BTCON)