Can't flash anything on STM32L07

[Alexandre Poincet]

Posted on June 08, 2018 at 05:21

Hi,

I'm actually working with a LoRaWAN kit (

https://techship.com/products/acsip-lorawan-evk-antenna-kit-s76sxb/

) based on STM32L073x and Semtech SX1276 radio module.So the kit comes with examples based on Semtech example. I have been able to flash thoses examples via SWD pins and an STM32F0 Discovery ST-Link.But since yesterday, I can't flash anything on the kit. I'm using Keil uVision5. When I try to flash something I get the error message 'No target connected'. I can't even connect with the ST-Link Utility and when I try to set Boot0 High and use STM32 Flash Loader the program crash right after selecting the COM port when I need to select the device in the target list.

ST-Link is not the problem as I can still flash on the Discovery board.

I'm really out of idea, I don't know if the MCU is bricked or anything else.

If you have any idea, please tell me beacause I'm totaly stuck at the moment.

Thanks

EDIT : Last time I was able to flash, I tried to change the LoRaWAN region (transmission frequency from ASIA 923 to US 915). I don't remenber if the problem occured right after this change or if I was able to flash one or two more times after that.

#bootloader ##stm32l0 #lorawan

[Tesla DeLorean]

Posted on June 08, 2018 at 05:41

Can the ST-LINK connect with BOOT0 High?

Is the NRST pin available to the ST-LINK?

[Alexandre Poincet]

Posted on June 08, 2018 at 05:56

Hi

Turvey.Clive.002

and thanks for your consideration.

I'm pretty new to STM32 development, specially via SWD pins as I always used discovery boards with embedded ST-Link and this is the first time I use ST-Link for external MCU. Can you explain me how can I check what you are asking me ?

Thank you

[Tesla DeLorean]

Posted on June 08, 2018 at 06:07

Ok, so you said you tried the Flash Loader when BOOT0 is High, have you tried connecting with the ST-LINK Utilities in that condition? If it connects, erase your code from the device.

The ST-LINK should provide SWCLK, SWDIO, NRST, etc. Do you have all three connected? Can you try selecting the 'Connect Under Reset' mode for the ST-LINK?

[Alexandre Poincet]

Posted on June 08, 2018 at 06:21

Ok I understand now. Yes I tried to set BOOT0 High but ST-Link Utility can't connect to device.

And yes the SWD NRST pin is connected to target RST pin and I selected 'connect under reset' but it does not change anything.

I connected ST-Link to target like this :

GND      -->   GND

NRST    -->   RST

SWCLK -->   SWC

SWDIO  -->   SWD

[Alexandre Poincet]

Posted on June 19, 2018 at 08:20

So I finnaly succeed to flash something.

First I think there's a problem with the SWD pins, i can't flash anything using the ST-LINK.

I finnaly succed to flash something by seting BOOT0 to high and using the STM32 Flash Demonstrator. I run the program in Windows 7 compatibility and now it works.