Samsung KS57C2308 Manual page 247

KS57C2308/P2308/C2316/P2316
WATCH TIMER MODE REGISTER (WMOD)
The watch timer mode register WMOD is used to select specific watch timer operations. It is 8-bit write-only
addressable. An exception is WMOD bit 3 (the XT
A automatically sets WMOD.3 to the current input level of the subsystem clock, XT
RESET
low, if logic zero), and all other WMOD bits to logic zero.
F88H WMOD.3
F89H WMOD.7
In summary, WMOD settings control the following watch timer functions:
— Watch timer clock selection
— Watch timer speed control
— Enable/disable watch timer
— XT input level control
IN
— Buzzer frequency selection
— Enable/disable buzzer output
Bit Name Values
WMOD.7
WMOD.6
WMOD.5–.4 0
0
1
1
WMOD.3
WMOD.2
WMOD.1
WMOD.0
:
NOTE System clock frequency (fxx) is assumed to be 4.19 MHz; subsystem clock (fxt) is assumed to be 32.768 kHz.
WMOD.2 WMOD.1
"0" WMOD.5
(WMOD.0)
(WMOD.1)
(WMOD.2)
(WMOD.3)
(WMOD.4 and WMOD.5)
(WMOD.7)
Table 11-8. Watch Timer Mode Register (WMOD) Organization
0 Disable buzzer (BUZ) signal output
1 Enable buzzer (BUZ) signal output
0 Always logic zero
0 2 kHz buzzer (BUZ) signal output
1 4 kHz buzzer (BUZ) signal output
0 8 kHz buzzer (BUZ) signal output
1 16 kHz buzzer (BUZ) signal output
Input level to XT
0
Input level to XT
1
0 Disable watch timer; clear frequency dividing circuits
1 Enable watch timer
0 Normal mode; sets IRQW to 0.5 seconds
1 High-speed mode; sets IRQW to 3.91 ms
0 Select the system clock (fxx/128) as the watch timer clock (fw)
1 Select subsystem clock as watch timer clock (fw)
input level control bit) which is 1-bit read-only addressable.
IN
WMOD.0
WMOD.4
Function
pin is lo; 1-bit read only
IN
pin is high; 1-bit read only
IN
TIMERS and TIMER/COUNTERS
(high, if logic one;
IN
Address
F89H
F88H
11-25