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5. Watchdog Timer (WDT)
5.3 Functions
TMP89FM42
RA000
Note:The 8-bit up counter source clock operates out of synchronization with WDCTR<WDTEN>. Therefore, the first
overflow time of the 8-bit up counter after WDCTR<WDTEN> is set to "1" may get shorter by a maximum of 1
source clock. The 8-bit up counter must be cleared within the period of the overflow time minus 1 source clock
cycle.
5.3.2
Setting the clear time of the 8-bit up counter
WDCTR<WDTW> sets the clear time of the 8-bit up counter.
When WDCTR<WDTW> is "00", the clear time is equal to the overflow time of the 8-bit up counter, and the
8-bit up counter can be cleared at any time.
When WDCTR<WDTW> is not "00", the clear time is fixed to only a certain period within the overflow
time of the 8-bit up counter. If the operation for releasing the 8-bit up counter is attempted outside the clear
time, a watchdog timer interrupt request signal occurs.
At this time, the watchdog timer is not cleared but continues counting. If the 8-bit up counter is not cleared
within the clear time, a watchdog timer reset request signal or a watchdog timer interrupt request signal occurs
due to the overflow, depending on the WDCTR<WDTOUT> setting.
Figure 5-3 WDCTR<WDTW> and the 8-bit up Counter Clear Time
5.3.3
Setting the overflow time of the 8-bit up counter
WDCTR<WDTT> sets the overflow time of the 8-bit up counter.
When the 8-bit up counter overflows, a watchdog timer reset request signal or a watchdog timer interrupt
request signal occurs, depending on the WDCTR<WDTOUT> setting.
If the watchdog timer interrupt request signal is selected as the malfunction detection signal, the watchdog
counter continues counting, even after the overflow has occurred.
The watchdog timer temporarily stops counting up in the STOP mode (including warm-up) or in the IDLE/
SLEEP mode, and restarts counting up after the STOP/IDLE/SLEEP mode is released. To prevent the 8-bit up
counter from overflowing immediately after the STOP/IDLE/SLEEP mode is released, it is recommended to
clear the 8-bit up counter before the operation mode is changed.
Table 5-1 Watchdog Timer Overflow Time (fcgck=10.0 MHz; fs=32.768 kHz)
WDTT
Watchdog timer overflow time [s]
NORMAL mode
SLOW
mode
DV9CK = 0
DV9CK = 1
00
26.21 m
62.50 m
62.50 m
01
104.86 m
250.00 m
250.00 m
10
419.43 m
1.000
1.000
11
1.678
4.000
4.000
When WDCTR<WDTW> is 00
8-bit up counter value
When WDCTR<WDTW> is 01
When WDCTR<WDTW> is 10
When WDCTR<WDTW> is 11
00H
01H
3FH 40H
7FH 80H
BFH C0H
FFH 00H
FFH
Clear time
Clear time
Outside the clear time
Clear time
Outside the clear time
Clear time
Outside the clear time
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: ......