ASF USB host CDC

Human interface on SAM3X-EK:

Introduction

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

Startup

After loading firmware, connect the board (EVKxx,Xplain,...) to a USB device CDC. The example is a bridge between a USART from the main MCU and the USB host CDC interface.

• SAM3X USART used UART on J11 connector
• Led 3 (D5, red) is on when USB OTG cable is plugged in and Vbus is present
• Led 1 (D4, green) is continuously on when a device is connected
• Led 0 (D2, blue) blinks when USB host has checked and enabled CDC interface
  • 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 2 (D3, amber) is on during data transfer between CDC and UART

About example

The example uses the following module groups:

• Basic modules: Startup, board, clock, interrupt, power management
• USB host stack and CDC modules:
  services/usb/
  services/usb/uhc/
  services/usb/class/cdc/host/
• 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)