Motorola MCF5282, MCF5281 user manual Run Mode, Wait Mode, Doze Mode, Stop Mode

Models: MCF5282 MCF5281

1 816
Download 816 pages 28.97 Kb
Page 174
Image 174

Functional Description

The latter method of exiting from low-power mode, by a valid and enabled interrupt request, requires several things:

An interrupt request whose priority is higher than the value programmed in the XLPM_IPL field of the LPICR

An interrupt request whose priority higher than the value programmed in the interrupt priority mask (I) field of the core’s status register

An interrupt request from a source which is not masked in the interrupt controller’s interrupt mask register

An interrupt request which has been enabled at the module of the interrupt’s origin

7.3.1.1Run Mode

Run mode is the normal system operating mode. Current consumption in this mode is related directly to the system clock frequency.

7.3.1.2Wait Mode

Wait mode is intended to be used to stop only the CPU and memory clocks until a wakeup event is detected. In this mode, peripherals may be programmed to continue operating and can generate interrupts, which cause the CPU to exit from wait mode.

7.3.1.3Doze Mode

Doze mode affects the CPU in the same manner as wait mode, except that each peripheral defines individual operational characteristics in doze mode. Peripherals which continue to run and have the capability of producing interrupts may cause the CPU to exit the doze mode and return to run mode. Peripherals which are stopped will restart operation on exit from doze mode as defined for each peripheral.

7.3.1.4Stop Mode

Stop mode affects the CPU in the same manner as the wait and doze modes, except that all clocks to the system are stopped and the peripherals cease operation.

Stop mode must be entered in a controlled manner to ensure that any current operation is properly terminated. When exiting stop mode, most peripherals retain their pre-stop status and resume operation.

The following subsections specify the operation of each module while in and when exiting low-power modes.

7-6

MCF5282 User’s Manual

MOTOROLA

Page 174
Image 174
Motorola MCF5282, MCF5281 user manual Run Mode, Wait Mode, Doze Mode, Stop Mode