USB2.0 PHY IC
8.2
OPMODES
The OPMODE[1:0] pins allow control of the operating modes.
Table 8.2 Operational Modes
MODE[1:0]
STATE#
STATE NAME
DESCRIPTION
00
0
Normal Operation Transceiver operates with normal USB data encoding
and decoding
01
1
Non-Driving
Allows the transceiver logic to support a soft disconnect
feature which tri-states both the HS and FS transmitters,
and removes any termination from the USB making it
appear to an upstream port that the device has been
disconnected from the bus
10
11
2
3
Disable Bit
Stuffing and NRZI
encoding
Disables bitstuffing and NRZI encoding logic so that 1's
loaded from the TXDATA bus become 'J's on the DP/DM
and 0's become 'K's
Reserved
N/A
The OPMODE[1:0] signals are normally changed only when the transmitter and the receiver are
quiescent, i.e. when entering a test mode or for a device initiated resume.
When using OPMODE[1:0] = 10 (state 2), OPMODES are set, and then 5 60MHz clocks later,
TXVALID is asserted. In this case, the SYNC and EOP patterns are not transmitted.
The only exception to this is when OPMODE[1:0] is set to state 2 while TXVALID has been asserted
(the transceiver is transmitting a packet), in order to flag a transmission error. In this case, the PHY
has already transmitted the SYNC pattern so upon negation of TXVALID the EOP must also be
transmitted to properly terminate the packet. Changing the OPMODE[1:0] signals under all other
conditions, while the transceiver is transmitting or receiving data will generate undefined results.
Under no circumstances should the device controller change OPMODE while the DP/DM lines are still
transmitting or unpredictable changes on DP/DM are likely to occur. The same applies for
TERMSELECT and XCVRSELECT.
8.3
Test Mode Support
Table 8.3 USB2.0 Test Mode to Macrocell Mapping
GT3200, SMSC USB3250 SETUP
SIE TRANSMITTED
DATA
XCVRSELECT &
TERMSELECT
USB2.0 TEST MODES
OPERATIONAL MODE
SE0_NAK
Normal
Disable
Disable
Normal
No transmit
All '1's
HS
HS
HS
HS
J
K
All '0's
Test_Packet
Test Packet data
8.4
SE0 Handling
For FS operation, IDLE is a J state on the bus. SE0 is used as part of the EOP or to indicate reset.
When asserted in an EOP, SE0 is never asserted for more than 2 bit times. The assertion of SE0 for
more than 2.5us is interpreted as a reset by the device operating in FS mode.
SMSC GT3200, SMSC USB3250
Revision 1.3 (10-05-04)
DATA2S8HEET
SMSC [ SMSC CORPORATION ]
