MMC2107 - Freescale Semiconductor

Freescale Semiconductor, Inc.
Watchdog Timer Module
Memory Map and Registers
13.6.2.4 Watchdog Service Register
When the watchdog timer is enabled, writing 0x5555 and then 0xAAAA
to the watchdog service register (WSR) before the watchdog counter
times out prevents a reset. If WSR is not serviced before the timeout, the
watchdog timer sends a signal to the reset controller module which sets
the WDR bit and asserts a system reset.
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Freescale Semiconductor, I
Both writes must occur in the order listed before the timeout, but any
number of instructions can be executed between the two writes.
However, writing any value other than 0x5555 or 0xAAAA to WSR resets
the servicing sequence, requiring both values to be written to keep the
watchdog timer from causing a reset.
Address: 0x00c7_0006 and 0x00c7_0007
Read:
Write:
Bit 15 14 13 12 11 10 9 Bit 8
WS15 WS14 WS13 WS12 WS11 WS10 WS9 WS8
Reset: 0 0 0 0 0 0 0 0
Read:
Write:
Bit 7 6 5 4 3 2 1 Bit 0
WS7 WS6 WS5 WS4 WS3 WS2 WS1 WS0
Reset: 0 0 0 0 0 0 0 0
Figure 13-5. Watchdog Service Register (WSR)
MMC2107 – Rev. 2.0
Technical Data
MOTOROLA Watchdog Timer Module 279
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