Using uDMA to send data to USB ('IN')

Hello John,

There are not any example in TivaWare for DMA enabled USB. However the forum threads would be useful

e2e.ti.com/.../468467
e2e.ti.com/.../1154618

Regards
Amit

Thanks Amit. The links were useful.

Well, back to the project - but I wasn't able to get uDMA working with the USB. I tried do follow as closely as possible the information in the driverlib and the USB lib references, but no luck... I hope someone can point out where the problem is.

Here's the code I use to initialize uDMA, using ping-pong, with an IN endpoint (1):

    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_USB0);

    // Enable the GPIO peripheral used for USB, and configure the USB
    // pins.
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);
    ROM_GPIOPinTypeUSBAnalog(GPIO_PORTD_BASE, GPIO_PIN_4 | GPIO_PIN_5);


    // Initialize the transmit and receive buffers.
	USBBufferInit((tUSBBuffer *)&TxBuffer);
	USBBufferInit((tUSBBuffer *)&RxBuffer);
	USBBufferInfoGet(&TxBuffer, &TxRing);

	USBStackModeSet(0, USB_MODE_FORCE_DEVICE, 0);

	// Pass our device information to the USB library and place the device
	// on the bus.
	USBDBulkInit(0, &BulkDevice);

	// Configure Endpoint 1.
	USBDevEndpointConfigSet(USB0_BASE, USB_EP_1, 64,
							DISABLE_NAK_LIMIT |
							USB_EP_MODE_BULK |
							USB_EP_DMA_MODE_0 |
							USB_EP_AUTO_SET |
							USB_EP_DEV_IN);

	// Configure FIFO as a device IN endpoint FIFO starting at address 64
	// and is 64 bytes in size.
	USBFIFOConfigSet(USB0_BASE, USB_EP_1, 64, USB_FIFO_SZ_64, USB_EP_DEV_IN);

	ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UDMA);
	ROM_uDMAEnable();

	ROM_uDMAChannelAttributeDisable(UDMA_CHANNEL_USBEP1TX,
	                                UDMA_ATTR_ALTSELECT |
									UDMA_ATTR_USEBURST |
	                                UDMA_ATTR_HIGH_PRIORITY |
	                                UDMA_ATTR_REQMASK);

	ROM_uDMAChannelControlSet(UDMA_CHANNEL_USBEP1TX | UDMA_PRI_SELECT,
	                          UDMA_SIZE_32 |
							  UDMA_SRC_INC_32 |
							  UDMA_DST_INC_NONE |
	                          UDMA_ARB_256);

	ROM_uDMAChannelControlSet(UDMA_CHANNEL_USBEP1TX | UDMA_ALT_SELECT,
	                          UDMA_SIZE_32 |
							  UDMA_SRC_INC_32 |
							  UDMA_DST_INC_NONE |
	                          UDMA_ARB_256);

	ROM_uDMAChannelTransferSet(UDMA_CHANNEL_USBEP1TX | UDMA_PRI_SELECT,
	                           UDMA_MODE_PINGPONG,
	                           TxData_A,
							   (void *)ROM_USBFIFOAddrGet(USB0_BASE, USB_EP_1),
							   sizeof(TxData_A));

	ROM_uDMAChannelTransferSet(UDMA_CHANNEL_USBEP1TX | UDMA_ALT_SELECT,
	                           UDMA_MODE_PINGPONG,
							   TxData_B,
							   (void *)ROM_USBFIFOAddrGet(USB0_BASE, USB_EP_1),
							   sizeof(TxData_B));

	// Enable uDMA burst mode.
	ROM_uDMAChannelAttributeEnable(UDMA_CHANNEL_USBEP1TX,
								   UDMA_ATTR_USEBURST);

}

Later, in the main program. I enable:

    ROM_IntEnable(INT_USB0);

    ROM_uDMAChannelEnable(UDMA_CHANNEL_USBEP1TX);

The device enumerates correctly, but data is never sent. The TxHandler interrupt USB_EVENT_TX_COMPLETE is never called either.

Am I forgetting something?

Hello John

A CCS project zip and attached to the forum post would be more useful resource then code snippets!!!

Regards
Amit

My apologies for the delay. We had serious (and very strange) problems with a server yesterday.

I've made a copy of the project, and removed most of the code I had already disabled (I hope).

Notes:

-The buffer I prepare to send does not contain initialized data - it was only for testing.

-I know I should re-start when the end of transmission interrupt appears - but the interrupt is never generated.

I hope this is the correct way to insert a file...

usb_dev_bulk_copy.tar.gz

Hello John

I believe, you have tested the scaled down version, to be not working with the same symptoms are earlier?

Regards
Amit

Correct - the USB interface is recognized (i.e. the host can connect and claim the USB interface), but the bulk transfer does not work. In the Launchpad, no interrupt is detected.
This might be of help: On activating the board, enumeration seems normal - Manufacturer, Product, Serialnumber. Then there's the set configuration (Ok), and description string ('Bulk data configuration', and ...Interface). A STATUS request.
At this moment, there is another descriptor request, but the board replies with a malformed packet, and all bus communication stops.

Hello John,

Thanks for the confirmation

Regards
Amit