Documentation improvements - put driver example code into its own section, fix incorr...
[pub/USBasp.git] / LUFA / Drivers / Peripheral / AVRU4U6U7 / ADC.h
1 /*
2 LUFA Library
3 Copyright (C) Dean Camera, 2010.
4
5 dean [at] fourwalledcubicle [dot] com
6 www.lufa-lib.org
7 */
8
9 /*
10 Copyright 2010 Dean Camera (dean [at] fourwalledcubicle [dot] com)
11
12 Permission to use, copy, modify, distribute, and sell this
13 software and its documentation for any purpose is hereby granted
14 without fee, provided that the above copyright notice appear in
15 all copies and that both that the copyright notice and this
16 permission notice and warranty disclaimer appear in supporting
17 documentation, and that the name of the author not be used in
18 advertising or publicity pertaining to distribution of the
19 software without specific, written prior permission.
20
21 The author disclaim all warranties with regard to this
22 software, including all implied warranties of merchantability
23 and fitness. In no event shall the author be liable for any
24 special, indirect or consequential damages or any damages
25 whatsoever resulting from loss of use, data or profits, whether
26 in an action of contract, negligence or other tortious action,
27 arising out of or in connection with the use or performance of
28 this software.
29 */
30
31 /** \file
32 * \brief ADC peripheral driver for the U7, U6 and U4 USB AVRs.
33 *
34 * On-chip Analogue-to-Digital converter (ADC) driver for supported U4, U6 and U7 model AVRs that contain an ADC
35 * peripheral internally.
36 *
37 * \note This file should not be included directly. It is automatically included as needed by the ADC driver
38 * dispatch header located in LUFA/Drivers/Peripheral/ADC.h.
39 */
40
41 /** \ingroup Group_ADC
42 * @defgroup Group_ADC_AVRU4U6U7 Series U4, U6 and U7 Model ADC Driver
43 *
44 * On-chip Analogue-to-Digital converter (ADC) driver for supported U4, U6 and U7 model AVRs that contain an ADC
45 * peripheral internally.
46 *
47 * \note This file should not be included directly. It is automatically included as needed by the ADC driver
48 * dispatch header located in LUFA/Drivers/Peripheral/ADC.h.
49 *
50 * \section Sec_ExampleUsage Example Usage
51 * The following snippet is an example of how this module may be used within a typical
52 * application.
53 *
54 * \code
55 * // Initialise the ADC driver before first use
56 * ADC_Init(ADC_FREE_RUNNING | ADC_PRESCALE_32);
57 *
58 * // Must setup the ADC channel to read beforehand
59 * ADC_SetupChannel(1);
60 *
61 * // Perform a single conversion of the ADC channel 1
62 * ADC_GetChannelReading(ADC_REFERENCE_AVCC | ADC_RIGHT_ADJUSTED | ADC_CHANNEL1);
63 * printf("Conversion Result: %d\r\n", ADC_GetResult());
64 *
65 * // Start reading ADC channel 1 in free running (continuous conversion) mode
66 * ADC_StartReading(ADC_REFERENCE_AVCC | ADC_RIGHT_ADJUSTED | ADC_CHANNEL1);
67 * while (!(ADC_IsReadingComplete())) {};
68 * printf("Conversion Result: %d\r\n", ADC_GetResult());
69 * \endcode
70 *
71 * @{
72 */
73
74 #ifndef __ADC_AVRU4U6U7_H__
75 #define __ADC_AVRU4U6U7_H__
76
77 /* Includes: */
78 #include "../../../Common/Common.h"
79
80 #include <avr/io.h>
81 #include <stdbool.h>
82
83 /* Enable C linkage for C++ Compilers: */
84 #if defined(__cplusplus)
85 extern "C" {
86 #endif
87
88 /* Preprocessor Checks: */
89 #if !defined(__INCLUDE_FROM_ADC_H)
90 #error Do not include this file directly. Include LUFA/Drivers/Peripheral/ADC.h instead.
91 #endif
92
93 /* Public Interface - May be used in end-application: */
94 /* Macros: */
95 /** \name ADC Reference Configuration Masks */
96 //@{
97 /** Reference mask, for using the voltage present at the AVR's AREF pin for the ADC reference. */
98 #define ADC_REFERENCE_AREF 0
99
100 /** Reference mask, for using the voltage present at the AVR's AVCC pin for the ADC reference. */
101 #define ADC_REFERENCE_AVCC (1 << REFS0)
102
103 /** Reference mask, for using the internally generated 2.56V reference voltage as the ADC reference. */
104 #define ADC_REFERENCE_INT2560MV ((1 << REFS1) | (1 << REFS0))
105 //@}
106
107 /** \name ADC Result Adjustment Configuration Masks */
108 //@{
109 /** Left-adjusts the 10-bit ADC result, so that the upper 8 bits of the value returned by the
110 * ADC_GetResult() macro contain the 8 most significant bits of the result.
