Datasheet

Highly Integrated Full Featured Hi-Speed USB 2.0 ULPI Transceiver

Datasheet

SMSC USB3320 57 Revision 1.0 (07-14-09)

DATASHEET

6.4.0.2 6Pin FS/LS Serial Mode

Six pin serial mode utilizes the data bus pins for the serial functions shown in Table 6.6.

6.5 Carkit Mode

The USB3320 includes Carkit Mode to support a USB UART and USB Audio Mode.

By entering Carkit Mode, the USB3320 current drain is minimized. When operating in ULPI Input Clock

Mode (60MHz REFCLK Mode), the CLKOUT is stopped to conserve power by default. The Link may

configure the 60MHz clock to continue by setting the ClockSuspendM bit of the Interface Control

operation.

In Carkit Mode, interrupts are possible if they have been enabled in the Carkit Interrupt Enable register.

The state of each interrupt source is sampled prior to the assertion of DIR and this is compared against

the asynchronous level from interrupt source. In Carkit Mode, the Linestate signals are not available

per the ULPI specification.

Exiting Carkit Mode is the same as exiting Low Power Mode as described in Section 6.3.2. The Link

must assert STP to signal the transceiver to exit serial mode. When the transceiver can accept a

command, DIR is de-asserted and the transceiver will wait until the Link de-asserts STP to resume

synchronous ULPI operation. The RESETB pin can also be pulsed low to reset the USB3320 and

return it to Synchronous Mode.

Table 6.6 Pin Definitions in 6 Pin Serial Mode

SIGNAL

CONNECTED

TO DIRECTION DESCRIPTION

tx_enable DATA[0] IN Active High transmit enable.

tx_data DATA[1] IN Tx differential data on DP/DM when tx_enable is high.

tx_se0 DATA[2] IN Tx SE0 on DP/DM when tx_enable is high.

interrupt DATA[3] OUT Asserted when any unmasked interrupt occurs. Active high.

rx_dp DATA[4] OUT Single ended receive data on DP.

rx_dm DATA[5] OUT Single ended receive data on DM.

rx_rcv DATA[6] OUT Differential receive data from DP and DM.

Reserved DATA[7] OUT Driven Low.