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Power consumption of Beaglebone Black sleep mode

Nick King
Expert 1280 points
Other Parts Discussed in Thread: TPS65217

Dear TI,

I am working on total power consumption by BBB

now there are various voltage to the sitara processors. by the PMIC TPS65217.pdf

VDD_CORE,VDD_MPU, VDDS_RTC,VDDS_DDR,VDDS,VDDS_SRAM_CORE_BG,VDDS_SRAM_MPU_BB,VDDS_PLL_DDR,VDDS_PLL_CORE_LCD,VDDS_PLL_MPU,VDDS_OSC,VDDA1P8V_USB0/1,VDDA3P3V_USB0/1,VDDA_ADC,VDDSHV1,VDDSHV2 *,VDDSHV3 *,VDDSHV4,VDDSHV5,VDDSHV6

Questions:

  1. may i know in sleep mode which of the above voltages are operational?
  2. i wanted to disable the LDO4 power rail during runtime now data sheet of tps65217 say to write a value of  '1' in D5  bit of the Enable Register(0x16h). it is correct or do i need to do write some other register as well or just this register(0x16h) is sufficient to turn off the LDO4 power rail. i know i2c is also connected to the LDO4 rail but for time being assume the tps65217 has i2c pull register using a different power rail. 

Regards

 

Regards

  • 0
    TI__Guru**** 393215 points
    Hi,

    1. Low power modes are described in section 8.1.4.3 of the AM335X TRM Rev. M. As you can see from Table 8-13 all power supplies are ON in all modes, except RTC-only mode.
    2. You must never try to disable only LDO4 on the BBB. This will violate the processor power requirements and probably damage the device.
  • 0 in reply to Biser Gatchev-XID
    Expert 1280 points

    Thanks Biser

    i understood the power modes of AM335X TRM rev M explained in section 8.1.4.3.

    Question:

    1)  what about the peripheral devices like LAN phy , SD-card , Nandflash(eMMC1), LCD will these devices also be put into standby/sleep mode once processor is in            sleep mode ?

    2) now once i put the device is Deepsleep0 mode now the datasheet say it can be woken up in one of the following ways.

    In section 8.1.4.5 Wakeup Sources/Events 

    GPIO0 bank
    dmtimer1_1ms (timer based wakeup)
    USB2PHY (USB resume signaling from suspend) – Both USB ports supported.
    TSC (touch screen controller, ADC monitor functions )
    UART0 (Infra-red support)
    I2C0
    RTC alarm

    now to BBB i have USB modem,LAN cable connected now once i put the device in deepsleep i want to wake up as soon as a IP packet arrives on any of the modem,wifi,ethernet interface but i see neither usb nor ethernet is connected to any gpio0 bank? or is the software already a part of the on board image that takes care of waking up device as soon as an any data arrives on USB,ethernet interface

    Regards

  • 0 in reply to Nick King
    TI__Guru**** 393215 points
    1) Not necessarily. Ethernet PHY will react to LAN activity even if it's on low-power mode. SD/eMMC have large power consumption only during R/W accesses, otherwise they consume in the range of tens of uA. LCD depends on the display itself - whether LCD and backlight power supplies are switched off.

    2) GPIO0 is just one of the wakeup sources. USB is another. Ethernet is not available as a wakeup source.
  • 0 in reply to Biser Gatchev-XID
    Expert 1280 points

    thanks biser

    Questions:

    1. so if a ethernet packet arrives on LAN while the processor is in sleep mode that packet data will never reach the host am i correct? if yes then i need to make alternate arrangements to wake up HOST.

    2. i am assuming it would be same even for USB host devices that only during USB data transfers power consumed is high else it is very low

  • 0 in reply to Nick King
    TI__Guru**** 393215 points
    1. Yes, the packet will be lost.
    2. USB Host/Device will enter low-power mode during USB Suspend, otherwise they will be active.