111 */
112 #define ADC_LEFT_ADJUSTED (1 << ADLAR)
113
114 /** Right-adjusts the 10-bit ADC result, so that the lower 8 bits of the value returned by the
115 * ADC_GetResult() macro contain the 8 least significant bits of the result.
116 */
117 #define ADC_RIGHT_ADJUSTED (0 << ADLAR)
118 //@}
119
120 /** \name ADC Mode Configuration Masks */
121 //@{
122 /** Sets the ADC mode to free running, so that conversions take place continuously as fast as the ADC
123 * is capable of at the given input clock speed.
124 */
125 #define ADC_FREE_RUNNING (1 << ADATE)
126
127 /** Sets the ADC mode to single conversion, so that only a single conversion will take place before
128 * the ADC returns to idle.
129 */
130 #define ADC_SINGLE_CONVERSION (0 << ADATE)
131 //@}
132
133 /** \name ADC Prescaler Configuration Masks */
134 //@{
135 /** Sets the ADC input clock to prescale by a factor of 2 the AVR's system clock. */
136 #define ADC_PRESCALE_2 (1 << ADPS0)
137
138 /** Sets the ADC input clock to prescale by a factor of 4 the AVR's system clock. */
139 #define ADC_PRESCALE_4 (1 << ADPS1)
140
141 /** Sets the ADC input clock to prescale by a factor of 8 the AVR's system clock. */
142 #define ADC_PRESCALE_8 ((1 << ADPS0) | (1 << ADPS1))
143
144 /** Sets the ADC input clock to prescale by a factor of 16 the AVR's system clock. */
145 #define ADC_PRESCALE_16 (1 << ADPS2)
146
147 /** Sets the ADC input clock to prescale by a factor of 32 the AVR's system clock. */
148 #define ADC_PRESCALE_32 ((1 << ADPS2) | (1 << ADPS0))
149
150 /** Sets the ADC input clock to prescale by a factor of 64 the AVR's system clock. */
151 #define ADC_PRESCALE_64 ((1 << ADPS2) | (1 << ADPS1))
152
153 /** Sets the ADC input clock to prescale by a factor of 128 the AVR's system clock. */
154 #define ADC_PRESCALE_128 ((1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0))
155 //@}
156
157 /** \name ADC MUX Masks */
158 //@{
159 /** MUX mask define for the ADC0 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading. */
160 #define ADC_CHANNEL0 (0x00 << MUX0)
161
162 /** MUX mask define for the ADC1 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading. */
163 #define ADC_CHANNEL1 (0x01 << MUX0)
164
165 #if !(defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) || defined(__DOXYGEN__))
166 /** MUX mask define for the ADC2 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading.
167 *
168 * \note Not available on all AVR models.
169 */
170 #define ADC_CHANNEL2 (0x02 << MUX0)
171
172 /** MUX mask define for the ADC3 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading.
173 *
174 * \note Not available on all AVR models.
175 */
176 #define ADC_CHANNEL3 (0x03 << MUX0)
177 #endif
178
179 /** MUX mask define for the ADC4 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading. */
180 #define ADC_CHANNEL4 (0x04 << MUX0)
181
182 /** MUX mask define for the ADC5 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading. */
183 #define ADC_CHANNEL5 (0x05 << MUX0)
184
185 /** MUX mask define for the ADC6 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading. */
186 #define ADC_CHANNEL6 (0x06 << MUX0)
187
188 /** MUX mask define for the ADC7 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading. */
189 #define ADC_CHANNEL7 (0x07 << MUX0)
190
191 /** MUX mask define for the internal 1.1V bandgap channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading. */
192 #define ADC_1100MV_BANDGAP (0x1E << MUX0)
193
194 #if (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) || defined(__DOXYGEN__))
195 /** MUX mask define for the ADC8 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading.
196 *
197 * \note Not available on all AVR models.
198 */
199 #define ADC_CHANNEL8 ((1 << 8) | (0x00 << MUX0))
200
201 /** MUX mask define for the ADC9 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading.
