Colony

/**

 * Copyright (c) 2007 Colony Project

 * 

 * Permission is hereby granted, free of charge, to any person

 * obtaining a copy of this software and associated documentation

 * files (the "Software"), to deal in the Software without

 * restriction, including without limitation the rights to use,

 * copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following

 * conditions:

 * 

 * The above copyright notice and this permission notice shall be

 * included in all copies or substantial portions of the Software.

 * 

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES

 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

 * OTHER DEALINGS IN THE SOFTWARE.

 **/

/**

 * @file serial.c

 * @brief Serial Input and Output

 *

 * Implementation of functions for serial input and output.

 *

 * @author Colony Project, CMU Robotics Club

 **/

#include <avr/io.h>

#include "dragonfly_defs.h"

#include "serial.h"

unsigned char usb_initd=0;

#ifdef USE_STDIO

#include <stdio.h>

/**

 * For use with fprintf() and related stdio functions

 **/

FILE *usb_fd;

#endif

/**

 * Initializes communication over the USB serial port.

 * This must be called before any other usb function

 * may be used.

 **/

int usb_init() {

  //Set baud rate

  // - 115200 (both wired and wireless) is UBRR=8, U2X=1

  // - 9600 is U2X =1, UBRR = 107.

  if(usb_initd) {

    return ERROR_INIT_ALREADY_INITD;

  }

#if (USB_BAUD == 115200)

  UBRR0H = 0x00;

  UBRR0L = 8;

  UCSR0A |= _BV(U2X0);

#elif (USB_BAUD == 9600)

  UBRR0H = 0x00;

  UBRR0L = 103;

  UCSR0A |= _BV(U2X0);

#else //Baud rate is defined in the header file, we should not get here

  return 0;

#endif

  /*Enable receiver and transmitter */

  UCSR0B |= (1<<RXEN0)|(1<<TXEN0);

  /* Set frame format: 8data, 1stop bit, asynchronous normal mode */

  UCSR0C |= (1<<UCSZ00) | (1<<UCSZ01);

  // if we have enabled the stdio stuff, then we init it here

#ifdef USE_STDIO

  /* Open the stdio stream corresponding to this port */

  usb_fd = fdevopen(usb_putc, usb_getc);

#endif

  usb_initd = 1;

  return 0;

}

/**

 * Sends a character over USB.

 *

 * @param c the character to send

 * @return 0 for success, nonzero for failure

 **/

int usb_putc(char c) {

  if(!usb_initd)

    return ERROR_LIBRARY_NOT_INITD;

  // Wait until buffer is clear for sending

  loop_until_bit_is_set(UCSR0A, UDRE0);

  // Load buffer with your character

  UDR0 = c;

  return 0;

}

/**

 * Sends a sequence of characters over USB.

 *

 * @param s the string to send

 * @return 0 for success, nonzero for failure

 **/

int usb_puts(char *s) {

  char *t = s;

  if(!usb_initd)

    return ERROR_LIBRARY_NOT_INITD;

  while (*t != 0) {

    usb_putc(*t);

    t++;

  }

  return 0;

}

/**

 * Sends a sequence of characters from program space over USB.

 *

 * @param s the string to send

 *

 * @return 0 if init succesfull, an error code otherwise

 **/

int usb_puts_P (PGM_P s) {

    char buf;

    if(!usb_initd)

      return ERROR_LIBRARY_NOT_INITD;

    while (memcpy_P (&buf, s, sizeof (char)), buf!=0) {

        usb_putc (buf);

        s++;

    }

    return 0;

}

/**

 * Returns the first character in the buffer received from USB.

 * This function blocks execution until a character has been received.

 * xbee_init must be called before this function may be used.

 * 

 * @return the first character in the usb buffer, -1 on error

 *

 * @see usb_init, usb_getc_nb

 **/

int usb_getc(void) {

  if(!usb_initd)

    return -1;

  // Wait for the receive buffer to be filled

  loop_until_bit_is_set(UCSR0A, RXC0);

  // Read the receive buffer

  return UDR0;

}

/**

 * Non blocking version of usb_getc. If a character is present in the buffer,

 * it is returned, otherwise -1 is returned immediately. usb_init must be

 * called before this function can be used.

 *

 * @param c the received character. This will be set if a character has

 * been received.

 * 

 * @return -1 if no character is available, 0 otherwise, positive for error

 * 

 * @see usb_init, usb_getc

 **/

int usb_getc_nb(char *c) {

  if(!usb_initd)

    return ERROR_LIBRARY_NOT_INITD;

  // check if the receive buffer is filled

  if (UCSR0A & _BV(RXC0)) {

    // Read the receive buffer

    (*c) = UDR0;

    return 0;

  } else {

    // Return empty

    return -1;

  }

}

/*

  prints an int to serial

  code adapted from Chris Efstathiou's code (hendrix@otenet.gr)

  uses usb_putc

*/

/**

 * Prints an integer, converted to ASCII, to usb. usb_init must be called

 * before this function can be used.

 *

 * @param value the integer to print

 * 

 * @return 0 if successful, nonzero otherwise

 *

 * @see usb_init, usb_putc

 **/

int usb_puti(int value ) {

  unsigned char usb_data[6]={'0','0','0','0','0','0' }, position=sizeof(usb_data), radix=10; 

  if(!usb_initd)

    return ERROR_LIBRARY_NOT_INITD;

  /* convert int to ascii  */ 

  if(value<0) { 

    usb_putc('-'); 

    value=-value; 

  }    

  do { 

    position--; 

    *(usb_data+position)=(value%radix)+'0'; 

    value/=radix;  

  } while(value); 

  /* start displaying the number */

  for(;position<=(sizeof(usb_data)-1);position++) {

    usb_putc(usb_data[position]);

  }

  return 0;

}

/**

 * Determines a hexadecimal digit in ASCII code.

 *

 * @param value the value of the digit (0<=value<=15)

 * 

 * @return the hexadecimal digit in ASCII code, or '?'

 * if the input is invalid.

 **/

uint8_t hex_digit (uint8_t value)

{

    if (value>15) return '?';

    // Postcondition: 0<=x<=15

    return "0123456789ABCDEF"[value];

}

/**

 * Prints a fixed width hexadecimal representation of an unsigned

 * 16 bit integer in ASCII code to USB.

 * usb_init must be called before this function can be used.

 *

 * @param value the value to print

 * 

 * @see usb_init, usb_puti, usb_puts, usb_puth8, hex_digit

 *

 * @return 0 if init succesfull, an error code otherwise

 **/

int usb_puth16 (uint16_t value)

{

    if(!usb_initd)

      return ERROR_LIBRARY_NOT_INITD;

    usb_putc (hex_digit((value >>12)&0xF));

    usb_putc (hex_digit((value >>8 )&0xF));

    usb_putc (hex_digit((value >>4 )&0xF));

    usb_putc (hex_digit( value      &0xF));

    return 0;

}

/**

 * Prints a fixed width hexadecimal representation of an unsigned

 * 8 bit integer in ASCII code to USB.

 * usb_init must be called before this function can be used.

 *

 * @param value the value to print

 * 

 * @see usb_init, usb_puti, usb_puts, usb_puth16, hex_digit

 *

 * @return 0 if init succesfull, an error code otherwise

 **/

int usb_puth8(uint8_t value)

{

    if(!usb_initd)

      return ERROR_LIBRARY_NOT_INITD;

    usb_putc (hex_digit ((value)>>4 &0xF));

    usb_putc (hex_digit ( value     &0xF));

    return 0;

}