Project code not running when measuring power with Nucleo-LPM01A power consumption measurement board.

[TSchi.2269]

I am looking to get a good power consumption measurement of my STM32L011K4. I bought the Nucleo-LPM01A for that. However, the project I've loaded onto my L011K4 does not load when in USB mode. I've checked the user manual UM2243, but that described only how to measure the power of the MCU as use case.

What should/can I do?

[Landry]

Hi TSchi.2269 ,

When you say "the project I've loaded onto my L011K4 does not load when in USB mode" , you mean your board doesn't start ?

You have to know that powershield can only deliver 50mA max , are you sure you are under this value with your setup ?

Landry

[TSchi.2269]

Hello @Landry​ , thanks for your answer. The board itself starts, meaning the LPM01A starts. The CubeMonitor-Power finds the board on COM-port and I can connect to it. However, My L011K4 does not start. I only see a faint red LED on my L011K4. I put it on the LPM01A Nucleo32 slot, just as show in UM2243.

I developed firmware for the L011K4 with different power modes (low powered etc.) and I want to measure the Amperage of the board with my firmware. After the initialisation of the HAL-functions, I make the on-board green LED blink 2 times. The thing is, when I put the L011K4 on the LPM01A, the green LED never blinks, meaning the software is never initialised. If I power the L011K4 with USB, everything works fine, but then the LPM01A gives an error.

What is the correct way to measure the power consumption of the L011K4 (or any Nucleo32 board) with its firmware running on the LPM01A?

Thank you very much.

[Philippe Cherbonnel]

Hello @TSchi.2269​ ,

You are using board NUCLEO-L011K4, therefore with ST-Link circuitry embedded.

On this board, the STM32L0 device NRST signal is connected to push button and to ST-Link. If you supply the board directly through 3.3V-GND connectors and if ST-Link is not powered, then it forces NRST to ground, preventing STM32L0 device to boot.

You have to change configuration of the NUCLEO-L011K4 board, as mentionned in user manual UM1956: "When the board is powered by +3V3 (CN4 pin 14), the solder bridge SB14 and SB9 (NRST) must be off".

You can have a first try by removing SB9 only, this configuration should not prevent typical use case "ST-Link only" afterwards.

I would recommend to debug your setup by separating the potential issues:

1. Supply your NUCLEO-L011K4 board through 2 wires on 3.3V-GND connectors with an external power supply source (without LPM01A)
2. Add LPM01A board to the setup: replace external power supply source by LPM01A board.

Best regards

Philippe

[TSchi.2269]

@Philippe Cherbonnel​  thanks for your message.

You are indeed right. I tried it out, in another way, and yes, when I hade the L011K4 connected to an external power source, it didn't work either. Then, when I hooked it up to the LPM01A and jumpstarted the L011K4, it indeed worked. However, I now have the following question: if I remove the solder bridge SB14 and SB9, are there current functionalities that will be lost (e.g. is it possible for ST-Link to not work anymore)? I noticed these solder bridges where connected through capacitors (at least one of them at least). I'm afraid to destroy something and be unfixable.

[Philippe Cherbonnel]

​Hello,

About functionalities lost in typical use case with ST-Link (for power supply and debug):

- SB9: it connects reset signal to target MCU. You should not lose functionalities for typical debug, except maybe in some cases (debugger wake-up from target low power mode, ...) but can you can use physical reset push button to reset your application.

- SB14: it connects LDO supplying ST-Link circuitry to the target MCU (STM32L0 on your board). If you remove it, you will have to supply the target MCU separately.

You can have a first try by removing SB9 only and supplying the STM32L0 at 3.3V (same output voltage as LDO output), thus keeping the board usable with typical use case "ST-Link only".

Best regards

Philippe

[TSchi.2269]

This reply indeed worked. I looked at it with a circuit expert (I'm just a simple software dev myself). We desoldered only the SB9, and connected power to one of the Jumper pins on the jumber on the bottom of the board. This worked!

Thanks :)