tmk_core/protocol/usb_hid/arduino-1.0.1/cores/arduino/wiring_analog.c

   1 /*
   2   wiring_analog.c - analog input and output
   3   Part of Arduino - http://www.arduino.cc/
   4
   5   Copyright (c) 2005-2006 David A. Mellis
   6
   7   This library is free software; you can redistribute it and/or
   8   modify it under the terms of the GNU Lesser General Public
   9   License as published by the Free Software Foundation; either
  10   version 2.1 of the License, or (at your option) any 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 GNU
  15   Lesser General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General
  18   Public License along with this library; if not, write to the
  19   Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20   Boston, MA  02111-1307  USA
  21
  22   Modified 28 September 2010 by Mark Sproul
  23
  24   $Id: wiring.c 248 2007-02-03 15:36:30Z mellis $
  25 */
  26
  27 #include "wiring_private.h"
  28 #include "pins_arduino.h"
  29
  30 uint8_t analog_reference = DEFAULT;
  31
  32 void analogReference(uint8_t mode)
  33 {
  34         // can't actually set the register here because the default setting
  35         // will connect AVCC and the AREF pin, which would cause a short if
  36         // there's something connected to AREF.
  37         analog_reference = mode;
  38 }
  39
  40 int analogRead(uint8_t pin)
  41 {
  42         uint8_t low, high;
  43
  44 #if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
  45         if (pin >= 54) pin -= 54; // allow for channel or pin numbers
  46 #elif defined(__AVR_ATmega32U4__)
  47         if (pin >= 18) pin -= 18; // allow for channel or pin numbers
  48 #elif defined(__AVR_ATmega1284__)
  49         if (pin >= 24) pin -= 24; // allow for channel or pin numbers
  50 #else
  51         if (pin >= 14) pin -= 14; // allow for channel or pin numbers
  52 #endif
  53
  54 #if defined(__AVR_ATmega32U4__)
  55         pin = analogPinToChannel(pin);
  56         ADCSRB = (ADCSRB & ~(1 << MUX5)) | (((pin >> 3) & 0x01) << MUX5);
  57 #elif defined(ADCSRB) && defined(MUX5)
  58         // the MUX5 bit of ADCSRB selects whether we're reading from channels
  59         // 0 to 7 (MUX5 low) or 8 to 15 (MUX5 high).
  60         ADCSRB = (ADCSRB & ~(1 << MUX5)) | (((pin >> 3) & 0x01) << MUX5);
  61 #endif
  62
  63         // set the analog reference (high two bits of ADMUX) and select the
  64         // channel (low 4 bits).  this also sets ADLAR (left-adjust result)
  65         // to 0 (the default).
  66 #if defined(ADMUX)
  67         ADMUX = (analog_reference << 6) | (pin & 0x07);
  68 #endif
  69
  70         // without a delay, we seem to read from the wrong channel
  71         //delay(1);
  72
  73 #if defined(ADCSRA) && defined(ADCL)
  74         // start the conversion
  75         sbi(ADCSRA, ADSC);
  76
  77         // ADSC is cleared when the conversion finishes
  78         while (bit_is_set(ADCSRA, ADSC));
  79
  80         // we have to read ADCL first; doing so locks both ADCL
  81         // and ADCH until ADCH is read.  reading ADCL second would
  82         // cause the results of each conversion to be discarded,
  83         // as ADCL and ADCH would be locked when it completed.
  84         low  = ADCL;
  85         high = ADCH;
  86 #else
  87         // we dont have an ADC, return 0
  88         low  = 0;
  89         high = 0;
  90 #endif
  91
  92         // combine the two bytes
  93         return (high << 8) | low;
  94 }
  95
  96 // Right now, PWM output only works on the pins with
  97 // hardware support.  These are defined in the appropriate
  98 // pins_*.c file.  For the rest of the pins, we default
  99 // to digital output.
 100 void analogWrite(uint8_t pin, int val)
 101 {
 102         // We need to make sure the PWM output is enabled for those pins
 103         // that support it, as we turn it off when digitally reading or
 104         // writing with them.  Also, make sure the pin is in output mode
 105         // for consistenty with Wiring, which doesn't require a pinMode
 106         // call for the analog output pins.
