Datasheet

Highly Integrated Full Featured Hi-Speed USB 2.0 ULPI Transceiver
Datasheet
SMSC USB3320 41 Revision 1.0 (07-14-09)
DATASHEET
5.10 Reference Frequency Selection
The USB3320 is configured for the desired reference frequency by the REFSEL[2], REFSEL[1] and
REFSEL[0] pins. If a pin is connected to VDDIO, the value of “1” is assigned. Connect the pin to
ground to assign a “0.” When using the ULPI Input Clock Mode (60MHz REFCLK Mode), the reference
frequency is always fixed at 60 MHz. Eight reference clock frequencies are available as described in
Table 5.10.
Table 5.10 Configuration to Select Reference Clock Frequency
CONFIGURATION PINS DESCRIPTION
REFSEL[2] REFSEL[1] REFSEL[0] REFERENCE FREQUENCY
0 0 0 52 MHz
0 0 1 38.4 MHz
0 1 0 12 MHz
0 1 1 27 MHz
1 0 0 13 MHz
1 0 1 19.2 MHz
1 1 0 26 MHz
1 1 1 24 MHz