We are working on Beaglebone Black board. We will be using this as main processing unit as it is, on our custom board as final product.
As our product will be working on Battery. So, target is the main processing unit (whole beagle board) should consume around 10 to 12 mA with 5 V supply.
Where as when I put board into low power (deep sleep) using command
# echo mem > /sys/power/state
It works fine and wakes up good. But it consumes 50mA in deep sleep state. Where our target is 12mA. I am measuring current at 5V DC jack.
Presently I am using ti-sdk-am335x-evm-07.00.00.00.
I checked the linux source for making DDR into self refresh mode. But arch/arm/mach-omap2/sleep33xx.c do not have code for putting DDR into self refresh mode. Thats where I am suspecting the major power consumption is going. And I am not sure about how much PMIC would be consuming.
DO we have any exiting Linux kernel source base where, it put all peripheral into power down mode. All peripheral include DDR3, emmc, SDCARD, LAN.
Thanks and Regards
See this wiki for AM335X power consumption: http://processors.wiki.ti.com/index.php/AM335x_Power_Consumption_Summary
DDR3 cannot be powered down in DeepSleep0 mode. It is put in self-refresh though.
In reply to Biser Gatchev-XID:
I have gone through the link you provided. But it talks about processor power consumption and not about peripherals power consumption.
My requirement is over all board power consumption. I am suspecting the kernel image I got from TI sdk 7.0 donot put DDR into self refresh mode. I have concluded this by looking into kernel source.
Path : arch/arm/mach-omap2/sleep33xx.c
AS you said, it put DDR into self refresh mode. if that is the case. Board should not consume 50mA of current. As, I can see LAN is going into power down as LED goes off.And I have manually configured HDMI chipset into lowpower using i2c commands. In my setup I have not connected any monitor to the board.
May be the linux kernel source which I have, do not support it. Can you please help me pointing to git repository which support power down of all peripherals.
In reply to Ajay Kar:
The official SDK 7.0 download link is: http://software-dl.ti.com/sitara_linux/esd/AM335xSDK/latest/index_FDS.html
I am sorry, but I am using same SDK. Where I dont see code for DDR self refresh.
/* Put SDRAM in self-refresh */ ldr r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL] bic r1, r1, #EMIF_POWER_MGMT_SR_TIMER_MASK orr r1, r1, #EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES str r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL] str r1, [r0, #EMIF_POWER_MANAGEMENT_CTRL_SHDW]
ldr r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL] bic r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK orr r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE str r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
ldr r1, dram_sync_word @ a dummy access to DDR as per spec ldr r2, [r1, #0]
In reply to Steve Kipisz:
I saw this code. But believed this code makes "on chip 64KB SDRAM" into self refresh mode, but not DDR3. I will look in the code again and get back.
I went through the code base. If I check theoretical quiescent current analysis of all components then we should be able to achieve around 15mA. So, I am not sure where remaining 35mA is getting consumed.
As, of now I donot have any way to check which component is consuming how much current in low power. Can you please suggest any way I can check individual component current consumption.
And even I am not sure about how much PMIC would be consuming. I mean what PMIC would be consuming. As it remain active when we put cpu into deep sleep mode.
Do you have any power analysis report on beagle bone black for complete, not only for processor?
Do, you think that 12 to 15 mA with 5V supply will be possible to achieve.
Thanks a lot your help.
I figured it out, where the extra power is getting consumed. On Beaglebone Black, HDMI and LAN remain active even though we put system in deep sleep mode.
After removing power to HDMI and LAN, The total current board use is 18mA with 5V. So, total standby power we can achieve on Beaglebone Black board is around 0.1W
HDMI alone consume 21mA. LAN consumes 11mA.
Just thought of sharing it. Can be useful for some body.
Hi Ajay Kar
we are also working with a BBB for a scientific research program. We also would like to use the low power states of the BBB for battery driven applications. We are using latest Debian image (Linux version 3.8.13-bone67, Debian 7.6 wheezy).
Problem is, we are quite new to linux, so the question is, if it would be possible to use the mentioned Debian system to use the low power features?!
Maybe you can give some hints where to start?!
Thanks in advance
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