sdcc/device/lib/_ser.c

   1 /*-------------------------------------------------------------------------
   2    _ser.c - this file contains a simple interrupt driven serial driver with
   3             buffer (no check for overflow!!!).
   4
   5    Copyright (C) 1999, Sandeep Dutta <sandeep.dutta AT ieee.org>
   6
   7    This library is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published by the
   9    Free Software Foundation; either version 2, or (at your option) any
  10    later version.
  11
  12    This library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this library; see the file COPYING. If not, write to the
  19    Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  20    MA 02110-1301, USA.
  21
  22    As a special exception, if you link this library with other files,
  23    some of which are compiled with SDCC, to produce an executable,
  24    this library does not by itself cause the resulting executable to
  25    be covered by the GNU General Public License. This exception does
  26    not however invalidate any other reasons why the executable file
  27    might be covered by the GNU General Public License.
  28 -------------------------------------------------------------------------*/
  29
  30 /*KA******************************************************************
  31 * PROJECT: PL-One/8052
  32 **********************************************************************
  33 * FILE: ser.c
  34 **********************************************************************
  35 * CHANGES:
  36 * date      author            description
  37 * --------------------------------------------------------------------
  38 * 04/26/99  we                final
  39 * 04/27/99  we                comments
  40 **********************************************************************
  41 * DESCRIPTION:
  42 * This file contains a simple interrupt driven serial driver with
  43 * buffer (no check for overflow!!!).
  44 **********************************************************************
  45 * FUNCTIONS DECLARED:
  46 * ser_init       Initialization; must be called first
  47 * ser_putc       output one char on the serial line
  48 * ser_getc       return a char if one has been received, else 0
  49 * ser_printString print a 0-terminated string
  50 * ser_charAvail  return 1 if a char arrived on serial line
  51 **********************************************************************
  52 * NOTE:
  53 * Remember to enable all interrupts (EA=1) outside of this module!!
  54 **********************************************************************
  55 * COMPILE TIME OPTIONS: -
  56 * DEBUG OPTIONS: -
  57 ******************************************************************KE*/
  58
  59 #include <8052.h>
  60
  61 #include "ser.h"
  62
  63 #define NON_BLOCKING
  64
  65 unsigned char __xdata ser_txIndexIn;
  66 unsigned char __xdata ser_txIndexOut;
  67 unsigned char __xdata ser_rxIndexIn;
  68 unsigned char __xdata ser_rxIndexOut;
  69
  70 unsigned char __xdata ser_txBuffer[0x100];
  71 unsigned char __xdata ser_rxBuffer[0x100];
  72
  73 static __bit ser_txBusy;
  74
  75 void
  76 ser_init(void)
  77 {
  78   ES = 0;
  79
  80   ser_txBusy     = 0;
  81
  82   ser_txIndexIn  = 0;
  83   ser_txIndexOut = 0;
  84   ser_rxIndexIn  = 0;
  85   ser_rxIndexOut = 0;
  86
  87   T2CON = 0x30;
  88
  89   /* Baudrate = 19200, oscillator frq. of my processor is 21.4772 MHz */
  90   RCAP2H = 0xFF;
  91   RCAP2L = 0xDD;
  92
  93   /* enable counter */
  94   T2CON = 0x34;
  95
  96   SCON = 0x50;
  97
  98   if (TI) {
  99     TI = 0;
 100   }
 101   if (RI) {
 102     RI = 0;
 103   }
 104
 105   ES=1;
 106 }
 107
 108 void
 109 ser_interrupt_handler(void) __interrupt (4) __using (1)
 110 {
 111   ES=0;
 112
 113   if (RI) {
 114     RI = 0;
 115     ser_rxBuffer[ser_rxIndexIn++] = SBUF;
 116   }
 117
 118   if (TI) {
 119     TI = 0;
 120     if (ser_txIndexIn == ser_txIndexOut) {
 121       ser_txBusy = 0;
 122     }
 123     else {
 124       SBUF = ser_txBuffer[ser_txIndexOut++];
 125     }
 126   }
 127
 128   ES=1;
 129 }
 130
 131 void
 132 ser_putc(unsigned char c)
 133 {
 134   ES=0;
 135
 136   if (ser_txBusy) {
 137     ser_txBuffer[ser_txIndexIn++] = c;
 138   }
 139   else {
 140     ser_txBusy = 1;
 141     SBUF = c;
 142   }
 143
 144   ES=1;
 145 }
 146
 147 unsigned char
 148 ser_getc(void)
 149 {
 150   char tmp;
 151
 152 #ifdef NON_BLOCKING
 153   if (ser_rxIndexIn != ser_rxIndexOut) {
 154     tmp = ser_rxBuffer[ser_rxIndexOut++];
 155   }
 156   else {
 157     tmp = 0;
 158   }
 159 #endif
 160
 161   return(tmp);
 162 }
 163
 164 void
 165 ser_printString(char *String)
 166 {
 167   while (*String) {
 168     ser_putc(*String++);
 169   }
 170 }
 171
 172 char
 173 ser_charAvail(void)
 174 {
 175   char ret = 0;
 176
 177   if (ser_rxIndexIn != ser_rxIndexOut) {
 178     ret = 1;
 179   }
 180
 181   return(ret);
 182 }
 183
 184 /*********************End of File************************************/