4 functional description, 1 low-power modes, Functional description -10 – Freescale Semiconductor ColdFire MCF52210 User Manual

Page 138: Low-power modes -10

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Power Management

MCF52211 ColdFire® Integrated Microcontroller Reference Manual, Rev. 2

8-10

Freescale Semiconductor

the cycle with an error termination. At reset, the IPSBMT is enabled with a maximum timeout value. See

Figure 8-7

and

Table 8-9

for the IPSBMT definition.

8.4

Functional Description

The functions and characteristics of the low-power modes, and how each module is affected by, or affects
these modes are discussed in this section.

8.4.1

Low-Power Modes

The system enters a low-power mode by executing a STOP instruction. Which mode the device actually
enters (stop, wait, or doze) depends on what is programmed in LPCR[LPMD]. Entry into any of these
modes idles the CPU with no cycles active, powers down the system and stops all internal clocks
appropriately. During stop mode, the system clock is stopped low.

For entry into stop mode, the LPICR[ENBSTOP] bit must be set before a STOP instruction is issued.

IPSBAR

Offset: 0x0023 (IPSBMT)

Access: read/write

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

R

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

R

0

0

0

0

0

0

0

0

0

0

0

0

BME

BMT

W

Reset

0

0

0

0

0

0

0

0

0

0

0

0

1

0

0

0

Figure 8-7. IPS Bus Timeout Monitor (IPSBMT) Register

Table 8-9. IPSBMT Field Description

Field

Description

15–4

Reserved, should be cleared.

3

BME

Bus Timeout Monitor Enable
0 The bus timeout monitor is disabled.
1 The bus timeout monitor is enabled.

2–0

BMT[2:0]

Bus Monitor Timeout. This field selects the timeout period (measured in system bus clock cycles) for the bus
monitor.
000 1024 cycles
001 512 cycles
010 256 cycles
011 128 cycles
100 64 cycles
101 32 cycles
110 16 cycles
111 8 cycles

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