USB3300 datasheet(33/55 Pages) SMSC

33 / 55 page

Hi-Speed USB Host, Device or OTG PHY with ULPI Low Pin Interface

Datasheet

SMSC USB3300

Revision 1.08 (11-07-07)

DATASHEET

During transmit the PHY will use NXT to control the rate of data flow into the PHY. If the USB3300

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 that the Link cannot assert STP with NXT de-asserted since the USB3300 is

expecting to fetch another byte from the Link in this state).

Once, the USB3300 completes transmitting, the DP/DM lines return to idle and an RXD CMD is

returned to the Link so the inter-packet timers may be updated by linestate.

In the case of Full Speed or Low Speed, once STP is asserted each FS/LS bit transition will generate

a RXD CMD since the bit times are relatively slow.

6.1.8

USB3300 Receiver

The USB3300 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 RXD CMD transfers.

Figure 6.7, "ULPI Receive" shows a basic USB packet received by the USB3300 over the ULPI

interface.

Figure 6.6 ULPI Transmit

DATA[7:0]

DP/DM

DIR

CLK

STP

NXT

TXDCMD

(USBtx)

Idle

IDLE

SE0

!SQUELCH

SE0

Turn

Around

Turn

Around

RXD

CMD

USB3300 датащи(PDF) 33 Page - SMSC Corporation