sanguino/cores/arduino/wiring_analog.c

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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__) || defined(__AVR_ATmega644p__)
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

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