Datasheet

Hi-Speed USB Host, Device or OTG PHY with ULPI Low Pin Interface
Datasheet
Revision 1.1 (01-24-13) 40 SMSC USB3300
DATASHEET
6.1.10.1 3pin FS/LS Serial Mode
Three pin serial mode utilizes the data bus pins for the serial functions shown in Ta ble 6.7, "Pi n
Definitions in 3 pin Serial Mode".
6.1.11 Reset Pin
The reset input of the USB3300 may be asynchronously asserted and de-asserted so long as it is held
in the asserted state continuously for a duration greater than one clkout clock cycle. The reset input
may be asserted when the USB3300 clkout signal is not active (i.e. in the suspend state caused by
asserting the SuspendM bit) but reset must only be de-asserted when the USB3300 clkout signal is
active and the reset has been held asserted for a duration greater than one clkout clock cycle. No
other PHY digital input signals may change state for two clkout clock cycles after the de-assertion of
the reset signal.
6.2 Hi-Speed USB Transceiver
The SMSC Hi-Speed USB 2.0 Transceiver consists of four blocks in the lower right corner of
Figure 6.1, "Simplified USB3300 Architecture". These four blocks are labeled HS XCVR, FS/LS XCVR,
Resistors, and Bias Gen.
6.2.1 High Speed and Full Speed Transceivers
The USB3300 transceiver meets all requirements in the USB 2.0 specification.
The receivers connect directly to the USB cable. This block contains a separate differential receiver
for HS and FS mode. Depending on the mode, the selected receiver provides the serial data stream
through the multiplexer to the RX Logic block. The FS mode section of the FS/HS RX block also
consists of a single-ended receiver on each of the data lines to determine the correct FS linestate. For
HS mode support, the FS/HS RX block contains a squelch circuit to insure that noise is never
interpreted as data.
The transmitters connect directly to the USB cable. The block contains a separate differential FS and
HS transmitter which receive encoded, bit stuffed, serialized data from the TX Logic block and transmit
it onto the USB cable.
6.2.2 Termination Resistors
The USB3300 transceiver fully integrates all of the USB termination resistors. The USB3300 includes
1.5kΩ pull-up resistors on both DP and DM and a 15kΩ pull-down resistor on both DP and DM. The
45Ω high speed termination resistors are also integrated. These resistors require no tuning or trimming
Table 6.7 Pin Definitions in 3 pin Serial Mode
SIGNAL
CONNECTED
TO DIRECTION DESCRIPTION
tx_enable DATA[0] IN Active High transmit enable
data DATA[1] I/O Tx differential data on DP/DM when tx_enable is high
RX differential data from DP/DM when tx_enable is low
se0 DATA[2] I/O Tx SE0 on DP/DM when tx_enable is high
RX SE0 from DP/DM when tx_enable is low
interrupt DATA[3] OUT Asserted when any unmasked interrupt occurs. Active high