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ASF USB host mass storage

Human interface on SAM L21 Xplained Pro:

Introduction

This example shows how to implement a USB host mass storage on Atmel MCU with USB module.

Startup

After loading firmware, connect the board (EVKxx,XPlain,...) to a U-Disk (FAT/FAT32 are supported). This example creates a file "uhi_msc_test.txt" on all present U-disks.

  • Led 0 is on when it's host and there is no device connected
  • Led 0 blinks when a device is enumerated and USB in idle mode
    • The blink is slow (1s) with low speed device
    • The blink is normal (0.5s) with full speed device
    • The blink is fast (0.25s) with high speed device
  • Led 0 is on when a read or write access is on going, and keep on if a LUN test is successful
  • Led 0 is off when a LUN test is unsuccessful
  • Button SW0 allows to enter the device in suspend mode with remote wakeup feature authorized
  • Only SW0 button can be used to wakeup USB device in suspend mode

About example

The example uses the following module groups:

  • Basic modules: Startup, board, clock, interrupt, power management
  • USB host stack and MSC modules:
    services/usb/
    services/usb/uhc/
    services/usb/class/msc/host/
  • Thirdparty modules:
    thirdparty/fatfs
  • Specific implementation:
    • main.c,
      initializes clock
      initializes interrupt
      manages UI
    • specific implementation for each target "./examples/product_board/":
      • conf_foo.h configuration of each module
      • ui.c implement of user's interface (buttons, leds)