Low-Power Mode Operation

19.3 Low-Power Mode Operation

This subsection describes the operation of the PIT modules in low-power modes and halted mode of operation. Low-power modes are described in the Power Management Module. Table 19-1shows the PIT module operation in low-power modes, and how it can exit from each mode.

NOTE

The low-power interrupt control register (LPICR) in the System Control Module specifies the interrupt level at or above which the device can be brought out of a low-power mode.

Table 19-1. PIT Module Operation in Low-power Modes

Low-power Mode

PIT Operation

 

 

 

 

Mode Exit

 

 

 

 

 

 

Wait

Normal if PCR[WAIT] cleared,

Any

 

 

Interrupt at or above level in LPICR

IRQx

 

stopped otherwise

 

 

 

 

 

 

 

 

 

 

 

Doze

Normal if PCR[DOZE] cleared,

Any

 

 

Interrupt at or above level in LPICR

IRQx

 

stopped otherwise

 

 

 

 

 

 

 

 

Stop

Stopped

No

 

 

 

 

 

Halted

Normal if PCR[HALTED] cleared,

No. Any

 

 

Interrupt will be serviced upon normal

IRQx

 

stopped otherwise

exit from halted mode

 

 

 

 

 

 

 

In wait mode, the PIT module continues to operate as in run mode and can be configured to exit the low-power mode by generating an interrupt request. In doze mode with the PCSR[DOZE] bit set, PIT module operation stops. In doze mode with the PCSR[DOZE] bit cleared, doze mode does not affect PIT operation. When doze mode is exited, the PIT continues to operate in the state it was in prior to doze mode. In stop mode, the system clock is absent, and PIT module operation stops.

In halted mode with the PCSR[HALTED] bit set, PIT module operation stops. In halted mode with the PCSR[HALTED] bit cleared, halted mode does not affect PIT operation. When halted mode is exited, the PIT continues to operate in its pre-halted mode state, but any updates made in halted mode remain.

19.4 Signals

The PIT module has no off-chip signals.

19-2

MCF5282 User’s Manual

MOTOROLA

Page 416
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Motorola MCF5282, MCF5281 user manual PIT module has no off-chip signals, PIT Module Operation in Low-power Modes