STM32F746G-Discovery, USB-HS MSC example, after power-off and on, the firmware doesn't work.

taz1000 · ‎2016-07-04

Posted on July 04, 2016 at 09:21

Test Environment

STM32F746G-Discovery

MDK-ARM, uvision V5.14.0.0 (Licenced)

USB High-Speed, Mass Storage Class Example

( ST_STM32F\STM32Cube7\STM32Cube_FW_F7_V1.4.0\Projects\STM32746G-Discovery\Applications\USB_Device\MSC_Standalone\MDK-ARM )

1. Compilation works okay with MDK-ARM.

2. Board is powered by 5V_LINK (CN14) and USB-HS is connected via CN12.

2. Pressing 'Download' button works okay.

2-1. PC recognizes 'removable disc'

3. Test I.

3-1. dis-connect USB-HS (CN12) : 'removable disc' disappears

3-2. and re-connect : PC recognizes it as 'removable disc'

3-3. pressing reset button : during pressing, 'removable disc' disappears

3-4. Releasing reset button : PC recognizes it as 'removable disc'

4. Test II.

4-1. Disconnect power (CN14)

4-2. Re-connect power : 'removable disc' is not recognized any more.

4-3. Reset button : no change.

5. I change the compile option to USE_USB_FS

5-1. Item 3 (Test I) and Item 4 (Test II) works okay.

From the tests, I suspect

- USB HS MSC example code has initialization error, so it doesn't work with power-up.

Can you test the Cube_FW_F7_V1.4.0 USB HS MSC example on your STM32F746G discovery and share the result ?

Thanks,

Best Regards,

Danny

taz1000 · ‎2016-07-04

Posted on July 05, 2016 at 03:32

FAE from Korean agent Insem helped me on this topic.

It was caused by ''external power''

To use OTG function, I should use external power.

I thought

- I only use device mode

- Right after downloading the firmware, things were okay

So I 'guess' that external power is not necessary.

But, I was wrong.

After switching to external power, the firmware works okay.

Even I power-off and on the board, the firmware works fine.