Samsung S3C9228/P9228, 8-Bit CMOS Microcontroller user manual Basic Timer Control Register Btcon

BASIC TIMER S3C9228/P9228 (Preliminary Spec)

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.

MSB

Basic TImer Control Register (BTCON)

DCH, R/W

.7 .6 .5 .4 .3 .2 .1 .0

LSB

Watchdog function enable bits:

1010B = Disable watchdog timer Other Value = Enable watchdog timer

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

Figure 10-1. Basic Timer Control Register (BTCON)

10-2