BlueNRG-1 STEVAL-IDB007V1 - Virtual COM doesn't work, STM32L151CB stays in DFU mode

[John Smith]

STEVAL-IDB007V1- Virtual COM

I have reprogrammed the STM32L151CB on board with the following two file:

C:\Program Files (x86)\STMicroelectronics\BlueNRG GUI 3.1.0\Firmware\STM32L1_prebuilt_images\DFU_Bootloader.hex
C:\Program Files (x86)\STMicroelectronics\BlueNRG GUI 3.1.0\Firmware\STM32L1_prebuilt_images\BlueNRG_VCOM_1_8.hex

Also tried to program this files:

C:\Program Files (x86)\STMicroelectronics\BlueNRG-1_2 DK 3.1.0\Firmware\USB_to_SERIAL\DFU_Bootloader.hex
C:\Program Files (x86)\STMicroelectronics\BlueNRG-1_2 DK 3.1.0\Firmware\USB_to_SERIAL\USB_to_SERIAL.hex

But in both cases result stays the same.

I used J-link with J-flash Lite from Segger and CN6 JTAG connector on board.

The two programming step from 0x0800'0000 for the bootloader and from and 0x0800'3000 for the VCOM_1_8 are OK (program&verify).

But the VCOM doesn't appear and STM32 DFU stays in Device Manager. DL2 led is always in blinking state.

What can I do to restore my dev board?

Similar problem with no answer: https://community.st.com/s/question/0D50X00009XkYMi/bluenrg1-in-stevalidb007v1-virtual-com-ko

[Winfred LU]

Did VCOM of the board work before STM32L is reprogrammed?

Not having a J-link to test, but I tested with a ST-Link. Both ways shall work.

Just a question, is the HW modified?

[John Smith]

Finally found answer to my own question

For flashing and experiments with BlueNRG-1 chip I used st-link programmer and connected it to CN7 j-tag connector. Then I did not disconnect st-link from board I only unplugged st-link from USB. RESETN signal on CN7 connector connected to BlueNRG-1 reset pin and to Reset button on the board. When no power supplied to programmer it pulls down RESETN signal. STM32L151CBU6 MCU start normally and detect low level on RESETN and switched to DFU mode (expected behaviour on low RESETN).

STEVAL-IDB007V1M Schematic diagram