USB CDC Port Not Shown In Device Manager(MCU STM32F!103RET6)

[Smit Italiya]

Hello Everyone,

Right now i am facing the issue on detection USB.I am attaching snap shots of the my USB configuration.

USB port not shown after powering up the board. i am doing some basic thing like on receiving via USB in RX interrupt function of USB i set one flag that will used in main function for further process.

Help Me if anyone knows the issue, i stuck here since 2 days.

STMCubeIDE Version:- 1.13.2

MCU:- STM32F103RET6

Debugger:- Jlink(4000Khz)

USB DP:- PA12

USB DM :-PA11

Internal Power Supply used which is given to MCU and other board peripheral.

[Smit Italiya]

As you told me before to increase the size so is that same?(increasing RX and TX buffer size)?

[Smit Italiya]

as per schematic no pull up on DP pin, It is mandatory to detect USB?  

[AScha.3]

yes.  

ie.   R6 1k5

[gbm]

Yes, with F103 the pull-up resistor is mandatory.

If there is a software problem with the USB stack, you should increase the STACK and HEAP size, not the buffer size. As I already wrote, only 64 bytes of RX buffer are used, regardless of its size.

[Smit Italiya]

Thanks, gbm i increased stack and heap size to 600 but after powering up mcu if i connect usb then it shows that stm32 bootloader mode, then after  i pull down the boot pin and checks again but this time shows usb not recognized.

[Smit Italiya]

Thanks,AScha.3 i will try this and let you know the result.

[Smit Italiya]

if MCU would be L073RB8 then pull up required or not?

[gbm · Accepted solution]

If there is a need to increase stack and heap size, make them at least 1024 bytes or more. Pullup resistor is required only with F1 series. The built-in USB bootloader is not present in F103, so some of the information you provide is false or at least incomplete.

[Smit Italiya]

Thanks gbm,

Okay will increase the size and let you know but information is right when we found that in F1 series USB detection problem is common then we changed the F1 to L073RB8 to test the usb but no result on both at least pop up msg will come in L0 series but in F1 nothing happens we try on both mcu we have boards of both mcus.if you have some info then share with me more

[Smit Italiya]

despite of increasing stack and heap size still getting device descriptor request failed.