 107         pinMode(pin, OUTPUT);
 108         if (val == 0)
 109         {
 110                 digitalWrite(pin, LOW);
 111         }
 112         else if (val == 255)
 113         {
 114                 digitalWrite(pin, HIGH);
 115         }
 116         else
 117         {
 118                 switch(digitalPinToTimer(pin))
 119                 {
 120                         // XXX fix needed for atmega8
 121                         #if defined(TCCR0) && defined(COM00) && !defined(__AVR_ATmega8__)
 122                         case TIMER0A:
 123                                 // connect pwm to pin on timer 0
 124                                 sbi(TCCR0, COM00);
 125                                 OCR0 = val; // set pwm duty
 126                                 break;
 127                         #endif
 128
 129                         #if defined(TCCR0A) && defined(COM0A1)
 130                         case TIMER0A:
 131                                 // connect pwm to pin on timer 0, channel A
 132                                 sbi(TCCR0A, COM0A1);
 133                                 OCR0A = val; // set pwm duty
 134                                 break;
 135                         #endif
 136
 137                         #if defined(TCCR0A) && defined(COM0B1)
 138                         case TIMER0B:
 139                                 // connect pwm to pin on timer 0, channel B
 140                                 sbi(TCCR0A, COM0B1);
 141                                 OCR0B = val; // set pwm duty
 142                                 break;
 143                         #endif
 144
 145                         #if defined(TCCR1A) && defined(COM1A1)
 146                         case TIMER1A:
 147                                 // connect pwm to pin on timer 1, channel A
 148                                 sbi(TCCR1A, COM1A1);
 149                                 OCR1A = val; // set pwm duty
 150                                 break;
 151                         #endif
 152
 153                         #if defined(TCCR1A) && defined(COM1B1)
 154                         case TIMER1B:
 155                                 // connect pwm to pin on timer 1, channel B
 156                                 sbi(TCCR1A, COM1B1);
 157                                 OCR1B = val; // set pwm duty
 158                                 break;
 159                         #endif
 160
 161                         #if defined(TCCR2) && defined(COM21)
 162                         case TIMER2:
 163                                 // connect pwm to pin on timer 2
 164                                 sbi(TCCR2, COM21);
 165                                 OCR2 = val; // set pwm duty
 166                                 break;
 167                         #endif
 168
 169                         #if defined(TCCR2A) && defined(COM2A1)
 170                         case TIMER2A:
 171                                 // connect pwm to pin on timer 2, channel A
 172                                 sbi(TCCR2A, COM2A1);
 173                                 OCR2A = val; // set pwm duty
 174                                 break;
 175                         #endif
 176
 177                         #if defined(TCCR2A) && defined(COM2B1)
 178                         case TIMER2B:
 179                                 // connect pwm to pin on timer 2, channel B
 180                                 sbi(TCCR2A, COM2B1);
 181                                 OCR2B = val; // set pwm duty
 182                                 break;
 183                         #endif
 184
 185                         #if defined(TCCR3A) && defined(COM3A1)
 186                         case TIMER3A:
 187                                 // connect pwm to pin on timer 3, channel A
 188                                 sbi(TCCR3A, COM3A1);
 189                                 OCR3A = val; // set pwm duty
 190                                 break;
 191                         #endif
 192
 193                         #if defined(TCCR3A) && defined(COM3B1)
 194                         case TIMER3B:
 195                                 // connect pwm to pin on timer 3, channel B
 196                                 sbi(TCCR3A, COM3B1);
 197                                 OCR3B = val; // set pwm duty
 198                                 break;
 199                         #endif
 200
 201                         #if defined(TCCR3A) && defined(COM3C1)
 202                         case TIMER3C:
 203                                 // connect pwm to pin on timer 3, channel C
 204                                 sbi(TCCR3A, COM3C1);
 205                                 OCR3C = val; // set pwm duty
 206                                 break;
 207                         #endif
 208
 209                         #if defined(TCCR4A)
 210                         case TIMER4A:
 211                                 //connect pwm to pin on timer 4, channel A
 212                                 sbi(TCCR4A, COM4A1);
 213                                 #if defined(COM4A0)             // only used on 32U4
 214                                 cbi(TCCR4A, COM4A0);
 215                                 #endif
 216                                 OCR4A = val;    // set pwm duty
 217                                 break;
 218                         #endif
 219
 220                         #if defined(TCCR4A) && defined(COM4B1)
 221                         case TIMER4B:
 222                                 // connect pwm to pin on timer 4, channel B
 223                                 sbi(TCCR4A, COM4B1);
 224                                 OCR4B = val; // set pwm duty
 225                                 break;
 226                         #endif
 227
 228                         #if defined(TCCR4A) && defined(COM4C1)
 229                         case TIMER4C:
 230                                 // connect pwm to pin on timer 4, channel C
 231                                 sbi(TCCR4A, COM4C1);
 232                                 OCR4C = val; // set pwm duty
 233                                 break;
 234                         #endif
 235
 236                         #if defined(TCCR4C) && defined(COM4D1)
 237                         case TIMER4D:
 238                                 // connect pwm to pin on timer 4, channel D
 239                                 sbi(TCCR4C, COM4D1);
 240                                 #if defined(COM4D0)             // only used on 32U4
 241                                 cbi(TCCR4C, COM4D0);
 242                                 #endif
 243                                 OCR4D = val;    // set pwm duty
 244                                 break;
 245                         #endif
 246
 247
 248                         #if defined(TCCR5A) && defined(COM5A1)
 249                         case TIMER5A:
 250                                 // connect pwm to pin on timer 5, channel A
 251                                 sbi(TCCR5A, COM5A1);
 252                                 OCR5A = val; // set pwm duty
 253                                 break;
 254                         #endif
 255
 256                         #if defined(TCCR5A) && defined(COM5B1)
 257                         case TIMER5B:
 258                                 // connect pwm to pin on timer 5, channel B
 259                                 sbi(TCCR5A, COM5B1);
 260                                 OCR5B = val; // set pwm duty
 261                                 break;
 262                         #endif
 263
 264                         #if defined(TCCR5A) && defined(COM5C1)
 265                         case TIMER5C:
 266                                 // connect pwm to pin on timer 5, channel C
 267                                 sbi(TCCR5A, COM5C1);
 268                                 OCR5C = val; // set pwm duty
 269                                 break;
 270                         #endif
 271
 272                         case NOT_ON_TIMER:
 273                         default:
 274                                 if (val < 128) {
 275                                         digitalWrite(pin, LOW);
 276                                 } else {
 277                                         digitalWrite(pin, HIGH);
 278                                 }
 279                 }
 280         }
 281 }
 282