LPM01a enumaration fails when powered from USB host port.

[deepak4code]

Hi,

I purchased new LPM01a board for power consumption analysis. When I am powering it up with usb host port (JP3 -> usb) red led light up. I tried with different hosts (desktop and laptop) but that does not works. I am getting error "Get current range command failed" in STM32CubeMonitor-Power. From google I found out that pc current limit is upto 100mA only. However, in user manual of LPM01, it specified that 500mA is required for working otherwise red led will light up. 

My first question is, if PC can be configared to deliver current upto 500mA, then how?

Alternatively, LPM01 can be also powered from external CN7 jumper with JP3 set to Ext.

In this regard, My 2nd  question is:

In Ext power mode, data acquisition with STM32CubeMonitor-Power is still possible via usb port (CN5), or only the board display is available?

[Richard.Chvr]

@PDEFO.1 any idea?

[PDEFO.1]

Hi Deepak,

All possible configuration of supplying power to the X-NUCLEO-LPM01A are described in chapter 7 of UM2243 (available on www.st.com).

In your case, you are using the default setting (chapter 7.1) by powering the LPM01A by USB. Red light on LD2 indicates that the USB enumeration between PC and LPM01A has failed. USB Port 2 & 3 are normally able to deliver sufficient current for LMP01A. 

Possible reason for enumeration failure are :

1. Faulty USB cable: The USB cable connecting the PC and the peripheral may be faulty or damaged, which can cause communication issues.

2. Driver issues: The drivers for the peripheral may not be installed or may be outdated, which can prevent the PC from recognizing the device.

3. Power issues: The peripheral may not be receiving enough power from the USB port, which can cause it to fail during enumeration.

4. Hardware issues: There may be a hardware issue with either the PC or the peripheral, such as a damaged USB port or a faulty USB controller.

5. Compatibility issues: The peripheral may not be compatible with the version of USB used by the PC, or there may be compatibility issues between the peripheral and the operating system.

From our experiency, the faulty USB cable could be investigated firstly.  Also, document UM2269 gives references to the driver that user need to install.

In chapter 7.2, 7.3 and 7.4 are described other ways to power up the LMP01A, and LCD display will normally display messages. Did you try one this configuration ?

Could you please precise which version of STM32CubeMonitor-power do you use ?

Thanks

[deepak4code]

Thanks for responding to my concern. 

I tried too many trial with cable and systems along with user manual and all. I got tired and tought of getting external powered usb hub to rid of red led if it is of power issue. Thankfully, your response arrive on time and helped me to solve the problem today. Actually the problem is with LPM01A firmware version. By default it was 1.0.1 and replaced with latest 1.0.8, and that washed away red led. simple right?

Thanks again