Page 75
TMP89FM42
RA000
Note 1: WDST<WINTST2> and WDST<WINTST1> are cleared to "0" by reading WDST.
Note 2: Values after reset are read from bits 7 to 3 of WDST.
5.3
Functions
The watchdog timer can detect the CPU malfunctions and deadlock by detecting the overflow of the 8-bit up
counter and detecting releasing of the 8-bit up counter outside the clear time.
The watchdog timer stoppage and other abnormalities can be detected by reading the count value of the 8-bit up
counter at random times and comparing the value to the last read value.
5.3.1
Setting of enabling/disabling the watchdog timer operation
Setting WDCTR<WDTEN> to "1" enables the watchdog timer operation, and the 8-bit up counter starts
counting the source clock.
WDCTR<WDTEN> is initialized to "1" after the warm-up operation that follows reset is released. This
means that the watchdog timer is enabled.
To disable the watchdog timer operation, clear WDCTR<WDTEN> to "0" and write 0xB1 into WDCDR.
Disabling the watchdog timer operation clears the 8-bit up counter to "0".
Note:If the overflow of the 8-bit up counter occurs at the same time as 0xB1 (disable code) is written into WDCDR
with WDCTR<WDTEN> set at "1", the watchdog timer operation is disabled preferentially and the overflow
detection is not executed.
To re-enable the watchdog timer operation, set WDCTR<WDTEN> to "1". There is no need to write a con-
trol code into WDCDR.
Figure 5-2 WDCTR<WDTEN> Set Timing and Overflow Time
Watchdog timer status
WDST
(0x0FD7)
7
6
5
4
3
2
1
0
Bit Symbol
-
-
-
-
-
WINTST2
WINTST1
WDTST
Read/Write
R
R
R
R
R
R
R
R
After reset
0
1
0
1
1
0
0
1
WINTST2
Watchdog timer interrupt request
signal factor status 2
0 :
1 :
No watchdog timer interrupt request signal has occurred.
A watchdog timer interrupt request signal has occurred due to the over-
flow of the 8-bit up counter.
WINTST1
Watchdog timer interrupt request
signal factor status 1
0 :
1 :
No watchdog timer interrupt request signal has occurred.
A watchdog timer interrupt request signal has occurred due to releasing of
the 8-bit up counter outside the clear time.
WDTST
Watchdog timer operating state sta-
tus
0 :
1 :
Operation disabled
Operation enabled
8-bit up counter value
Watchdog timer source clock
WDCTR<WDTEN>
00H
01H
FFH
WDCTR<WDTEN>
Interrupt request signal
00H
Overflow time
Overflow time
1 clock (max.)
Summary of Contents for TLCS-870/C1 Series
Page 1: ...8 Bit Microcontroller TLCS 870 C1 Series TMP89FM42 查询TMP89FM42供应商 捷多邦 专业PCB打样工厂 24小时加急出货 ...
Page 3: ...Revision History Date Revision 2007 10 25 1 First Release 2007 11 3 2 Contents Revised ...
Page 4: ......
Page 14: ......
Page 18: ...1 3 Block Diagram TMP89FM42 1 3 Block Diagram Figure 1 2 Block Diagram ...
Page 22: ...1 4 Pin Names and Functions TMP89FM42 ...
Page 60: ...2 CPU Core 2 5 Revision History TMP89FM42 ...
Page 76: ...3 Interrupt Control Circuit 3 8 Revision History TMP89FM42 ...
Page 86: ...4 External Interrupt control circuit 4 3 Function TMP89FM42 ...
Page 102: ...7 Voltage Detection Circuit 7 5 Revision History TMP89FM42 ...
Page 126: ...8 I O Ports 8 3 I O Port Registers TMP89FM42 Note 2 i 0 to 1 ...
Page 136: ...8 I O Ports 8 5 Revision History TMP89FM42 ...
Page 142: ...9 Special Function Registers 9 3 SFR3 0x0E40 to 0x0EFF TMP89FM42 ...
Page 146: ...10 Low Power Consumption Function for Peripherals TMP89FM42 ...
Page 149: ...TMP89FM42 11 3 Revision History Rev Description RA001 Deleted SLEEP2 description ...
Page 150: ...11 Divider Output DVO 11 3 Revision History TMP89FM42 ...
Page 220: ...15 Real Time Clock RTC 15 4 Real Time Clock Operation TMP89FM42 ...
Page 250: ...16 Asynchronous Serial Interface UART 16 15 Revision History TMP89FM42 ...
Page 302: ...18 Serial Bus Interface SBI 18 7 Revision History TMP89FM42 ...
Page 338: ...21 Flash Memory 21 4 Toggle Bit D6 TMP89FM42 ...
Page 384: ...22 Serial PROM Mode 22 15 Revision History TMP89FM42 ...
Page 388: ...24 Input Output Circuit 24 1 Control Pins TMP89FM42 ...
Page 404: ...25 Electrical Characteristics 25 11 Revision History TMP89FM42 ...
Page 406: ...26 Package Dimensions TMP89FM42 ...
Page 408: ......