TOSHIBA
TMPR3904F Rev. 2.0
215
13.4.3 Watchdog timer mode
In the TX3904, only the watchdog timer interrupt request signal (WDTINTREQ*) of the
timer/counter Channel 2 can be connected to the internal NMI* or the reset circuit. The
connection target of the WDTINTREQ* signal is selected in the WR bit of the chip
configuration register CConR.
When the TMODE of the TCR2 is 10, it is the watchdog mode. When the TCE of the TCR2 is
set to 1, the 24-bit counter starts counting. When the count value matches the CPRA, the
comparator hoists a flag (“1”) to the timer watchdog interrupt status (TWIS) of the TISR2. The
interrupt control logic asserts the watchdog timer interrupt request WDTINTREQ* when 1 is set
to the timer watchdog interrupt enable (TWIE) of the TCRn. When 0 is set to the TWIE, the
WDTINTREQ* shall not be asserted. The WDTINTREQ* is deasserted by writing “0” into the
TWIS. The writing-in of “1” to the TWIS shall be ignored. When 1 is set to the timer
watchdog clear (TWC) of the watchdog timer mode register 2 (WTMR2), the 24-bit count shall
be cleared. The TWC shall be cleared to 0 automatically after the 24-bit counter clears.
The watchdog timer can be disabled (counter halted) by setting the TCE to 0 when the watchdog
timer disable (WDIS) of the WTMR2 is set to 1. When the WDIS is 0, the count operation
cannot be halted even if the TCE is set to 0. If the TWIE of the TISR2 is set to 0 while WDIS is
1, the watchdog timer can also be disabled (interrupt masking). The TWIE cannot be set to 0
when the WDIS is 0. The WDIS shall automatically be cleared to 0 when the watchdog timer
has become disabled by one of the above methods.
The count value can be read by reading the TRR2.
C o u n t V a l u e
0 x 0 0 0 0 0 0
C o m p a r e V a l u e
T M O D E = 1 0
T C E = 1
T W I E = 1
W D T I N T R E Q *
T i m e
T W C = 1
T W I E = 0
R e s e t S t a t e
T W I E = 1
T M O D E = 1 0
T C E = 1
T W I E = 1
C P R A
T W C = 1
W D I S = 1
R e s e t S t a t e
T W C = 1
T C E = 0
W D I S = 1
T C E = 1
C R E = 0
T W I S = 1
T W I S = 0
T W I S = 1
Fig. 13-17 Watchdog Timer Mode Operation
Summary of Contents for TMPR3904F
Page 1: ...Users Manual 32bit RISC Microprocessor TX39 family TMPR3904F Rev 2 0 Jan 12 1998 ...
Page 2: ......
Page 9: ...Users Manual 01 1 INTRODUCTION 1 1 Overview ...
Page 11: ...Users Manual 03 1 3 Kind of accessing by the TX3904 ...
Page 12: ...Users Manual 04 1 4 Precautions in the TMPR3904F specification Don t set Don t use ...
Page 13: ...Users Manual 05 Do not use ...
Page 14: ...Users Manual 06 ...
Page 15: ...Users Manual 7 2 FEATURES n n n n n n n n n n n n n ...
Page 16: ...Users Manual 8 ...
Page 18: ...Users Manual 10 ...
Page 19: ...Users Manual 11 4 PINS 4 1 Positions of Pins ...
Page 20: ...Users Manual 12 ...
Page 21: ...Users Manual 13 4 2 Functions of Pins ...
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Page 26: ...Users Manual 18 5 2 Register Map ...
Page 27: ...Users Manual 19 ...
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Page 30: ...Users Manual 22 5 3 2 PIO2 and PIO1 ...
Page 32: ...Users Manual 24 5 3 4 Connection of external bus master 5 3 5 INT 7 0 active status clear ...
Page 33: ...Users Manual 25 5 3 6 INT 7 0 active status set up ...
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