 2015-2016 Microchip Technology Inc.

DS00002016B-page 23

USB5742

7.0

DEVICE INTERFACES

The USB5742 provides multiple interfaces for configuration and external memory access. This section details the vari-

ous device interfaces and their usage:

• SPI Master Interface

• SMBus Slave Interface

7.1

SPI Master Interface

The device is capable of code execution from an external SPI ROM. When configured for SPI Mode, on power up the

firmware looks for an external SPI flash device that contains a valid signature of 2DFU (device firmware upgrade) begin-

ning at address 0xFFFA. If a valid signature is found, then the external ROM is enabled and the code execution begins

at address 0x0000 in the external SPI device. If a valid signature is not found, then execution continues from internal

ROM.

7.2

SMBus Slave Interface

The device includes an integrated SMBus slave interface, which can be used to access internal device run time registers

or program the internal OTP memory. SMBus slave detection is accomplished by detection of pull-up resistors on both

the SMDAT and SMCLK signals. Refer to Section 3.4.1, "SPI/SMBus Configuration" for additional information.

Note:

For details on how to enable each interface, refer to Section 3.4.1, "SPI/SMBus Configuration".

For information on device connections, refer to Section 4.0, "Device Connections". For information on

device configuration, refer to Section 6.0, "Device Configuration".

Microchip provides a comprehensive software programming tool, Pro-Touch, for configuring the USB5742

functions, registers and OTP memory. All configuration is to be performed via the Pro-Touch programming

tool. For additional information on the Pro-Touch programming tool, refer to Software Libraries within Micro-

chip USB5742 product page at www.microchip.com/USB5742.

Note:

For SPI timing information, refer to Section 9.6.7, "SPI Timing".

Note:

All device configuration must be performed via the Pro-Touch Programming Tool. For additional information

on the Pro-Touch programming tool, refer to Software Libraries within Microchip USB5742 product page at

www.microchip.com/USB5742.