uart_usb_lib.c

ATMEL 90usb128 USB CDC source,include USB protocol stack.

//!
//! @file uart_usb_lib.c,v
//!
//! Copyright (c) 2006 Atmel.
//!
//! Please read file license.txt for copyright notice.
//!
//! @brief This file controls the UART USB functions.
//!
//! @version 1.3 at90usb128-demo-cdc-1_0_3 $Id: uart_usb_lib.c,v 1.3 2006/03/17 13:06:22 rletendu Exp $
//!

/*_____ I N C L U D E S ____________________________________________________*/

#include "config.h"
#include "lib_mcu\usb\usb_drv.h"
#include "usb_descriptors.h"

#include "uart_usb_lib.h"

/*_____ M A C R O S ________________________________________________________*/

/*_____ D E F I N I T I O N ________________________________________________*/

Uchar tx_counter;
Uchar rx_counter;

/*_____ D E C L A R A T I O N ______________________________________________*/

/** 
  * @brief Initializes the uart_usb library
  */
void uart_usb_init(void)
{
  tx_counter = 0;
  rx_counter = 0;
}

/** 
  * @brief This function checks if a character has been received on the USB bus.
  * 
  * @return bit (true if a byte is ready to be read)
  */
bit uart_usb_test_hit(void)
{
  if (!rx_counter)
  {
    Usb_select_endpoint(RX_EP);
    if (Is_usb_receive_out())
    {
      rx_counter = Usb_byte_counter();
      if (!rx_counter)
		{
        Usb_ack_receive_out();
		}
    }
  }
  return (rx_counter!=0);
}

/** 
  * @brief This function reads one byte from the USB bus
  *
  * If one byte is present in the USB fifo, this byte is returned. If no data
  * is present in the USB fifo, this function waits for USB data.
  * 
  * @return U8 byte received
  */
char uart_usb_getchar(void)
{
  register Uchar data_rx;

  Usb_select_endpoint(RX_EP);
  if (!rx_counter) while (!uart_usb_test_hit());
  data_rx=Usb_read_byte();
  rx_counter--;
  if (!rx_counter) Usb_ack_receive_out();
  return data_rx;
}


/** 
  * @brief This function checks if the USB emission buffer is ready to accept at
  * at least 1 byte
  * 
  * @return Boolean. TRUE if the firmware can write a new byte to transmit.
  */
bit uart_usb_tx_ready(void)
{
  if (!Is_usb_write_enabled())
  {
    return FALSE;
  }
  return TRUE;
}

/** 
  * @brief This function fills the USB transmit buffer with the new data. This buffer
  * is sent if complete. To flush this buffer before waiting full, launch
  * the uart_usb_flush() function.
  * 
  * @param data_to_send 
  * 
  * @return 
  */
int uart_usb_putchar(int data_to_send)
{
  	Usb_select_endpoint(TX_EP);
  	while(!uart_usb_tx_ready()); // Wait Endpoint ready
	Usb_write_byte(data_to_send);
	tx_counter++;
  	if(!Is_usb_write_enabled()) //If Endpoint full -> flush
  	{
   	uart_usb_flush();
  	}
	return data_to_send;
}


/** 
  * @brief This function sends the data stored in the USB transmit buffer.
  * This function does nothing if there is no data in the buffer.
  */
void uart_usb_flush (void)
{
   Usb_select_endpoint(TX_EP);
   Usb_send_in();
	tx_counter = 0;

}