BULK IN pending(6747 usb peripheral mode)

twicave Feng

Hi,All.

I'm using c6747's USB0 in peripheral mode now. The mission target is createing a BULK link with PC(Windows XP). Bulk OUT is OK. But I got problem in Bulk IN process -- PC initiate a BULK IN req. But Dsp's ISR didn't triggered. so the communication is pending.

I checked PERI_TXCSR of EP_IN. found UNDERRUN bit is set when host send a BULK_IN req.(with no interrupt be generated.)

Here is my question.

1.MUST I put the first package into EP_IN FIFO before Host send out "IN token"?

2.Can DSP generate a interrupt when PERI_TXCSR.UNDERRUN is set?

oh, btw, windows's wdk sample code is very powerful, If you need develope a driver program for USB device. just starting from that code. very simple.

over 15 years ago

0 clam over 15 years ago

TI__Expert 8785 points

Before receiving an IN token from the host, the data needs to be loaded into the FIFO, and the PERI_TXCSR[TXPKTRDY] bit needs to be set. If the TXPKTRDY bit is not set before the IN token is received, the UNDERRUN bit will be automatically set.

For more information, please see Section 2.7.1.2.1.2 of the USB20 user guide.

--Christina