Issue in iMX7D Power measurement

[senthilkumarcha]

Hi, 

We are using imx7D SabreSD board with 'NXP i.MX Release Distro 4.9.11-1.0.0'. While we measured current consumption at measuring point F1(total), we got the following values.

active	freeze	standby	mem
322	323	270	310

Note: All values are in mA.

And also we measured some power domains such as VDD_SOC, VDD_ARM, VDDA_1P8, NVCC_DRAM etc.., The values are given below.

Power domains	active	freeze	standby	mem
VDD_SOC – R24	159.8	162.1	13.2	2.25
VDD_ARM – R20	5-16	11.72	7.8	0.619
VDDA_1P8 - L52	11	9	1	0.1-0.5
VDD_LPSR_IN – R32	0.0576	0.0565	0.0465	0.0472
VDD_SNVS_IN – R31	1.363	1.363	0.3207	0.1758
NVCC_DRAM – R23	46	39.64	23.19	14.97
NVCC_SD2 - R325	0.0256	7.43	0.0256	0.0256
VDDA_ADC_1P8 - L8	1.229	0.0007	0.0006	0.0006

The problem is total current consumption for mem(Deep sleep mode) and standby mode are greater than freeze state and active states while current consumption in other power domains are less in Deep sleep mode. We dont know which domains/pheripherals are consuming more current in Deep sleep and standby mode. Could anyone help us to find the domains which consumes more current in mem and standby mode.

Thanks in advance.

Regards,

Senthilkumar.C 

[senthilkumarcha]

Any updates ?

Thanks,

Senthilkumar.C

[igorpadykov]

for total board there are no power consumption figures,

customer can add power switches on power for used

board peripherals, if necessary.

Best regards
igor

[senthilkumarcha]

Hi Igor,

I have disabled all the pheripherals in device tree, still the power consumption in deep sleep mode is greater than the standby mode.

Could you please answer this ?

 The question is why the current value is increasing instead of decreasing while powering down the Fastmix/Megamix domain. Is that a bug ? or are we missing anything?

Thanks,

Senthilkumar.C

[igorpadykov]

Hi Senthilkumar

 had you followed sect.3.7. Measuring points on the SABRE platform AN5383

and sect.5.1. Steps to be performed before entering the Suspend (Deep-Sleep) mode.

It does not make sense to "disable all the pheripherals in device tree" and measure total

board power consumption. There are many other chips on board which contribute to total

power consumption and there is no way to control it. AN5383 clearly describes which

measuring points should be used.

Best regards
igor

[senthilkumarcha]

Hi,

Again we measured the total board current for low power states. This time we kept M4 core in active state. The measured values are given below.

Table 1: M4 is active

active	freeze	standby	mem
330	329	277	275

Table 2: M4 is inactive

active	freeze	standby	mem
322	323	270	310

From the table we can clearly see the difference between the current values for mem state. When M4 is active, the total board current for mem is less(more or less equal) than that of standby. But when M4 is inactive, the total board current for mem is greater than that of standby.

When we looked into linux kernel, we found that the following lines under the function imx_gpcv2_pre_suspend() in arch/arm/mach-imx/gpcv2.c

----------------------------------------------------------------------------------------------

.......

if ((!imx_src_is_m4_enabled()) ||
      (imx_src_is_m4_enabled() && imx_mu_is_m4_in_stop()))
            imx_gpcv2_mf_mix_off();;

........

---------------------------------------------------------------------------------------------------

From the code we can see that imx_gpcv2_mf_mix_off() will be called when M4 core is disabled or in STOP mode.

So calling this function increases the total current value. This is confirmed by commenting the function call and measured the current value while M4 core is inactive. The measured value is given below.

Table 3: M4 is inactive and commented imx_gpcv2_mf_mix_off() function call

active	freeze	standby	mem
322	323	270	267

The question is why the current value is increasing instead of decreasing while powering down the Fastmix/Megamix domain. Is that a bug ? or are we missing anything?

[igorpadykov]

Hi Senthilkumar

for measurement points please refer to sect.3.7. Measuring points on the SABRE platform

AN5383 i.MX 7DS Power Consumption Measurement
https://www.nxp.com/docs/en/application-note/AN5383.pdf

There is no sense to measure F1(total) as it measures total board current, including

many other chips. Please follow sect.4. Use Cases and Measurement Results and

compare results provided in tables for several power domains (VDD_ARM, VDD_SOC..)

use nsp official bsps described on

http://www.nxp.com/products/software-and-tools/software-development-tools/i.mx-software-and-tools/i....

Best regards
igor
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[senthilkumarcha]

Hi Igor,

Thanks for your response.

We measured at the same measuring points mentioned in sect.3.7. Measuring points on the SABRE platform AN5383 i.MX 7DS Power Consumption Measurement and also using the NXP official BSP.

There is no sense to measure F1(total) as it measures total board current, including many other chips.

The question is about the total board current and power consumptions of other chips only because we also confirmed that the Processor is not taking more power in low power states. We are going to use battery as power source. So we are very concerned about the total board current.
So could you please help us to find the domains/pheripherals which taking more current in Deep sleep state?

Thank you,

Senthilkumar.C