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BASIC TIMER S3C8275X/F8275X/C8278X/F8278X/C8274X/F8274X
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 set 1,
address D3H, 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
f
xx/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 (set 1, bank 0, FDH), can be cleared at any time during normal operation by
writing a "1" to BTCON.1. To clear the frequency dividers for all timers input clock, you write a "1" to BTCON.0.
Basic Timer Control Register (BTCON)
D3H, Set 1, R/W
.7 .6 .5 .4 .3 .2 .1 .0MSB LSB
Divider clear bit for all timers:
0 = No effect
1 = Clear divider
Basic timer counter clear bit:
0 = No effect
1 = Clear BTCNT
Basic timer input clock selection bits:
00 = f
XX
/4096
01 = f
XX
/1024
10 = f
XX
/128
11 = f
XX
/16
Watchdog function enable bits:
1010B
Other values
= Disable watchdog timer
= Enable watchdog timer
Figure 10-1. Basic Timer Control Register (BTCON)