aboutCYpressBLE_LowPower

1.POWER MODE SUMMARY

Psoc 4 features five power modes of operations.in order of power consumption and fuctionality,they are active,sleep,deep_sleep,hibenateand stop.if you want to know some aobout typital current and wake up times for each power mode,please see table1.

 

                     Table 1. Power Mode Specs

Power
Mode

Current Range (typical)
( Vdd = 3.3 V to 5.0 V )

 

                Wakeup Time

PSoC 4200

PSoC 4200M

PSoC 4200L

Active

1.3 mA to 14 mA

–

–

–

Sleep

1.0 mA to 3 mA

0

0

0

Deep-sleep

1.3 µA to 15 µA

25 µs

25 µs

25 µs

Hibernate

150 nA to 1 µA

2 ms

0.7 ms

0.7 ms

Stop

20 nA to 80 nA

2 ms

2 ms

1.9 ms

 

2.What are we do for entering low power mode?

 2.1 sleep mode

   All peripherals are available expect CPU.

   Enter sleep mode use API fuction :CySysPmSleep().

 2.2 deep-sleep mode

   CPU,most peripherals and MHZ clocks are disable.

   Enter deep-sleep mode use API fuction:CySysPmDeepSleep().

 2.3 hibernate mdoe

   All clocks are disable,but logical states are retained.

   Enter hibernate mode use API fuction:CySysPmHiberate().

2.4 stop mode

All clocks ,CPU and all peripherals are halted,but logical states are not retained,GPIO states are retained or frozen.

Enter stop mode using the CySysPmStop() API function.

3.How to wake up

  3.1 sleep mode

   Exit from sleep mode occurs when an interrupt is triggered.

  3.2 deep-sleep mode

Exit from deep-sleep mode occurs when an interrupt is triggered.

3.3 hibernate

Exit from hibernate mode occurs when a pin or low-power comparator interrupt is triggered.

3.4 stop mode

Exit from stop mode occurs when the dedicated pin wakeup is triggered, the reset signal goes low, or if power is cycled. 

 

       

4. Power ReductionTechniques

  4.1 Turn Off Unused Components

   You can use some API fuction to reduce power,such us mycomponent_Stop,mycomponent_Sleep. then you can wake up them through mycomponent_Start,mycomponent_Wakeup. Mycomponent_Wakeup restores the
Component to its pre-sleep state. The mycomponent_Start() function also brings the Component back into operation, but it is reinitialized to its default state. 

  4.2 Run Component In a Low Speed

  Clocked integrated circuits consume more current as their clock rates increase. Reducing the operating frequency of PSoC 4 components can greatly reduce the current consumption. This technique can be applied to the Cortex-M0 CPU, SAR ADC, digital components, and others. 

  4.3 Reduce Suply Voltage

  Reducing the supply voltage is probably the easiest thing you can do to reduce the overall power consumption. Even
if the current stays the same, reducing the supply voltage from 5 V to 3 V reduces power consumption by 40 percent! 

    4.4 Use PSoC Device to Gate Current Paths 

   PCB may contain other components that draw power; the PSoC device can be used to control the current consumed by them.

   4.5 Use DMA to Move Data
    You can save power any time you offload a task from the CPU and either halt the CPU or let it do something else in parallel. The PSoC 4200M and PSoC 4200L devices have a DMA engine that can be used in active or sleep modes to transfer data with no CPU use. 

   4.6GPIOs
    The GPIOs can continue to drive the external circuitry when the PSoC device is in a low-power mode. This is helpful when you need to hold external logic at a fixed level, but it can lead to wasted power if the pins needlessly source or sink current. You should analyze your design and determine the best state for your GPIOs during low-power operation. If holding a digital output pin at logic 1 or 0 is best, then use the Pins Component’s _Write() API function to set it.
/* Set MyPin to ‘0’ for low power. */
MyPin_Write(0);
Configure all unused GPIOs to Analog HI-Z unless there is a specific reason to use a different drive mode. A Pins Component’s port-wide drive mode may be set using the _SetDriveMode() API function.
/* Set MyPin to Alg HI-Z for low power. */
MyPin_SetDriveMode(MyPin_DM_ALG_HIZ);
The flexibility of PSoC 4 makes it easy to manage GPIO drive modes to prevent unwanted current leakage.
In stop mode, the GPIO drive modes and data registers may be “frozen.” The pin states are automatically frozen by the PSoC Creator stop mode entry API function, CySysPmStop(). They must be “unfrozen” after a wakeup reset to allow their states to change—call the CySysPmUnfreezeIo() API function. 

  4.7 Debug interface

    PSoC 4 supports on-chip debugging. You may observe a higher current consumption than expected while in debug mode. This is normal because the programming and debug interface remains active in all low-power modes.