RTOS/MSP-EXP430FR5994: Recommendations for low power operation

Hello,

I want to use RTOS for development the software components of my project.

I use the cfg file of my project with the purpose of configuring the low power consumption. Opening the power module, checking "Idle CPU" and choosing LPM3 or LPM4.

I am measuring with the multimeter the standby current connecting the GND jumper and the instrument between the 3V3 line.

I measured similar values in both LPM3 and LPM4 of 337 uA. I have the uSD inserted and removed it the new current is of 260 uA.

Is it possible to achieve less power consumption?

Sounds estrange that the current is the same with both power modes...any idea??

If possible with RTOS, I would like to achieve a low-power consumption.

My project is very simple:

I configure the board, the ADC and the RTC with the corresponding alarma in the main function a before calling bios_start.

The alarm fires and Hwi associated with the RTC is executed.

A Swi, which configures the RTC alarma again and start the conversion of the ADC is posted.

When the ADC value is available the corresponding Hwi, which stores the value in a variable and post a semaphore, is executed.

Finally the task with saves the data in the uSD is executed. At the end, the semaphore is pending again.

My Idle module is configured as shown:

Thanks and regards,

Juan Antonio

Hello,

I have measured the energy following several ways: with Energy Trace in both debug and no debug mode and with a external multimeter.

Moreover, Energy Trace++ was not set by default and after activating this tool I have tested several things.

I have observed that adding the fatfs module to the .cfg file the micro controller is working about 5-6 % in active mode and the rest in LPM3. However, removing the fatfs module the active mode percentage is reduced below 1 %.

I need to use the uSD card in my project. Is it possible to use the fatfs module dynamically and avoiding this extra power consumption?

Thanks and regards,

Juan Antonio

The fatfs library is a third party library. Please allow me some time to ask around and see what I can find that can help you.

-Nima

Are you using FatFs Raw example/approach or the FatFs with the fopen and fread, fwrite, etc.?

Could you try to use f_open, and other raw access functions? I would like to see if that lowers your power consumption.

Hello Nima,

Excuse me. I was finishing other sections of the project.

I believe that the problem is solved. I explain the tests carried out:

1.- Testing the original fatsdraw project for MSP430FR5994 the device is only working in active mode.

2.- I copy and paste the previous project and configuring low power mode and removing "idle" component in the .cfg file, these are the results:

The active mode is about 6% (bad number for power consumption). The device is switching many times between LPM3 and AM.

I tried to remove the fatfs component, but some error appear when building the project.

3.- The original fated project provides similar results as fatsdraw project. Later, I copy and paste this project with another name, I removed the idle and the fatfs componentes and I configured the low power mode as above. These are the results for these conditions:

I like too much these results: the active mode is below 1%, there are little changes between AM and LPM3 and the project is working.

Then, what is the advantage of using fatfs module in the .cfg file?

Thanks and regards,

Juan Antonio

If you removed the FatFS module from the .cfg, how is your project accessing the SD card?

Hello Nima,

The project is attached. You can see that the fatfs and the idle module have been removed and the project can use the uSD without any error.

Regards,

Juan Antoniofatsd_kk.zip