
Power Management
Freescale Semiconductor
8-9
counter that divides the input clock by 2
n
, where
n
is the value of the programmable counter field,
CDR[LPDIV]. The programmed value of the divider may be changed without glitches or otherwise
negative affects to the system. While in this mode, the PLL is placed in bypass mode to reduce overall
system power consumption.
Limp mode may also be entered and exited from by writing to the MISCCR[LIMP] bit.
While in this mode a 3:1 ratio is maintained between the core and the primary bus clock. Because they do
not function at speeds as low as the minimum input clock frequency, the SDRAM controller, both USB
modules, and FEC are not functional in limp mode.
8.3.3
Low-Power Modes
The system enters a low-power mode by executing a STOP instruction. The low-power mode the device
actually enters (stop, wait, or doze) depends on the setting of 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.
A wake-up event is required to exit a low-power mode and return to run mode. Wake-up events consist of
any of these conditions:
•
Any type of reset
•
Any valid, enabled interrupt request
Exiting from low power mode via an interrupt request requires:
•
An interrupt request whose priority is higher than the value programmed in the WCR[PRILVL].
•
An interrupt request whose priority is 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.
8.3.3.1
Run Mode
Run mode is the normal system operating mode. Current consumption in this mode is related directly to
the system clock frequency.
8.3.3.2
Wait Mode
Wait mode is intended to be used to stop only the CPU and memory clocks until a wake-up 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.
8.3.3.3
Doze Mode
Doze mode affects the CPU in the same manner as wait mode, except that some peripherals define
individual operational characteristics in doze mode. Peripherals which continue to run and have the
MCF5329 Reference Manual, Rev 3
Содержание MCF5329
Страница 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 126: ...Enhanced Multiply Accumulate Unit EMAC 4 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 564: ...Liquid Crystal Display Controller LCDC 22 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 692: ...Programmable Interrupt Timers PIT0 PIT3 28 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 720: ...Queued Serial Peripheral Interface QSPI 30 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 790: ...Message Digest Hardware Accelerator MDHA 33 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 902: ...Register Memory Map Quick Reference A 26 Freescale Semiconductor MCF5329 Reference Manual Rev 3...