1 /*
2  * Author: Nandkishor Sonar
3  * Copyright (c) 2014 Intel Corporation.
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining
6  * a copy of this software and associated documentation files (the
7  * "Software"), to deal in the Software without restriction, including
8  * without limitation the rights to use, copy, modify, merge, publish,
9  * distribute, sublicense, and/or sell copies of the Software, and to
10  * permit persons to whom the Software is furnished to do so, subject to
11  * the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be
14  * included in all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
20  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
22  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23  */
24 
25 #pragma once
26 /**
27  * @file
28  * @brief Analog input/output
29  *
30  * AIO is the anlog input & output interface to libmraa. It is used to read or
31  * set the voltage applied to an AIO pin.
32  *
33  * @snippet analogin_a0.c Interesting
34  */
35 
36 #ifdef __cplusplus
37 extern "C" {
38 #endif
39 
40 #include <stdio.h>
41 #include <unistd.h>
42 #include <stdint.h>
43 
44 #include "common.h"
45 #include "gpio.h"
46 
47 /**
48  * Opaque pointer definition to the internal struct _aio. This context refers
49  * to one single AIO pin on the board.
50  */
51 typedef struct _aio* mraa_aio_context;
52 
53 /**
54  * Initialise an Analog input device, connected to the specified pin
55  *
56  * @param pin Channel number to read ADC inputs
57  * @returns aio context or NULL
58  */
59 mraa_aio_context mraa_aio_init(unsigned int pin);
60 
61 /**
62  * Read the input voltage. By default mraa will shift
63  * the raw value up or down to a 10 bit value.
64  *
65  * @param dev The AIO context
66  * @returns The current input voltage.
67  */
68 unsigned int mraa_aio_read(mraa_aio_context dev);
69 
70 /**
71  * Read the input voltage and return it as a normalized float (0.0f-1.0f).
72  *
73  * @param dev The AIO context
74  * @returns The current input voltage as a normalized float (0.0f-1.0f)
75  */
76 float mraa_aio_read_float(mraa_aio_context dev);
77 
78 /**
79  * Close the analog input context, this will free the memory for the context
80  *
81  * @param dev The AIO context
82  * @return Result of operation
83  */
84 mraa_result_t mraa_aio_close(mraa_aio_context dev);
85 
86 /**
87  * Set the bit value which mraa will shift the raw reading
88  * from the ADC to. I.e. 10bits
89  * @param dev the analog input context
90  * @param bits the bits the return from read should be i.e 10
91  *
92  * @return mraa result type
93  */
94 mraa_result_t mraa_aio_set_bit(mraa_aio_context dev, int bits);
95 
96 /**
97  * Gets the bit value mraa is shifting the analog read to.
98  * @param dev the analog input context
99  *
100  * @return bit value mraa is set return from the read function
101  */
102 int mraa_aio_get_bit(mraa_aio_context dev);
103 
104 #ifdef __cplusplus
105 }
106 #endif
107