AVR Freaks

I see that this is an old thread, but I thought I'd post this here for anyone else having the same problem. 

I'm using the samE53 device, and the demo echo function would not work. 

It turns out, if you call atmel_start_init() as the demo code does, the USB echo will not work. 

If you sense the presence of the USB with a bit (USB_DETECT) in my code, and then call usb_init(); the USB echo will work.

Example code below:

#include <atmel_start.h>
#include <usb_start.h>
#include <stdio.h>

int main(void)
{
	char usb_serial_port_write_buffer[300];
	
	//Not using atmel_start_init();
	//As I am only using the USB if the user has selected it
	system_init();
	//atmel_start_init(); // Echo does not work with this enabled

	while(1)
	{
		//DEBUG
		if (gpio_get_pin_level(USB_DETECT)) // USB is plugged into the board
		{
			usb_init();
			gpio_set_pin_level(DIAG_LED_A,false);	// Set led A ON
			gpio_set_pin_level(DIAG_LED_B,true);	// Set led B OFF
			
			// cdcd_acm_example contains a while(1). Rem this line out to transmit below, unRem to test echo function
			//cdcd_acm_example();

			while (gpio_get_pin_level(USB_DETECT))	// while USB is connected
			{
				snprintf(usb_serial_port_write_buffer, sizeof(usb_serial_port_write_buffer), "Hello World!!!\r\n");
				cdcdf_acm_write((uint8_t *)usb_serial_port_write_buffer, strlen(usb_serial_port_write_buffer));
				delay_ms(250);
			}

			gpio_set_pin_level(DIAG_LED_A,true);	// Set led A OFF
			gpio_set_pin_level(DIAG_LED_B,false);	// Set led B ON
			usbdc_deinit();

		}
	}	// while
}

Hope this helps someone else avoid the hassles I just had. 

Rick