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S3C8248/C8245/P8245/C8247/C8249/P8249
BASIC TIMER
10
BASIC TIMER
OVERVIEW
S3C8248/C8245/C8247/C8249 has an 8-bit basic timer .
BASIC TIMER (BT)
You can use the basic timer (BT) in two different ways:
— As a watchdog timer to provide an automatic reset mechanism in the event of a system malfunction, or
— To signal the end of the required oscillation stabilization interval after a reset or a Stop mode release.
The functional components of the basic timer block are:
— Clock frequency divider (f
divided by 4096, 1024, 128, or 16) with multiplexer
xx
— 8-bit basic timer counter, BTCNT (set 1, Bank 0, FDH, read-only)
— Basic timer control register, BTCON (set 1, D3H, read/write)
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
/4096. To disable the watchdog function, you must write the signature code "1010B" to the basic timer register
xx
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 the normal
operation by writing a "1" to BTCON.1. To clear the frequency dividers, write a "1" to BTCON.0.
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