Chapter 12 Timer/Counter
12-7
12.3.6 Watchdog
Timer
Mode
The Watchdog Timer mode is used to monitor system anomalies. The software periodically clears the
counter and judges an anomaly to exist if the counter is not cleared within a specified period of time.
Then, either the TX4925 is internally reset or an NMI is signaled to the TX49/H2 core. Set the Timer
mode field (TMTCR2.TMODE) of the Timer Control Register to “10” to set the timer to the Watchdog
Timer mode. This mode can only be used by Timer 2.
Use the Watchdog Reset bit (WR) of the Chip Configuration Register (CCFG) to select whether to
perform an internal reset or signal an NMI. Set this bit to “1” to select Watchdog Reset, or set it to “0”
to select NMI Signaling.
When the timer count reaches the value programmed in Compare Register A (TMCPRA2), the
Watchdog Timer TMCPRA Match Status bit in the Timer Interrupt Status Register (TMTISR2.TWIS) is
set. Either the watchdog timer reset or NMI is issued if the Timer Watchdog Enable bit in the Watchdog
Timer Mode Register (TMWTMR2.TWIE) is set.
When the watchdog timer reset is selected, the Watchdog Reset Status bit in the Chip Configuration
Register (CCFG.WDRST) is set. The entire TX4925 is initialized but the configuration registers.
There are three ways of stopping NMI signaling from being performed.
(1) Clear the Watchdog Timer Interrupt Status bit (TMTISR2.TWIS) of the timer Interrupt Status
Register.
(2) Clear the counter by writing “1” to the Watchdog Timer Clear bit (TMWTMR2.TWC) of the
Watchdog Timer Mode Register.
(3) Clear the Watchdog Timer Interrupt Enable bit (TMWTMR2.TWIE) while the Watchdog Timer
Disable bit (TMWTMR2.WDIS) is still set.
It is possible to stop the counter when in the Watchdog Timer mode by clearing the Timer Counter
Enable bit (TMTCR2.TCE) of the Timer Control Register while the Watchdog Timer Disable bit
(TMWTMR2.WDIS) of the Watchdog Timer Mode Register is set to “1”.
It is also possible to stop the counter by clearing the Counter Clock Divide Cycle Enable bit
(TMTCR2.CCDE) of the Timer Control Register when the internal clock is being used as the counter
clock.
It is not possible to directly write “0” to the Watchdog Timer Disable bit (TMWTMR2.WDIS). There
are two ways to clear this bit.
(1) Clear the Watchdog Timer Interrupt Enable bit (TMWTMR2.WDIS)
(2) Clear the Timer Counter Enable bit (TMTCR2.TCE) of the Timer Control Register
Содержание TMPR4925
Страница 1: ...64 Bit TX System RISC TX49 Family TMPR4925 Rev 3 0 ...
Страница 4: ......
Страница 15: ...Handling Precautions ...
Страница 16: ......
Страница 18: ...1 Using Toshiba Semiconductors Safely 1 2 ...
Страница 40: ...3 General Safety Precautions and Usage Considerations 3 18 ...
Страница 42: ...4 Precautions and Usage Considerations 4 2 ...
Страница 43: ...TMPR4925 ...
Страница 44: ......
Страница 54: ...Chapter 1 Features 1 8 ...
Страница 58: ...Chapter 2 Block Diagram 2 4 ...
Страница 88: ...Chapter 4 Address Mapping 4 12 ...
Страница 226: ...Chapter 8 DMA Controller 8 58 ...
Страница 260: ...Chapter 9 SDRAM Controller 9 34 ...
Страница 480: ...Chapter 15 Interrupt Controller 15 32 ...
Страница 554: ...Chapter 19 Real Time Clock RTC 19 8 ...
Страница 555: ...Chapter 20 Removed 20 1 20 Removed ...
Страница 556: ...Chapter 20 Removed 20 2 ...
Страница 564: ...Chapter 21 Extended EJTAG Interface 21 8 ...
Страница 580: ...Chapter 22 Electrical Characteristics 22 16 ...
Страница 586: ...Chapter 23 Pin Layout Package 23 6 23 2 Package Package Type Package Code 256 pin PBGA PBGA 4L P BGA256 2727 1 27A4 ...
Страница 588: ...Chapter 24 Usage Notes 24 2 ...
Страница 590: ...Appendix A TX49 H2 Core Supplement A 2 ...