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/**
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* Copyright (c) 2007 Colony Project
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following
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* conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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**/
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/**
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* @file serial.c
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* @brief Serial Input and Output
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*
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* Implementation of functions for serial input and output.
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*
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* @author Colony Project, CMU Robotics Club
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**/
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#include <avr/io.h> |
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#include "dragonfly_defs.h" |
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#include "serial.h" |
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unsigned char usb_initd=0; |
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#ifdef USE_STDIO
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#include <stdio.h> |
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/**
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* For use with fprintf() and related stdio functions
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**/
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FILE *usb_fd; |
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#endif
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/**
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* Initializes communication over the USB serial port.
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* This must be called before any other usb function
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* may be used.
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**/
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int usb_init() {
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//Set baud rate
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// - 115200 (both wired and wireless) is UBRR=8, U2X=1
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// - 9600 is U2X =1, UBRR = 107.
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if(usb_initd) {
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return ERROR_INIT_ALREADY_INITD;
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} |
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#if (USB_BAUD == 115200) |
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UBRR0H = 0x00;
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UBRR0L = 8;
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UCSR0A |= _BV(U2X0); |
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#elif (USB_BAUD == 9600) |
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UBRR0H = 0x00;
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UBRR0L = 103;
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UCSR0A |= _BV(U2X0); |
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#else //Baud rate is defined in the header file, we should not get here |
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return 0; |
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#endif
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/*Enable receiver and transmitter */
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UCSR0B |= (1<<RXEN0)|(1<<TXEN0); |
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/* Set frame format: 8data, 1stop bit, asynchronous normal mode */
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UCSR0C |= (1<<UCSZ00) | (1<<UCSZ01); |
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// if we have enabled the stdio stuff, then we init it here
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#ifdef USE_STDIO
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/* Open the stdio stream corresponding to this port */
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usb_fd = fdevopen(usb_putc, usb_getc); |
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#endif
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usb_initd = 1;
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return 0; |
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} |
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/**
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* Sends a character over USB.
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*
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* @param c the character to send
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* @return 0 for success, nonzero for failure
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**/
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int usb_putc(char c) { |
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if(!usb_initd)
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return ERROR_LIBRARY_NOT_INITD;
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// Wait until buffer is clear for sending
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loop_until_bit_is_set(UCSR0A, UDRE0); |
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// Load buffer with your character
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UDR0 = c; |
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return 0; |
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} |
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/**
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* Sends a sequence of characters over USB.
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*
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* @param s the string to send
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* @return 0 for success, nonzero for failure
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**/
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int usb_puts(char *s) { |
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char *t = s;
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if(!usb_initd)
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return ERROR_LIBRARY_NOT_INITD;
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while (*t != 0) { |
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usb_putc(*t); |
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t++; |
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} |
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return 0; |
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} |
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/**
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* Sends a sequence of characters from program space over USB.
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*
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* @param s the string to send
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*
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* @return 0 if init succesfull, an error code otherwise
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**/
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int usb_puts_P (PGM_P s) {
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char buf;
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if(!usb_initd)
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return ERROR_LIBRARY_NOT_INITD;
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while (memcpy_P (&buf, s, sizeof (char)), buf!=0) { |
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usb_putc (buf); |
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s++; |
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} |
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return 0; |
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} |
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/**
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* Returns the first character in the buffer received from USB.
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* This function blocks execution until a character has been received.
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* xbee_init must be called before this function may be used.
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*
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* @return the first character in the usb buffer, -1 on error
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*
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* @see usb_init, usb_getc_nb
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**/
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int usb_getc(void) { |
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if(!usb_initd)
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return -1; |
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// Wait for the receive buffer to be filled
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loop_until_bit_is_set(UCSR0A, RXC0); |
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// Read the receive buffer
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return UDR0;
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} |
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/**
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* Non blocking version of usb_getc. If a character is present in the buffer,
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* it is returned, otherwise -1 is returned immediately. usb_init must be
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* called before this function can be used.
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*
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* @param c the received character. This will be set if a character has
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* been received.
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*
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* @return -1 if no character is available, 0 otherwise, positive for error
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*
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* @see usb_init, usb_getc
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**/
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int usb_getc_nb(char *c) { |
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if(!usb_initd)
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return ERROR_LIBRARY_NOT_INITD;
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// check if the receive buffer is filled
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if (UCSR0A & _BV(RXC0)) {
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// Read the receive buffer
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(*c) = UDR0; |
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return 0; |
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} else {
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// Return empty
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return -1; |
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} |
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} |
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/*
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prints an int to serial
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code adapted from Chris Efstathiou's code (hendrix@otenet.gr)
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uses usb_putc
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*/
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/**
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* Prints an integer, converted to ASCII, to usb. usb_init must be called
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* before this function can be used.
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*
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* @param value the integer to print
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*
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* @return 0 if successful, nonzero otherwise
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*
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* @see usb_init, usb_putc
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**/
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int usb_puti(int value ) { |
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unsigned char usb_data[6]={'0','0','0','0','0','0' }, position=sizeof(usb_data), radix=10; |
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if(!usb_initd)
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return ERROR_LIBRARY_NOT_INITD;
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/* convert int to ascii */
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if(value<0) { |
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usb_putc('-');
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value=-value; |
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} |
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do {
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position--; |
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*(usb_data+position)=(value%radix)+'0';
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value/=radix; |
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} while(value);
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/* start displaying the number */
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for(;position<=(sizeof(usb_data)-1);position++) { |
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usb_putc(usb_data[position]); |
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} |
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return 0; |
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} |
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/**
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* Determines a hexadecimal digit in ASCII code.
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*
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* @param value the value of the digit (0<=value<=15)
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*
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* @return the hexadecimal digit in ASCII code, or '?'
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* if the input is invalid.
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**/
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uint8_t hex_digit (uint8_t value) |
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{ |
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if (value>15) return '?'; |
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// Postcondition: 0<=x<=15
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return "0123456789ABCDEF"[value]; |
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} |
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/**
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* Prints a fixed width hexadecimal representation of an unsigned
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* 16 bit integer in ASCII code to USB.
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* usb_init must be called before this function can be used.
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*
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* @param value the value to print
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*
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* @see usb_init, usb_puti, usb_puts, usb_puth8, hex_digit
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*
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* @return 0 if init succesfull, an error code otherwise
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**/
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int usb_puth16 (uint16_t value)
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{ |
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if(!usb_initd)
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return ERROR_LIBRARY_NOT_INITD;
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usb_putc (hex_digit((value >>12)&0xF)); |
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usb_putc (hex_digit((value >>8 )&0xF)); |
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usb_putc (hex_digit((value >>4 )&0xF)); |
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usb_putc (hex_digit( value &0xF));
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return 0; |
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} |
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/**
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* Prints a fixed width hexadecimal representation of an unsigned
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* 8 bit integer in ASCII code to USB.
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* usb_init must be called before this function can be used.
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*
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* @param value the value to print
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*
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* @see usb_init, usb_puti, usb_puts, usb_puth16, hex_digit
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*
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* @return 0 if init succesfull, an error code otherwise
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**/
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int usb_puth8(uint8_t value)
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{ |
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if(!usb_initd)
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return ERROR_LIBRARY_NOT_INITD;
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usb_putc (hex_digit ((value)>>4 &0xF)); |
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usb_putc (hex_digit ( value &0xF));
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return 0; |
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} |
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