core/uart/uart_buf.c

   1 /*******************************************************************
   2     Copyright (C) 2009 FreakLabs
   3     All rights reserved.
   4
   5     Redistribution and use in source and binary forms, with or without
   6     modification, are permitted provided that the following conditions
   7     are met:
   8
   9     1. Redistributions of source code must retain the above copyright
  10        notice, this list of conditions and the following disclaimer.
  11     2. Redistributions in binary form must reproduce the above copyright
  12        notice, this list of conditions and the following disclaimer in the
  13        documentation and/or other materials provided with the distribution.
  14     3. Neither the name of the the copyright holder nor the names of its contributors
  15        may be used to endorse or promote products derived from this software
  16        without specific prior written permission.
  17
  18     THIS SOFTWARE IS PROVIDED BY THE THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
  19     ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21     ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  22     FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24     OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28     SUCH DAMAGE.
  29
  30     Originally written by Christopher Wang aka Akiba.
  31     Please post support questions to the FreakLabs forum.
  32 *******************************************************************/
  33
  34 /**************************************************************************/
  35 /*!
  36     @file     uart_buf.c
  37     @author   Christopher Wang (Freaklabs)
  38               Modified by: K. Townsend (microBuilder.eu)
  39     @date     19 May 2010
  40
  41     Original code taken from the FreakUSB Open Source USB Device Stack
  42     http://freaklabs.org/index.php/FreakUSB-Open-Source-USB-Device-Stack.html
  43
  44     If it works well, you can thank Akiba at Freaklabs.  If it fails
  45     miserably, you can blame me (since parts of it it were rather
  46     ungraciously modified). :-)
  47
  48 */
  49 /**************************************************************************/
  50
  51 #include "uart.h"
  52
  53 /**************************************************************************/
  54 /*!
  55   Initialises the RX FIFO buffer
  56 */
  57 /**************************************************************************/
  58 void uartRxBufferInit()
  59 {
  60   uart_pcb_t *pcb = uartGetPCB();
  61   pcb->rxfifo.len = 0;
  62 }
  63
  64 /**************************************************************************/
  65 /*!
  66   Read one byte out of the RX buffer. This function will return the byte
  67   located at the array index of the read pointer, and then increment the
  68   read pointer index.  If the read pointer exceeds the maximum buffer
  69   size, it will roll over to zero.
  70 */
  71 /**************************************************************************/
  72 uint8_t uartRxBufferRead()
  73 {
  74   uart_pcb_t *pcb = uartGetPCB();
  75   uint8_t data;
  76
  77   data = pcb->rxfifo.buf[pcb->rxfifo.rd_ptr];
  78   pcb->rxfifo.rd_ptr = (pcb->rxfifo.rd_ptr + 1) % CFG_UART_BUFSIZE;
  79   pcb->rxfifo.len--;
  80   return data;
  81 }
  82
  83 /**************************************************************************/
  84 /*!
  85   Read byte array from uart
  86  */
  87 /**************************************************************************/
  88 bool uartRxBufferReadArray(byte_t* rx, size_t* len)
  89 {
  90   uart_pcb_t *pcb = uartGetPCB();
  91   *len = 0;
  92
  93   while(pcb->rxfifo.len != 0)
  94   {
  95     (*rx) = uartRxBufferRead();
  96     (*len)++;
  97     rx++;
  98   }
  99
 100   return (*len != 0);
 101 }
 102
 103 /**************************************************************************/
 104 /*!
 105   Write one byte into the RX buffer. This function will write one
 106   byte into the array index specified by the write pointer and increment
 107   the write index. If the write index exceeds the max buffer size, then it
 108   will roll over to zero.
 109 */
 110 /**************************************************************************/
 111 void uartRxBufferWrite(uint8_t data)
 112 {
 113   uart_pcb_t *pcb = uartGetPCB();
 114
 115   pcb->rxfifo.buf[pcb->rxfifo.wr_ptr] = data;
 116   pcb->rxfifo.wr_ptr = (pcb->rxfifo.wr_ptr + 1) % CFG_UART_BUFSIZE;
 117   pcb->rxfifo.len++;
 118 }
 119
 120 /**************************************************************************/
 121 /*!
 122     Clear the fifo read and write pointers and set the length to zero.
 123 */
 124 /**************************************************************************/
 125 void uartRxBufferClearFIFO()
 126 {
 127   uart_pcb_t *pcb = uartGetPCB();
 128
 129   pcb->rxfifo.rd_ptr = 0;
 130   pcb->rxfifo.wr_ptr = 0;
 131   pcb->rxfifo.len = 0;
 132 }
 133
 134 /**************************************************************************/
 135 /*!
 136     Check whether there is any data pending on the RX buffer.
 137 */
 138 /**************************************************************************/
 139 uint8_t uartRxBufferDataPending()
 140 {
 141   uart_pcb_t *pcb = uartGetPCB();
 142
 143   if (pcb->rxfifo.len != 0)
 144   {
 145     return 1;
 146   }
 147
 148   return 0;
 149 }