USB-FS device lib Virtual COM Port problem

daviddavid942 · ‎2010-03-12

Posted on March 12, 2010 at 12:18

daviddavid942 · ‎2011-05-17

Posted on May 17, 2011 at 13:43

Hi All

after some investigation, the problem was in the Get_SerialNum function.

For some reason, the chipID is 0xFFFFFFFF on all the 3 Serial0...Serial2.

I commented out this part and edited directly the Virtual_Com_Port_StringVendor, Virtual_Com_Port_StringProduct and Virtual_Com_Port_StringSerial, giving the fixed but meaningful values.

Now the example works !

However... going back to my project.. I did the same thing but this time windows says that the USB device is not recognized.

The big difference with the given example is that after calling

Set_USBClock();

USB_Interrupts_Config();

USB_Init();

my fw starts doing many other things (the Keil RT kernel starts and task are launched).

Could this be a timing problem ?

What else ?

Thanks in advance

daviddavid942 · ‎2011-05-17

Posted on May 17, 2011 at 13:43

Hi,

one of the changes that I made to adapt the sample to my project was to increase VIRTUAL_COM_PORT_DATA_SIZE from 64 to a higher value.

Knowing nothing about USB, I also changed the last field of the DEVICE_PROP Device_Property (/*MAX PACKET SIZE*/) from 0x40 to the same higher value.

That was a mistake, apparently. After setting back this field to 0x40 the device is correctly recognized by windows.

Thanks to everybody who helped 🙂

Now the question is: is it a problem to have the VIRTUAL_COM_PORT_DATA_SIZE and usb MAX PACKET SIZE

set to differet values ?