King Billion Electronics Co., Ltd.
HE89C21
駿 億 電 子 股 份 有 限 公 司
HE80000 SERIES
controls enable or disable of the circuit.
OP2
Field
Mode
Reset
Bit 7
Bit 6
Bit 5
Bit 4
TBE
R/W
0
Bit 3
Bit 2
Bit 1
Bit 0
IDLE PNWK TCWK
TBS[3..0]
R/W
0
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
R/W
-
TBE Function
0
1
Disable Time Base
Enable Time Base
For example, if the slow clock is 32768 Hz, then the interrupt frequency is as shown in following table.
TBS[3..0] Interrupt Frequency
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
16.384 KHz
8.192 KHz
4.096 KHz
2.048 KHz
1.024 KHz
512 Hz
256 Hz
128 Hz
64 Hz
32 Hz
16 Hz
8 Hz
4 Hz
2 Hz
1 Hz
0.5 Hz
12. Watch Dog Timer
Watch Dog Timer (WDT) is designed to reset system automatically prevent system dead lock caused by
abnormal hardware activities or program execution. WDT needs to be enabled in Mask Option.
MO_WDTE Function
0
1
WDT disable
WDT enable
To use WDT function, “CLRWDT” instruction needs to be executed in every possible program path
when the program runs normally in order to clears the WDT counter before it overflows, so that the
program can operate normally. When abnormal conditions happen to cause the MCU to divert from
normal path, the WDT counter will not be cleared and reset signal will be generated.
January 20, 2003
12
V1.0E
KB [ King blillion Electronics Co.,Ltd. ]
