
System Control Module (SCM)
Freescale Semiconductor
11-9
11.2.6
Core Watchdog Service Register (CWSR)
The software watchdog service sequence must be performed using the CWSR as a data register to prevent
a CWT time-out. The service sequence requires two writes to this data register: first a write of 0x55
followed by a write of 0xAA. Both writes must be performed in this order prior to the CWT time-out, but
any number of instructions can be executed between the two writes. If the CWT has already timed out,
writing to this register has no effect in negating the CWT interrupt or reset.
illustrates the
CWSR. At system reset, the contents of CWSR are uninitialized.
NOTE
If the CWT is enabled and has not timed out, then any write of a data value
other than 0x55 or 0xAA causes an immediate system reset, regardless of
the value in the CWCR[CWRI] field.
8
CWRWH
Core watchdog run while halted.
0 Core watchdog timer stops counting if the core is halted.
1 Core watchdog timer continues to count even while the core is halted.
7
CWE
Core watchdog timer enable.
0 CWT is disabled.
1 CWT is enabled.
6–5
CWRI
Core watchdog reset/interrupt.
00 If a time-out occurs, the CWT generates an interrupt to the core. Refer to
Chapter 14, “Interrupt Controller
for details on setting its priority level.
01
The first time-out generates an interrupt to the processor, and if not serviced, a second time-out
generates a system reset and sets theRSR[WDRCORE] flag in the reset controller.
10 If a time-out occurs, the CWT generates a system reset and
RSR[WDRCORE]
in the reset controller is set.
11 The CWT functions in a “window” mode of operation. For this mode, the servicing of the CWSR must occur during
the last 25% of the time-out period. Any writes to the CWSR during the first 75% of the time-out period generate
an immediate system reset. Likewise, if the CWSR is not serviced during the last 25% of the time-out period, a
system reset is generated. For any type of reset response, the
RSR[WDRCORE]
flag is set.
4–0
CWT
Core watchdog time-out period. Selects the time-out period for the CWT. At reset, this field is cleared selecting the
minimum time-out period, but the CWT is disabled since CWCR[CWE] = 0 at reset.
For CWCR[CWT] = n, time-out period = 2
n
system clock cycles, where n = 8–31. If n < 8, then time-out period is
forced to 2
8
.
Address: 0xFC04_001B (CWSR)
Access: User read/write
7
6
5
4
3
2
1
0
R
CWSR
W
Reset:
—
—
—
—
—
—
—
—
Figure 11-15. Core Watchdog Service Register (CWSR)
Table 11-7. CWCR Field Descriptions (continued)
Field
Description
MCF5329 Reference Manual, Rev 3
Содержание MCF5329
Страница 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 126: ...Enhanced Multiply Accumulate Unit EMAC 4 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 564: ...Liquid Crystal Display Controller LCDC 22 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 692: ...Programmable Interrupt Timers PIT0 PIT3 28 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 720: ...Queued Serial Peripheral Interface QSPI 30 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 790: ...Message Digest Hardware Accelerator MDHA 33 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 902: ...Register Memory Map Quick Reference A 26 Freescale Semiconductor MCF5329 Reference Manual Rev 3...