EVB-USB5744 Evaluation Board User’s Guide

DS50002306A-page 13

 2014 Microchip Technology Inc.

J10 in order to enable the SPI device.The external flash can be programmed using the Microchip

ProTouch MPT software tool which can be downloaded from the Microchip website at

http://www.Microchip.com/ProTouch.

2.1.2

SMBus

If an SPI Flash device is not found, the firmware checks if the SMBus is enabled. The

SMBus can operate in either legacy mode (USB 2.0 only) or advanced mode (access

to both USB 2.0 and USB 3.0 registers). When using SMBus, the default configuration

is for it to run in the advanced mode.

To select SMBus configuration, set the Config. Select switch to "Strap", position 2-3.

The green LED will light.

The SMBus must have correct pull up resistors applied by external circuitry to function

properly. The SMBus signals may be accessed at J8, pins 1 and 3.

Remember, if configured for SMBus operation the USB5744 will wait indefinitely for

data from the SMBus.

FIGURE 2-2:

SMBUS SELECT

2.1.3

Configuration Source - Internal Default

When the USB5744 does not detect a valid SPI Flash image or SMBus configuration

upon power-up, the EVB-USB5744 uses internal default register settings. It also sets

the Vendor ID, Product ID, Language ID, and Device ID, and additional settings from

internal ROM code.

2.1.4

Strapping Option

If configuration is not done through SPI, additional configuration is available through

two functions: CFG_BC and CFG_Non-Rem. The controls are configured by selecting

on of six resistor values for each pin. These are read by the USB5744 device and the

BC and Non-Rem behavior of the downstream facing ports are determined.

Note: Refer to the Protouch MPT User Manual on using this software to program

the configuration.