STM32F373 USB boot with 24MHz oscillator not crystal on HSE

[area.1]

I have 4 x STM32F373CCT6 on a custom board connected to a USB hub, all of which are clocked from a 3v3 24MHz oscillator ( rather than putting down 5 crystals and all the caps ). I have the 1k5 resistor pull up on the D+ line. when the board is powered up ( from the PC USB connection to the hub ) all 4 devices show as invalid descriptors when they enumerate

if i do a basic cube project setup with 24MHz bypass on the HSE and all the relevant clock setup, a CDC port enumerates fine when the device is programmed by either the UART or SWD connection so I know that the USB lines aren't the wrong way up , the clocks can be right inernally etc so fundamentally all can be ok but the DFU boot isn't

can someone point out the deliberate mistake?

thanks

Andy

[waclawek.jan]

Try what the bootloader probably does: enable HSE without enabling HSEBYP, and wait until HSERDY.

JW

[waclawek.jan]

Hi @area.1​ ,

have you ever resolved this issue?

Thanks,

JW

[area.1]

If I remember correctly, the fundamental(ly!) stupid issue is the boot loader can only run from a crystal not the bypass oscillator.

Given I had a connection to the UART as well, I just used that to drive the boot loader instead as I could also control boo0 and reset

[waclawek.jan]

Thanks for your reply.

JW