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System Control Module (SCM)
MCF52235 ColdFire® Integrated Microcontroller Reference Manual, Rev. 6
13-8
Freescale Semiconductor
IPSBAR
Offset: 0x0011 (CWCR)
Access: read/write
7
6
5
4
3
2
1
0
R
CWE
CWRI
CWT[2:0]
CWTA
CWTAVAL
CWTIF
W
Reset:
0
0
0
0
0
0
0
0
Figure 13-4. Core Watchdog Control Register (CWCR)
Table 13-5. CWCR Field Description
Field
Description
7
CWE
Core watchdog enable.
0 SWT disabled.
1 SWT enabled.
6
CWRI
Core watchdog interrupt select.
0 If a time-out occurs, the CWT generates an interrupt to the processor core. The interrupt level for the CWT is
programmed in the interrupt control register 8 (ICR8) of INTC0.
1 Reserved. If a one is written, undetermined behavior results.
Note: If a core reset is required, the watchdog interrupt should set the soft reset bit in the interrupt controller.
5–3
CWT[2:0]
Core watchdog timing delay. These bits select the timeout period for the CWT as shown in the following table. At
system reset, the CWT field is cleared signaling the minimum time-out period but the watchdog is disabled
(CWCR[CWE] = 0). the following table shows the core watchdog timer delay.
2
CWTA
Core watchdog transfer acknowledge enable.
0 CWTA Transfer acknowledge disabled.
1 CWTA Transfer Acknowledge enabled. After one CWT time-out period of the unacknowledged assertion of the
CWT interrupt, the transfer acknowledge asserts, which allows CWT to terminate a bus cycle and allow the
interrupt acknowledge to occur.
1
CWTAVA
L
Core watchdog transfer acknowledge valid.
0 CWTA Transfer Acknowledge has not occurred.
1 CWTA Transfer Acknowledge has occurred. Write a 1 to clear this flag bit.
0
CWTIF
Core watchdog timer interrupt flag.
0 CWT interrupt has not occurred
1 CWT interrupt has occurred. Write a 1 to clear the interrupt request.
CWT [2:0]
CWT Time-Out Period
000
2
9
Bus clock frequency
001
2
11
Bus clock frequency
010
2
13
Bus clock frequency
011
2
15
Bus clock frequency
100
2
19
Bus clock frequency
101
2
23
Bus clock frequency
110
2
27
Bus clock frequency
111
2
31
Bus clock frequency
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International
Trade
Commission,
BGA-packaged
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prior
to
September
2010:MCF52234CVM60,
MCF52235CVM60