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Section 3 Exception Handling
Rev. 6.00 Sep 12, 2006 page 61 of 526
REJ09B0326-0600
Reset by Watchdog Timer:
The watchdog timer counter (TCW) starts counting up when the
WDON bit is set to 1 in the watchdog timer control/status register (TCSRW). If TCW overflows,
the WRST bit is set to 1 in TCSRW and the chip enters the reset state. While the WRST bit is set
to 1 in TCSRW, when TCW overflows the reset state is cleared and reset exception handling
begins. The same reset exception handling is carried out as for input at the
RES
pin. For details on
the watchdog timer, see section 9.6, Watchdog Timer.
3.2.3
Interrupt Immediately after Reset
After a reset, if an interrupt were to be accepted before the stack pointer (SP: R7) was initialized,
PC and CCR would not be pushed onto the stack correctly, resulting in program runaway. To
prevent this, immediately after reset exception handling all interrupts are masked. For this reason,
the initial program instruction is always executed immediately after a reset. This instruction should
initialize the stack pointer (e.g. MOV.W #xx: 16, SP).
3.3 Interrupts
3.3.1 Overview
The interrupt sources include 12 external interrupts (IRQ
3
to IRQ
0
, INT
7
to INT
0
) and 21 internal
interrupts from on-chip peripheral modules. Table 3.2 shows the interrupt sources, their priorities,
and their vector addresses. When more than one interrupt is requested, the interrupt with the
highest priority is processed.
The interrupts have the following features:
•
Internal and external interrupts can be masked by the I bit in CCR. When the I bit is set to 1,
interrupt request flags can be set but the interrupts are not accepted.
•
IRQ
3
to IRQ
0
and INT
7
to INT
0
can be set independently to either rising edge sensing or falling
edge sensing.
Содержание F-ZTAT H8/3642A Series
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Страница 21: ...Rev 6 00 Sep 12 2006 page xix of xx Appendix E Product Code Lineup 522 Appendix F Package Dimensions 524 ...
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Страница 124: ...Section 5 Power Down Modes Rev 6 00 Sep 12 2006 page 102 of 526 REJ09B0326 0600 ...
Страница 188: ...Section 6 ROM Rev 6 00 Sep 12 2006 page 166 of 526 REJ09B0326 0600 ...
Страница 190: ...Section 7 RAM Rev 6 00 Sep 12 2006 page 168 of 526 REJ09B0326 0600 ...
Страница 298: ...Section 9 Timers Rev 6 00 Sep 12 2006 page 276 of 526 REJ09B0326 0600 ...
Страница 378: ...Section 12 A D Converter Rev 6 00 Sep 12 2006 page 356 of 526 REJ09B0326 0600 ...
Страница 446: ...Section 13 Electrical Characteristics Rev 6 00 Sep 12 2006 page 424 of 526 REJ09B0326 0600 ...