LP-CC2652R7: Enter standby mode

Can you elaborate what SDK version and example you are testing?

I am using SDK 7.10. I used the CLI MTD example and modified for my needs. I am writing events to various queues and waiting with mq_receive for events on the queues.

I was looking more into the code. In the file PowerCC26X2.c, function Power_Init(), line 376, there is a constraint being set to disallow standby:

Looking further into this it looks like using any LF Clock Source other than External LF clock prevents the MCU from going into standby mode. Is this correct?

Is there any workaround? Because we really need the system to enter standby mode and there is no external clock source on board.

Hello Ryan

I tried measuring using EnergyTrace and the min current is about 2 mA. I have configured it as Sleepy device. Also, I am assuming that if the code enters the if(justIdle) condition, it is not entering standby mode. Is that correct? 

I am not sure what is preventing it from entering standby mode

I have also configured the following:

• BOARD_DISPLAY_USE_LCD=0
• BOARD_DISPLAY_USE_UART=0
• TIOP_CUI=0

Moreover, for me, EnergyTrace only runs when the debugger is running. I just get this window if I start EnergyTrace without starting the debugger

I have tried the steps in this thread - CCS/CCSTUDIO: EnergyTrace stand-alone-mode doesn't launch EnergyTrace window in my CCS Version: 10.0.0.00010 - Code Composer Studio forum - Code Composer Studio︎ - TI E2E support forums but nothing works.

You will need to operate EnergyTrace in standalone mode so that it is running free from the debugger.  The JTAG TMS/TCK and XDS110 backchannel UART RX/TX jumpers should also be disconnected so that they are not interfering with measurements.  Otherwise you can expect >2 ma of power consumption to be measured.  You can evaluate the gpiostandby example to confirm that you are evaluating EnergyTrace correctly.

Regards,
Ryan

Hello Ryan

I am trying with the gpiostandby example. The issue I face is this - The energytrace doesnot start if I do not start the debugger first. I guess I will post this issue on the CCS forum. Once this issue is resolved, I can better measure the currents and get back to this thread.

Thanks

You should be able to use the "EnergyTrace Technology" button from within CCS which would start the tool without entering the debugger, but you certainly can clarify this with the CCS experts.

Regards,
Ryan

Hello Ryan

I was able to run the EnergyTrace in standalone mode. The results I get are as follows:

I also ran the energytrace++ on the application. Following are the results:

And the states are as follows:

The profile shows that the CPU is in Low Power Mode almost 99.9% of the times. Yet, the minimum current is 1.9 mA. 

Could you please help me figure out how to reduce the power consumption? How do I investigate it and find out the issue? I need the CPU to be in standby mode and be consuming less than 10 uA current at that time.

Since EnergyTrace indicates that the MCU is primarily in LPM with the radio off, and no UART peripheral, it is likely that the additional power consumption is coming from the JTAG lines.  This is especially true if you are still evaluating the gpiostandby example.  You should JTAG completely disconnected when running EnergyTrace and only use the EnergyTrace+ configuration for measurement.  It is recommended that you confirm your measurements with other hardware at this point, such as a power analyzer or multimeter.

Regards,
Ryan

Hello Ryan, 

I tested this after removing the JTAG Lines. Only the 3V3 jumper is connected. 

In the gpiostandby example, the min current shows zero, which means it is probably consuming less than 1 uA current. However, when testing with the DoorLock example, the min current consumption is about 2 mA.

In the Power_init function, there is a constraint set and then, the constraint is never released. Because of this constraint, the code only enters the justIdle section shown below.

If the average current consumption of gpiostandby is zero then there is still an issue with the connection as the device is not being powered.  The 3V3, GND, and RST jumpers should be connected.

If you have not considered the TI-OpenThread Low-Power recommendations, disabled the CUI (see the Project Properties -> CCS Build -> Arm Compiler -> Predefined Symbols), and/or fail to set the SysConfig -> TI-OpenThread -> Power Management -> Power Mode of Operation to "Sleepy" then you will observe higher-than-expected power consumption.  The Power TI Driver is constrained due to the TI OpenThread application configuration.

Regards,
Ryan