Why can't i note use stm32L011 nucleo board when it is powered by an USB charger instead a PC USB

[Serge Lopez_2]

I want use to use a stm32L011 nucleo borad without a PC. Once the code is downloaded I want just supply the power of the nucleo board through the USB port with a single USB charger.

When I did it, the nucleo board doesn't start the code.

If I supply the nucleo borad through the USB port with a PC USB, the code works.

Why ?

And how to solve it?

Thanks in advance for your answers

BR

Serge Lopze

[Tesla DeLorean]

Update the ST-LINK firmware, you probably have version 25 or there about.

Use ST-LINK Utilities, Cube Programmer or standalone update app.​

[Serge Lopez_2]

Hi Clive,

I found the solution to this. The solution documented on the ST's document : UM1956 - User manusl STm32 Nucleo borad page 16 ,§ 6.4.1 the note at the bottom of the page. (DocID028406 Rev3-

"In case the board is powered by a USB charger, there is no USB enumeration, so the LED

LD2 remains set to off permanently and the target STM32 is not powered. In this specific

case the SB1 must be set to on, to allow the target STM32 to be powered anyway.

"

I apologize to you for the distrub. At the end I learnt : I should be less layz and read better the specs that iI did until now.

Thanks for your answer

Have a nice week end.

Serge

[Tesla DeLorean]

No problem. The old ST-LINK firmware had a habit of clamping the NRST pin low when not talking to a PC.