Microchip Technology EVB-USB5744, Руководство пользователя

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EVB-USB5744
EVALUATION BOARD
USER’S GUIDE

2015 Microchip Technology Inc. DS50002306B-page 11
Chapter 2. Getting Started
The Microchip EVB-USB5744 is designed for flexible configuration solutions. It can be
configured via default internal register settings, downloadable external firmware to an
onboard SPI Flash, through SMBus, or through the onboard configuration switches.
When configured with the default internal register settings, the device operates as a
USB 3.1 Gen 1 / USB 2.0 hub with four battery charge enabled USB ports and Micro-
chip’s standard VID/PID/DID settings.
2.1 CONFIGURATION
2.1.1 External SPI Flash
Upon power-up, the USB5744 first looks for an external SPI Flash device and a valid
signature in the flash. If one is found, the external ROM is enabled and code execution
is initiated from the external SPI device.
To select the SPI device, set the Config. Select switch to "SPI", position 1-2. The blue
LED will light. Note that the CFG_BC and CFG_Non-Rem options are now de-selected.
All configuration in SPI mode is done by the SPI.
FIGURE 2-1: SPI SELECT
The 10 k
Ω
pull-up resistors (R42 and R58) on the SPI device’s Write Protect (WPn) and Hold
(HOLDn) pins must also be populated in order to use external flash. The 10 k
Ω
pull-up resistor
(R61) on the SPI_CE_N pin of the USB5744 must also be populated in order to select 60MHz
SPI operation, as opposed to 30MHz operation. Additionally there must be a jumper placed on
Note: If the SPI Flash is not properly programmed or has an invalid signature, the
USB5744 will default to internal defaults even if the SPI Flash is selected.