17.3.4 Using interrupts to delay resets
When interrupts are enabled (CS1[INT] = 1), the watchdog first generates an interrupt
request upon a reset triggering event (such as a counter timeout or invalid refresh
attempt). The watchdog delays forcing a reset for 128 bus clocks to allow the interrupt
service routine (ISR) to perform tasks, such as analyzing the stack to debug code.
When interrupts are disabled (CS1[INT] = 0), the watchdog does not delay forcing a
reset.
17.3.5 Backup reset
NOTE
A clock source other than the bus clock must be used as the
reference clock for the counter; otherwise, the backup reset
function is not available.
The backup reset function is a safeguard feature that independently generates a reset in
case the main WDOG logic loses its clock (the bus clock) and can no longer monitor the
counter. If the watchdog counter overflows twice in succession (without an intervening
reset), the backup reset function takes effect and generates a reset.
17.3.6 Functionality in debug and low-power modes
By default, the watchdog is not functional in Active Background mode, Wait mode, or
Stop3 mode. However, the watchdog can remain functional in these modes as follows:
• For Active Background mode, set CS1[DBG]. (This way the watchdog is functional
in Active Background mode even when the CPU is held by the Debug module.)
• For Wait mode, set CS1[WAIT].
• For Stop3 mode, set CS1[STOP].
NOTE
The watchdog can not generate interrupt in Stop3 mode even if
CS1[STOP] is set and will not wake the MCU from Stop3
mode. It can generate reset during Stop3 mode.
Functional description
MC9S08PA4 Reference Manual, Rev. 5, 08/2017
348
NXP Semiconductors
Содержание MC9S08PA4
Страница 1: ...MC9S08PA4 Reference Manual Supports MC9S08PA4 Document Number MC9S08PA4RM Rev 5 08 2017 ...
Страница 2: ...MC9S08PA4 Reference Manual Rev 5 08 2017 2 NXP Semiconductors ...
Страница 22: ...MC9S08PA4 Reference Manual Rev 5 08 2017 22 NXP Semiconductors ...
Страница 28: ...System clock distribution MC9S08PA4 Reference Manual Rev 5 08 2017 28 NXP Semiconductors ...
Страница 150: ...Port data registers MC9S08PA4 Reference Manual Rev 5 08 2017 150 NXP Semiconductors ...
Страница 196: ...Human machine interfaces HMI MC9S08PA4 Reference Manual Rev 5 08 2017 196 NXP Semiconductors ...
Страница 224: ...Instruction Set Summary MC9S08PA4 Reference Manual Rev 5 08 2017 224 NXP Semiconductors ...
Страница 232: ...Functional Description MC9S08PA4 Reference Manual Rev 5 08 2017 232 NXP Semiconductors ...
Страница 258: ...FTM Interrupts MC9S08PA4 Reference Manual Rev 5 08 2017 258 NXP Semiconductors ...
Страница 268: ...Initialization application information MC9S08PA4 Reference Manual Rev 5 08 2017 268 NXP Semiconductors ...
Страница 294: ...Functional description MC9S08PA4 Reference Manual Rev 5 08 2017 294 NXP Semiconductors ...
Страница 370: ...Memory map and register description MC9S08PA4 Reference Manual Rev 5 08 2017 370 NXP Semiconductors ...
Страница 398: ...Resets MC9S08PA4 Reference Manual Rev 5 08 2017 398 NXP Semiconductors ...
Страница 400: ...MC9S08PA4 Reference Manual Rev 5 08 2017 400 NXP Semiconductors ...