STM32L152 VCP Speed problem

igal · ‎2014-12-09

Posted on December 09, 2014 at 11:35

Hi,

I have to usethe USB-FS of the STM32L152 as a bridge between a PC and a BLE module.

I have a PC firmware upgrade via USART for the BLE.

If I connect PC->FTDI->BLE I manage to program the BLE with no problem.

I tried to replace the FTDI with STM32L152 but the firmware upgrade application on the PC gets time out error, the response from the BLE isn't received fast enough.

The packets can be small (less than 64 bytes) later large (more than 64bytes), I have no control over this.

I use the VCP example fro ST site.

Any ideas?

Thanks

#stm32l152-usb-vcp

igal · ‎2015-02-12

Posted on February 12, 2015 at 13:14

I solved the problem

The PC app, when it receives USART (VCP) one byte after the other he looks at them as separated packets and so it gets an error. I used a timer to check I get additional USART byte in less than 2 bits duration, if I didn't the accumulated bytes are sent to the PC as one packet.