Microchip Technology EVB-USB5744, Руководство пользователя

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EVB-USB5744 Evaluation Board User’s Guide
DS50002306B-page 12
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2015 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 3.1 Gen 1 registers). When using SMBus, the default config-
uration 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.