Highly Integrated Full Featured Hi-Speed USB 2.0 ULPI Transceiver
Datasheet
6.2.4.5
6.2.4.6
No SYNC and EOP Generation (OpMode = 11)
UTMI+ defines OpMode = 11 where no sync and EOP generation occurs in Hi-Speed operation. This
is an option to the ULPI specification and not implemented in the USB3320.
Typical USB Transmit with ULPI
Figure 6.7 shows a typical USB transmit sequence. A transmit sequence starts by the Link sending a
TXD CMD where DATA[7:6] = 01b, DATA[5:4] = 00b, and Data[3:0] = PID. The TX CMD with the PID
is followed by transmit data.
CLK
DATA[7:0]
DIR
TXD CMD
(USB tx)
Turn
Around
RXD
CMD
Turn
Around
Idle
D0
D1
D2
D3
IDLE
NXT
STP
SE0
SE0
!SQUELCH
DP/DM
Figure 6.7 ULPI Transmit in Synchronous Mode
During transmit the transceiver will use NXT to control the rate of data flow into the transceiver. If the
USB3320 pipeline is full or bit-stuffing causes the data pipeline to overfill NXT is de-asserted and the
Link will hold the value on Data until NXT is asserted. The USB Transmit ends when the Link asserts
STP while NXT is asserted.
Note: The Link cannot assert STP with NXT de-asserted since the USB3320 is expecting to fetch
another byte from the Link.
After the USB3320 completes transmitting, the DP and DM lines return to idle and a RXCMD is
returned to the Link so the inter-packet timers may be updated by linestate.
While operating in Full Speed or Low Speed, an End-of-Packet (EOP) is defined as SE0 for
approximately two bit times, followed by J for one bit time. The transceiver drives a J state for one bit
time following the SE0 to complete the EOP. The Link must wait for one bit time following line state
indication of the SE0 to J transition to allow the transceiver to complete the one bit time J state. All bit
times are relative to the speed of transmission.
In the case of Full Speed or Low Speed, after STP is asserted each FS/LS bit transition will generate
a RXCMD since the bit times are relatively slow.
6.2.5
USB Receiver
The USB3320 ULPI receiver fully supports HS, FS, and LS transmit operations. In all three modes the
receiver detects the start of packet and synchronizes to the incoming data packet. In the ULPI protocol,
a received packet has the priority and will immediately follow register reads and RXCMD transfers.
Figure 6.8 shows a basic USB packet received by the USB3320 over the ULPI interface.
SMSC USB3320
Revision 1.0 (07-14-09)
DATA5S1HEET
SMSC [ SMSC CORPORATION ]