202 *
203 * \note Not available on all AVR models.
204 */
205 #define ADC_CHANNEL9 ((1 << 8) | (0x01 << MUX0))
206
207 /** MUX mask define for the ADC10 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading.
208 *
209 * \note Not available on all AVR models.
210 */
211 #define ADC_CHANNEL10 ((1 << 8) | (0x02 << MUX0))
212
213 /** MUX mask define for the ADC11 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading.
214 *
215 * \note Not available on all AVR models.
216 */
217 #define ADC_CHANNEL11 ((1 << 8) | (0x03 << MUX0))
218
219 /** MUX mask define for the ADC12 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading.
220 *
221 * \note Not available on all AVR models.
222 */
223 #define ADC_CHANNEL12 ((1 << 8) | (0x04 << MUX0))
224
225 /** MUX mask define for the ADC13 channel of the ADC. See \ref ADC_StartReading and \ref ADC_GetChannelReading.
226 *
227 * \note Not available on all AVR models.
228 */
229 #define ADC_CHANNEL13 ((1 << 8) | (0x05 << MUX0))
230
231 /** MUX mask define for the internal temperature sensor channel of the ADC. See \ref ADC_StartReading and
232 * \ref ADC_GetChannelReading.
233 *
234 * \note Not available on all AVR models.
235 */
236 #define ADC_INT_TEMP_SENS ((1 << 8) | (0x07 << MUX0))
237 #endif
238 //@}
239
240 /* Inline Functions: */
241 /** Configures the given ADC channel, ready for ADC conversions. This function sets the
242 * associated port pin as an input and disables the digital portion of the I/O to reduce
243 * power consumption.
244 *
245 * \note This must only be called for ADC channels with are connected to a physical port
246 * pin of the AVR, denoted by its special alternative function ADCx.
247 * \n\n
248 *
249 * \note The channel number must be specified as an integer, and NOT a ADC_CHANNELx mask.
250 *
251 * \param[in] ChannelIndex ADC channel number to set up for conversions.
252 */
253 static inline void ADC_SetupChannel(const uint8_t ChannelIndex)
254 {
255 #if (defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB646__) || \
256 defined(__AVR_AT90USB1287__) || defined(__AVR_AT90USB647__) || \
257 defined(__AVR_ATmega32U6__))
258 DDRF &= ~(1 << ChannelIndex);
259 DIDR0 |= (1 << ChannelIndex);
260 #elif (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
261 if (ChannelIndex < 8)
262 {
263 DDRF &= ~(1 << ChannelIndex);
264 DIDR0 |= (1 << ChannelIndex);
265 }
266 else if (ChannelIndex == 8)
267 {
268 DDRD &= ~(1 << 4);
269 DIDR2 |= (1 << 0);
270 }
271 else if (ChannelIndex < 11)
272 {
273 DDRD &= ~(1 << (ChannelIndex - 3));
274 DIDR2 |= (1 << (ChannelIndex - 8));
275 }
276 else
277 {
278 DDRB &= ~(1 << (ChannelIndex - 7));
279 DIDR2 |= (1 << (ChannelIndex - 8));
280 }
281 #endif
282 }
283
284 /** De-configures the given ADC channel, re-enabling digital I/O mode instead of analog. This
285 * function sets the associated port pin as an input and re-enabled the digital portion of
286 * the I/O.
287 *
288 * \note This must only be called for ADC channels with are connected to a physical port
289 * pin of the AVR, denoted by its special alternative function ADCx.
290 * \n\n
291 *
292 * \note The channel number must be specified as an integer, and NOT a ADC_CHANNELx mask.
293 *
294 * \param[in] ChannelIndex ADC channel number to set up for conversions.
295 */
296 static inline void ADC_DisableChannel(const uint8_t ChannelIndex)
297 {
298 #if (defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB646__) || \
299 defined(__AVR_AT90USB1287__) || defined(__AVR_AT90USB647__) || \
300 defined(__AVR_ATmega32U6__))
301 DDRF &= ~(1 << ChannelIndex);
302 DIDR0 &= ~(1 << ChannelIndex);
303 #elif (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
304 if (ChannelIndex < 8)
305 {
306 DDRF &= ~(1 << ChannelIndex);
307 DIDR0 &= ~(1 << ChannelIndex);
308 }
309 else if (ChannelIndex == 8)
310 {
311 DDRD &= ~(1 << 4);
312 DIDR2 &= ~(1 << 0);
313 }
314 else if (ChannelIndex < 11)
315 {
316 DDRD &= ~(1 << (ChannelIndex - 3));
317 DIDR2 &= ~(1 << (ChannelIndex - 8));
318 }
319 else
320 {
321 DDRB &= ~(1 << (ChannelIndex - 7));
322 DIDR2 &= ~(1 << (ChannelIndex - 8));
323 }
324 #endif
325 }
326
327 /** Starts the reading of the given channel, but does not wait until the conversion has completed.
