Datasheet

 2014-2016 Microchip Technology Inc. DS00001792E-page 33
USB3320
6.0 ULPI OPERATION
6.1 Overview
The USB3320 uses the industry standard ULPI digital interface to facilitate communication between the USB Trans-
ceiver (PHY) and Link (device controller). The ULPI interface is designed to reduce the number of pins required to con-
nect a discrete USB Transceiver to an ASIC or digital controller. For example, a full UTMI+ Level 3 OTG interface
requires 54 signals while a ULPI interface requires only 12 signals.
The ULPI interface is documented completely in the “UTMI+ Low Pin Interface (ULPI) Specification Revision 1.1”. The
following sections describe the operating modes of the USB3320 digital interface.
Figure 6-1 illustrates the block diagram of the ULPI digital functions. It should be noted that this USB3320 does not use
a “ULPI wrapper” around a UTMI+ PHY core as the ULPI specification implies.
The advantage of a “wrapper less” architecture is that the USB3320 has a lower USB latency than a design which must
first register signals into the PHY’s wrapper before the transfer to the PHY core. A low latency PHY allows a Link to use
a wrapper around a UTMI Link and still make the required USB turn-around timing given in the USB 2.0 specification.
FIGURE 6-1: ULPI DIGITAL BLOCK DIAGRAM
NOTE:
The ULPI interface
is a wrapperless
design.
POR
ULPI Register Array
Interrupt Control
6pinSerial Mode XcvrSelect[1:0] TermSelect OpMode[1:0] Reset SuspendM 3pinSerial Mode ClockSuspendM AutoResume DischrgVbus ChrgVbus IdGndDrv SpkLeftEn SpkRightEn/MicEn DpPulldown DmPulldown SwapDP/DM CarkitMode RegOutput[1:0] ChargerPullupEnDP ChargerPullupEnDM TxdEn RxdEn Indicator Complement Indicator Pass Thru UseExternal Vbus Indicator IdPullUp
Linestates[1:0]
HostDisconnect
Interface Protect Disable
VbusValid
SessionValid
SessionEnd
IdGnd
IdFloat
RidCon...Start
RidValue[2:0]
RidCon...Done
Data[7:0]
High Speed TX
Full Speed TX
Low Speed TX
High Speed Data
Recovery
Full / Low Speed
Data Recovery
ULPI Protocol
Block
HS Tx Data
FS/LS Tx Data
HS RX Data
FS/LS Data
DIR
NXT
STP
Tx Data
Rx Data
USB Transmit and Receive Logic
ULPI Register Access
RESETB
ULPI Interupt
Rid State
Machine
To RX
Analog
To TX
Analog
Transceiver Control
To
OTG
Analog
To USB
Audio
Analog