GT3200 datasheet(23/51 Pages) SMSC

23 / 51 page

USB2.0 PHY IC

SMSC GT3200, SMSC USB3250

Revision 1.3 (10-05-04)

DATASHEET

Chapter 7 Functional Overview

Figure 2.1 Block Diagram on page 2 shows the functional block diagram of the GT3200, SMSC

USB3250. Each of the functions is described in detail below.

7.1

Modes of Operation

The GT3200, SMSC USB3250 support two modes of operation. See Figure 7.1 for a block diagram

of the digital interface.

■

8-bit unidirectional mode. Selected when DATABUS16_8 = 0. CLKOUT runs at 60MHz. The 8-

bit transmit data bus uses the lower 8 bits of the DATA bus (ie, TXDATA[7:0] = DATA[7:0]). The

8-bit receive data bus uses the upper 8 bits of the DATA bus (ie, RXDATA[7:0] = DATA[15:8]).

■

16-bit bidirectional mode. Selected when DATABUS16_8 = 1. CLKOUT runs at 30MHz. An

additional signal (VALIDH) is used to identify whether the high byte of the respective 16-bit data

word is valid. The full 16-bit DATA bus is used for transmit and receive operations. If TXVALID

is asserted, then the DATA[15:0] bus accepts transmit data from the SIE. If TXVALID is deasserted,

then the DATA[15:0] bus presents received data to the SIE. VALIDH is undefined when

DATABUS16_8 = 0 (8-bit mode).

GT3200 Datasheet(PDF) 23 Page - SMSC Corporation