USB 1.1 Host Controller

This IP core is a cutdown USB host controller which allows communications with full-speed (12mbps) USB devices.

The IP is accessed via an AXI4-Lite slave register interface for control, status and data.

Data to be sent or received is stored in some internal FIFOs. The data is accessed through the AXI4-Lite slave port. There is no DMA engine (e.g. a bus mastering interface) associated with this IP.

The core functions well, is very small, but is fairly inefficient in terms of CPU cycles required to perform USB transfers. This core is not compliant with any standard USB host interface specification, e.g OHCI or EHCI.

Instantiation

Instance usbh_host and hookup to UTMI PHY interface and a AXI4-Lite master (e.g. from your CPU). The core requires a 48MHz/60MHz clock input, which the AXI4-Lite and UTMI interfaces are expected to be synchronous to.

Limitations

• Only tested for USB-FS (Full Speed / 12Mbit/s) only.

Testing

Verified under simulation and on FPGA with various USB devices attached (hubs, mass storage, network devices).

References

• USB 2.0 Specification
• UTMI Specification
• USB Made Simple
• UTMI to ULPI Conversion

Configuration

• USB_CLK_FREQ - Core clock frequency (supports: 60000000 or 48000000)

Size / Performance

With the default configuration...

• the design contains 317 registers, 392 LUTs (Xilinx ISE - Spartan 6)
• synthesizes to more than the required 48MHz on a Xilinx Spartan 6 LX9 (speed -3)

Register Map

Offset	Name	Description
0x00	USB_CTRL	[RW] Control of USB reset, SOF and Tx FIFO flush
0x04	USB_STATUS	[R] Line state, Rx error status and frame time
0x08	USB_IRQ_ACK	[W] Acknowledge IRQ by setting relevant bit
0x0c	USB_IRQ_STS	[R] Interrupt status
0x10	USB_IRQ_MASK	[RW] Interrupt mask
0x14	USB_XFER_DATA	[RW] Tx payload transfer length
0x18	USB_XFER_TOKEN	[RW] Transfer control info (direction, type)
0x1c	USB_RX_STAT	[R] Transfer status (Rx length, error, idle)
0x20	USB_WR_DATA	[W] Tx FIFO address for write data
0x20	USB_RD_DATA	[R] Tx FIFO address for read data

Register: USB_CTRL

Bits	Name	Description
8	TX_FLUSH	Flush Tx FIFO
7	PHY_DMPULLDOWN	UTMI PHY D+ Pulldown Enable
6	PHY_DPPULLDOWN	UTMI PHY D+ Pulldown Enable
5	PHY_TERMSELECT	UTMI PHY Termination Select
4:3	PHY_XCVRSELECT	UTMI PHY Transceiver Select
2:1	PHY_OPMODE	UTMI PHY Output Mode
0	ENABLE_SOF	Enable SOF (start of frame) packet generation

Register: USB_STATUS

Bits	Name	Description
31:16	SOF_TIME	Current frame time (0 - 48000)
2	RX_ERROR	Rx error detected (UTMI). Clear on new xfer.
1:0	LINESTATE_BITS	Line state (1 = D-, 0 = D+)

Register: USB_IRQ_ACK

Bits	Name	Description
3	DEVICE_DETECT	Interrupt on device detect (linestate != SE0).
2	ERR	Interrupt on error conditions.
1	DONE	Interrupt on transfer completion.
0	SOF	Interrupt on start of frame.

Register: USB_IRQ_STS

Bits	Name	Description
3	DEVICE_DETECT	Interrupt on device detect (linestate != SE0).
2	ERR	Interrupt on error conditions.
1	DONE	Interrupt on transfer completion.
0	SOF	Interrupt on start of frame.

Register: USB_IRQ_MASK

Bits	Name	Description
3	DEVICE_DETECT	Interrupt on device detect (linestate != SE0).
2	ERR	Interrupt on error conditions.
1	DONE	Interrupt on transfer completion.
0	SOF	Interrupt on start of frame.

Register: USB_XFER_DATA

Bits	Name	Description
15:0	TX_LEN	Tx transfer data length

Register: USB_XFER_TOKEN

Bits	Name	Description
31	START	Transfer start request
30	IN	IN transfer (1) or OUT transfer (0)
29	ACK	Send ACK in response to IN data
28	PID_DATAX	DATA1 (1) or DATA0 (0)
23:16	PID_BITS	Token PID (SETUP=0x2d, OUT=0xE1 or IN=0x69)
15:9	DEV_ADDR	Device address
8:5	EP_ADDR	Endpoint address

Register: USB_RX_STAT

Bits	Name	Description
31	START_PEND	Transfer start pending
30	CRC_ERR	CRC error detected
29	RESP_TIMEOUT	Response timeout detected (no response)
28	IDLE	SIE idle
23:16	RESP_BITS	Received response PID
15:0	COUNT_BITS	Received data count

Register: USB_WR_DATA

Bits	Name	Description
7:0	DATA	Date byte

Register: USB_RD_DATA

Bits	Name	Description
7:0	DATA	Date byte