328 * Once executed, the conversion status can be determined via the \ref ADC_IsReadingComplete() macro and
329 * the result read via the \ref ADC_GetResult() macro.
330 *
331 * If the ADC has been initialized in free running mode, calling this function once will begin the repeated
332 * conversions. If the ADC is in single conversion mode (or the channel to convert from is to be changed),
333 * this function must be called each time a conversion is to take place.
334 *
335 * \param[in] MUXMask ADC channel mask, reference mask and adjustment mask.
336 */
337 static inline void ADC_StartReading(const uint16_t MUXMask)
338 {
339 ADMUX = MUXMask;
340
341 #if (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) || defined(__DOXYGEN__))
342 if (MUXMask & (1 << 8))
343 ADCSRB |= (1 << MUX5);
344 else
345 ADCSRB &= ~(1 << MUX5);
346 #endif
347
348 ADCSRA |= (1 << ADSC);
349 }
350
351 /** Indicates if the current ADC conversion is completed, or still in progress.
352 *
353 * \return Boolean false if the reading is still taking place, or true if the conversion is
354 * complete and ready to be read out with \ref ADC_GetResult().
355 */
356 static inline bool ADC_IsReadingComplete(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
357 static inline bool ADC_IsReadingComplete(void)
358 {
359 return ((ADCSRA & (1 << ADIF)) ? true : false);
360 }
361
362 /** Retrieves the conversion value of the last completed ADC conversion and clears the reading
363 * completion flag.
364 *
365 * \return The result of the last ADC conversion as an unsigned value.
366 */
367 static inline uint16_t ADC_GetResult(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
368 static inline uint16_t ADC_GetResult(void)
369 {
370 ADCSRA |= (1 << ADIF);
371 return ADC;
372 }
373
374 /** Performs a complete single reading from channel, including a polling spin-loop to wait for the
375 * conversion to complete, and the returning of the converted value.
376 *
377 * \note For free running mode, the automated conversions should be initialized with a single call
378 * to \ref ADC_StartReading() to select the channel and begin the automated conversions, and
379 * the results read directly from the \ref ADC_GetResult() instead to reduce overhead.
380 *
381 * \param[in] MUXMask Mask comprising of an ADC channel mask, reference mask and adjustment mask.
382 */
383 static inline uint16_t ADC_GetChannelReading(const uint16_t MUXMask) ATTR_WARN_UNUSED_RESULT;
384 static inline uint16_t ADC_GetChannelReading(const uint16_t MUXMask)
385 {
386 ADC_StartReading(MUXMask);
387
388 while (!(ADC_IsReadingComplete()));
389
390 return ADC_GetResult();
391 }
392
393 /** Initialises the ADC, ready for conversions. This must be called before any other ADC operations.
394 * The "mode" parameter should be a mask comprised of a conversion mode (free running or single) and
395 * prescaler masks.
396 *
397 * \param[in] Mode Mask of ADC prescale and mode settings.
398 */
399 static inline void ADC_Init(uint8_t Mode) ATTR_ALWAYS_INLINE;
400 static inline void ADC_Init(uint8_t Mode)
401 {
402 ADCSRA = ((1 << ADEN) | Mode);
403 }
404
405 /** Turns off the ADC. If this is called, any further ADC operations will require a call to
406 * \ref ADC_Init() before the ADC can be used again.
407 */
408 static inline void ADC_ShutDown(void) ATTR_ALWAYS_INLINE;
409 static inline void ADC_ShutDown(void)
410 {
411 ADCSRA = 0;
412 }
413
414 /** Indicates if the ADC is currently enabled.
415 *
416 * \return Boolean true if the ADC subsystem is currently enabled, false otherwise.
417 */
418 static inline bool ADC_GetStatus(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
419 static inline bool ADC_GetStatus(void)
420 {
421 return ((ADCSRA & (1 << ADEN)) ? true : false);
422 }
423
424 /* Disable C linkage for C++ Compilers: */
425 #if defined(__cplusplus)
426 }
427 #endif
428
429 #endif
430
431 /** @} */
432