Syntek Semiconductor Co., Ltd
LCD Controller
5 / 5
ISSUE DATE : 3 March, 2000
STK55C641
In sleep mode 1, both of the main system oscillator and 32.768KHz sub-system
oscillator will be stopped. So, all function are stopped and only external interrupt can
wake up this chip. The LCD display will be turn off while getting into sleep mode 1.
In sleep mode 2, only main system oscillator will be stopped. So, the following
functions will still keep working.
* The LCD will be kept on.
* The watch timer and fix-time timer will keep going.
* The NMI, port 1, watch timer and fix-time timer interrupt will wake up this chip.
* CPU will keep working if clock source is 32.768K Hz.
1002 Watch timer control register. Write only.
Bit 0 : = 0 Set watch timer interrupt at 10 Hz
= 1 Set watch timer interrupt at 100 Hz
1 : = 0 Set fix-time timer interrupt at 2 Hz
= 1 Set fix-time timer interrupt at 1 Hz
2 : = 0 Normal operation.
= 1 Reset and stop stopwatch timer.
3 : = 0 Stop stopwatch register without reset.
= 1 Start stopwatch timer.
4 : = 0 CPU clock is system clock.
= 1 CPU clock is 32.768K Hz.
7-5 : Reserved.
The default value for each bit is zero. Bit 2 will be cleared to zero automatically after
stopwatch timer reset.
1003 IRQ flag register. Read & write.
Read function :
Bit 0 : = 1 Stopwatch timer interrupt, IRQ1.
1 : = 1 Fix-time timer interrupt, IRQ2.
2 : = 1 Timer interrupt, IRQ3.
3 : = 1 External interrupt, IRQ4.
Write function :
Bit 0 : = 0 Clear stopwatch timer interrupt.
1 : = 0 Clear fix-time timer interrupt.
2 : = 0 Clear timer interrupt.
3 : = 0 Clear external interrupt.
Note : Please do not use the STZ
$1003 to clear all the interrupts at the same time.