AN1047: EFM8 NOR Flash USB MSD

Reference Design

This application note describes the implementation of a USB

Mass Storage Device with an external NOR-Flash memory.

A method of logical to physical address mapping is also implemented in this reference

design. The full source code is included, which contains information about USB Mass

Storage Device class specification, SCSI, and the logical to physical transition for

EFM8UB1.

KEY POINTS

USB SPI

silabs.com | Smart. Connected. Energy-friendly. Rev. 0.1

The USB Mass Storage Device (MSD) class is one of the most widely supported device classes among the USB device classes native-

ly supported by popular operating systems. A USB device that supports this class can use the built-in drivers provided by the operating

system without the need to install or maintain any custom device drivers. The USB MSD Reference Design utilizes this widespread

support by providing device firmware for Silicon Labs USB microcontrollers that complies with the MSD class specification. In addition,

as any page of the NOR-Flash to be programmed must be erased first, a method of logical to physical address mapping is implemented

in the firmware to improve the performance and reliability of NOR-Flash arrays.

This document describes the various components of the device firmware in detail.

silabs.com | Smart. Connected. Energy-friendly. Rev. 0.1 | 1