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BASIC TIMER and TIMER 0 S3F80JB
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 watch-dog timer function. It is located in Set 1 and
Bank0, address D3H, and is read/write addressable using register addressing mode.
A reset clears BTCON to '00H'. This enables the watch-dog function and selects a basic timer clock frequency of
fOSC/4096. To disable the watch-dog function, you must write the signature code '1010B' to the basic timer
register control bits BTCON.7–BTCON.4. For improved reliability, using the watch-dog timer function is
recommended in remote controllers and hand-held product applications.
Basic Timer Control Register (BTCON)
D3H, Set 1, Bank 0 , R/W
.7 .6 .5 .4 .3 .2 .1 .0MSB LSB
Divider Clear Bit for BT and T0:
0 = No effect
1 = Clear both dividers
Basic Timer Counter Clear Bits:
0 = No effect
1 = Clear BTCNT
Watch-dog Timer Enable Bits:
1010B = Disable watch-dog function
Others = Enable watch-dog function
Basic Timer Input Clock Selection Bits:
00 = f
OSC
/4096
01 = f
OSC
/1024
10 = f
OSC
/128
11 = Invalid selection
Figure 10-1. Basic Timer Control Register (BTCON)