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Motorola ColdFire MCF5281 User Manual

Page 139

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Power Management

Freescale Semiconductor

7-3

NOTE

Only fixed (external) interrupt can bring a device out of stop mode. To exit
from other low-power modes, such as doze or wait, either fixed or
programmable interrupts may be used; however, the module generating the
interrupt must be enabled in that particular low-power mode.

5. Once an appropriately-high interrupt request level arrives, the interrupt controller signals its

presence, and the SIM responds by asserting the request to exit low-power mode.

6. The low-power mode control logic senses the request signal and re-enables the appropriate

clocks.

7. With the processor clocks enabled, the core processes the pending interrupt request.

7

6

4

3

0

Field ENBSTOP

XLPM_IPL

Reset

1/0

0

1/0

0

Undefined

R/W

R/W

Address

IPSBAR + 0x012

Figure 7-1. Low-Power Interrupt Control Register (LPICR)

Table 7-2. LPICR Field Descriptions

Bits

Name

Description

7

ENBSTOP

Enable low-power stop mode.
0 Low-power stop mode disabled
1 Low-power stop mode enabled. Once the core is stopped and the signal to enter stop

mode is asserted, processor clocks can be disabled.

6–4

XLPM_IPL

Exit low-power mode interrupt priority level. This field defines the interrupt priority level
needed to exit the low-power mode.Refer to

Table 7-3

.

3–0

Reserved, should be cleared.

Table 7-3. XLPM_IPL Settings

XLPM_IPL[2:0]

Interrupts Level Needed to Exit Low-Power Mode

000

Any interrupt request exits low-power mode

001

Interrupt request levels [2-7] exit low-power mode

010

Interrupt request levels [3-7] exit low-power mode

011

Interrupt request levels [4-7] exit low-power mode

100

Interrupt request levels [5-7] exit low-power mode

101

Interrupt request levels [6-7] exit low-power mode

11x

Interrupt request level [7] exits low-power mode

MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3

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