USB bulk in interrupt missing

yangdawei2 · ‎2010-06-08

Posted on June 09, 2010 at 03:59

Hi all,

I am debugging a device which connects to PC through USB cable. On PC side, this USB device has been enumerated as a serial port. It works now, I can see the new COM4 has appeared.

The problem is through the Hyperterminal, I can send many key strokes to device, but there is no data been sent back.

I am using end point1 to transmit, end point 3 to receive data. Through the JTAG, I can see the end point 1's transmission byte counter been set to 1, 1 byte data been write to PMA end point 1's transmission address, end point 1 register's STAT TX[1:0] been set to '11' which means valid. The code is:

u32 VCOM_Send(BYTE* buf, u32 len)

{

if(len > USBCOMMS_PORT_DATA_SIZE)

{

remainData = len - USBCOMMS_PORT_DATA_SIZE;

len = USBCOMMS_PORT_DATA_SIZE;

}

UserToPMABufferCopy(buf, ENDP1_TXADDR, len);

SetEPTxCount(ENDP1, len);

SetEPTxValid(ENDP1);

return 0;

}

But there is no interrupt happens after the VCOM_Send(). At the same time, the bit DTOG_TX and bit CTR TX in end point 1 register are all cleared which should be set by hardware.

The end point descriptor is:

/*Endpoint 3 Descriptor*/

0x07, /* bLength: Endpoint Descriptor size */

USB_ENDPOINT_DESCRIPTOR_TYPE, /* bDescriptorType: Endpoint */

0x03, /* bEndpointAddress: (OUT3) */

0x02, /* bmAttributes: Bulk */

USBCOMMS_PORT_DATA_SIZE, /* wMaxPacketSize: */

0x00,

0x00, /* bInterval: ignore for Bulk transfer */

/*Endpoint 1 Descriptor*/

0x07, /* bLength: Endpoint Descriptor size */

USB_ENDPOINT_DESCRIPTOR_TYPE, /* bDescriptorType: Endpoint */

0x81, /* bEndpointAddress: (IN1) */

0x02, /* bmAttributes: Bulk */

USBCOMMS_PORT_DATA_SIZE, /* wMaxPacketSize: */

0x00,

0x00 /* bInterval: ignore for Bulk transfer */

Is there any one can give any clues that I can go further to find the problem?

Thanks in advance!

Dawei

tsuneo · ‎2010-06-11

Posted on June 11, 2010 at 16:16

1) Is the bulk IN endpoint enabled and initialized in _Reset() callback?

(ST USB stack does it in bus reset handler, but better USB coding practice is doing it in Set_Configuration handler)

2) Do you have an interrupt IN endpoint on the Communications Class interface?

Also, is this endpoint is enabled / initialized ?

Even if you don't send any Serial_State notification over the interrupt IN endpoint, this endpoint is required.

Without this endpoint, Windows CDC driver (usbser.sys) stops polling on the bulk IN endpoint, too.

Tsuneo

yangdawei2 · ‎2010-06-14

Posted on June 15, 2010 at 02:42

Hi Tsuneo,

Thank you for your reply.

This problem has been fixed by some changes in the end point settings. I could not make sure what is the exact change, but it works after I reconfigured the sending and reveiving addresses of end point 0, 1 and 3.

Cheers,

Dawei