Highly Integrated Full Featured Hi-Speed USB 2.0 ULPI Transceiver
Datasheet
it may be desirable to compensate for loss by adjusting the HS transmitter amplitude. The Boost bits
in the HS TX Boost register may be configured to adjust the HS transmitter amplitude at the DP and
DM pins.
5.2.2
Termination Resistors
The USB3320 transceiver fully integrates all of the USB termination resistors on both DP and DM. This
includes 1.5kΩ pull-up resistors, 15kΩ pull-down resistors and the 45Ω high speed termination
resistors. These resistors require no tuning or trimming by the Link. The state of the resistors is
determined by the operating mode of the transceiver when operating in synchronous mode.
The XcvrSelect[1:0], TermSelect and OpMode[1:0] bits in the Function Control register, and the
DpPulldown and DmPulldown bits in the OTG Control register control the configuration. The possible
valid resistor combinations are shown in Table 5.1, and operation is guaranteed in only the
configurations shown. If a ULPI Register Setting is configured that does not match a setting in the
table, the transceiver operation is not guaranteed and the settings in the last row of Table 5.1 will be
used.
RPU_DP_EN activates the 1.5kΩ DP pull-up resistor
RPU_DM_EN activates the 1.5kΩ DM pull-up resistor
RPD_DP_EN activates the 15kΩ DP pull-down resistor
RPD_DM_EN activates the 15kΩ DM pull-down resistor
HSTERM_EN activates the 45Ω DP and DM high speed termination resistors
The USB3320 also includes two DP and DM pull-up resistors described in Section 5.8.
Table 5.1 DP/DM Termination vs. Signaling Mode
USB3320 TERMINATION
RESISTOR SETTINGS
ULPI REGISTER SETTINGS
SIGNALING MODE
General Settings
Tri-State Drivers
XXb
01b
Xb
0b
01b
00b
Xb
1b
Xb
1b
0b
0b
0b
0b
0b
1b
0b
1b
0b
0b
Power-up or VBUS < VSESSEND
Host Settings
Host Chirp
00b
00b
X1b
01b
01b
10b
10b
0b
0b
1b
1b
1b
1b
1b
10b
00b
00b
00b
10b
00b
00b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
0b
0b
0b
0b
0b
0b
0b
0b
0b
0b
0b
0b
0b
0b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
0b
0b
0b
0b
0b
Host Hi-Speed
Host Full Speed
Host HS/FS Suspend
Host HS/FS Resume
Host low Speed
Host LS Suspend
Revision 1.0 (07-14-09)
SMSC USB3320
DATA2S4HEET
SMSC [ SMSC CORPORATION ]
