USB3300 SMSC Corporation, USB3300 Datasheet - Page 30

• Manufacturer Part Number: USB3300
• Description: Hi-Speed USB Host
• Manufacturer: SMSC Corporation

Revision 1.06 (07-19-06)
6.1.5.2
6.1.6
DATA[7:0]
ULPI Register Read
A ULPI register read operation is given in
= 11h for a register read. DATA[5:0] of the ULPI TXD command bye contain the register address.
At T0, the Link will place the TXD CMD on the databus. At T2, the PHY will bring NXT high, signaling
that the Link it is ready to accept the data transfer. At T3, the PHY reads the TXD CMD, determines
it is a register read, and asserts DIR to gain control of the bus. The PHY will also de-assert NXT. At
T4, the bus ownership has transferred back to the PHY and the PHY drives the requested register
onto the databus. At T5, the Link will read the databus and the PHY will drop DIR low returning control
of the bus back to the Link. After the turn around cycle, the Link must drive a ULPI Idle command at T6.
ULPI RXD CMD
The Link needs several more important states of information which were provided by the linestate[1:0],
rxactive, rxvalid and rxerror. When an implementing the OTG functions the Vbus and ID pin states
must also be transferred into the Link.
ULPI defines a Receive Command Byte (RXD CMD) that contains this information. The Encoding of
the RXD CMD byte is given in the
Transfer of the RXD CMD byte occurs when in Synchronous Mode when the PHY has control of the
bus. Transfers of the RXD CMD occur after: a transmit cmd has issued STP, a linestate change when
not transmitting, a USB receive, or an interrupt event occurs.
In
change occurs the RXD CMD is sent immediately if the DIR output is low.
When a USB Receive is occurring RXD CMDs are sent when ever NXT = 0 and DIR = 1. When a
USB Transmit occurs the RXD CMDs are returned to the Link after the STP is asserted ending the
Link to USB3300 transfer of the bytes to be sent on the transmit.
To summarize a RXD CMD transfer occurs:
NXT
CLK
STP
Figure
DIR
when DIR is low and a linestate change occurs.
when Vbus and/or ID comparators change state.
6.2, the ULPI Protocol Block determines when to send an RXD CMD. When a linestate
Idle
T0
Figure 6.5 ULPI Register Read
Txd Cmd Reg
T1
Read
DATASHEET
Table
Hi-Speed USB Host, Device or OTG PHY with ULPI Low Pin Interface
6.5.
T2
Figure
30
6.5. The Link drives a TXD CMD byte with DATA[7:6]
T3
Turn around
T4
Reg Data
T5
Turn around
T6
Idle
SMSC USB3300
Datasheet