Backup Watchdog Timer (BWT) Module
MCF52110 ColdFire® Integrated Microcontroller Reference Manual, Rev. 1
7-2
Freescale Semiconductor
Preliminary
7.1.2.1
Wait Mode
The functionality of the BWT in Wait mode depends on the value of WCR[WAIT].
When WCR[WAIT]=1, the BWT stops when the device enters Wait mode. When the device leaves Wait
mode, the BWT resumes from the state it was in when it stopped.
When WCR[WAIT]=0, the BWT continues to operate normally when the device enters Wait mode.
7.1.2.2
Doze Mode
The functionality of the BWT in Doze mode depends on the value of WCR[DOZE].
When WCR[DOZE]=1, the BWT stops when the device enters Doze mode. When the device leaves Doze
mode, the BWT resumes from the state it was in when it stopped.
When WCR[DOZE]=0, the BWT continues to operate normally when the device enters Doze mode.
7.1.2.3
Stop Mode
The functionality of the BWT in Stop mode depends on the value of WCR[STOP].
When WCR[STOP]=1, the BWT stops when the device enters Stop mode. When the device leaves Stop
mode, the BWT resumes from the state it was in when it stopped.
When WCR[STOP]=0, the BWT continues to operate normally when the device enters Stop mode.
7.2
Memory Map and Register Definition
The backup watchdog timer programming model includes registers in the BWT and clock modules. The
registers used to configure the BWT are read-always/write once, and their contents are preserved during a
warm reset. Only a Power-On Reset resets these registers to their default values.
7.2.1
Memory Map
Table 7-1. BWT Memory Map
IPSBAR
Offset
1
1
Addresses not assigned to a register and undefined register bits are reserved for expansion.
Register
Width
(bits)
Access
Reset Value
Section/Page
0x14_0000
Backup Watchdog Timer Control Register (WCR)
8
R/W
2
2
WCR and WMR are read-always/write-once, and cannot be changed until the next Power-On Reset event.
0x02
0x14_0002
Backup Watchdog Timer Modulus Register (WMR)
16
R/W
0xFFFF
0x14_0004
Backup Watchdog Timer Count Register (WCNTR)
16
R
0xFFFF
0x14_0006
Backup Watchdog Timer Service Register (WSR)
16
R/W
0x00
0x12_0013
Clock Module Backup Watchdog Timer Control Register
(BWCR)
3
3
This read-always/write-once register is part of the Clock Module; see
Section 6.7.1.10, “Backup Watchdog Timer Control
,” for a detailed description.
8
R/W
0x02
