Microchip MCP342x ADC library
mcp342x.h@0:7dbf7356da6b, 2016-06-15 (annotated)
- Committer:
- antoniogonzalez
- Date:
- Wed Jun 15 10:37:24 2016 +0000
- Revision:
- 0:7dbf7356da6b
- Child:
- 1:c4da9889ff85
First commit
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
antoniogonzalez | 0:7dbf7356da6b | 1 | /** |
antoniogonzalez | 0:7dbf7356da6b | 2 | * Author: Antonio Gonzalez <antgon@cantab.net> |
antoniogonzalez | 0:7dbf7356da6b | 3 | * Copyright (c) 2016 The Francis Crick Institute. |
antoniogonzalez | 0:7dbf7356da6b | 4 | * |
antoniogonzalez | 0:7dbf7356da6b | 5 | * This program is free software: you can redistribute it and/or modify |
antoniogonzalez | 0:7dbf7356da6b | 6 | * it under the terms of the GNU General Public License as published by |
antoniogonzalez | 0:7dbf7356da6b | 7 | * the Free Software Foundation, either version 3 of the License, or |
antoniogonzalez | 0:7dbf7356da6b | 8 | * (at your option) any later version. |
antoniogonzalez | 0:7dbf7356da6b | 9 | * |
antoniogonzalez | 0:7dbf7356da6b | 10 | * This program is distributed in the hope that it will be useful, |
antoniogonzalez | 0:7dbf7356da6b | 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
antoniogonzalez | 0:7dbf7356da6b | 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
antoniogonzalez | 0:7dbf7356da6b | 13 | * GNU General Public License for more details. |
antoniogonzalez | 0:7dbf7356da6b | 14 | * |
antoniogonzalez | 0:7dbf7356da6b | 15 | * You should have received a copy of the GNU General Public License |
antoniogonzalez | 0:7dbf7356da6b | 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
antoniogonzalez | 0:7dbf7356da6b | 17 | */ |
antoniogonzalez | 0:7dbf7356da6b | 18 | |
antoniogonzalez | 0:7dbf7356da6b | 19 | #ifndef MCP342x_h |
antoniogonzalez | 0:7dbf7356da6b | 20 | #define MCP342x_h |
antoniogonzalez | 0:7dbf7356da6b | 21 | |
antoniogonzalez | 0:7dbf7356da6b | 22 | #include "mbed.h" |
antoniogonzalez | 0:7dbf7356da6b | 23 | |
antoniogonzalez | 0:7dbf7356da6b | 24 | /** |
antoniogonzalez | 0:7dbf7356da6b | 25 | * @brief Microchip analog-to-digital converter MCP3422/3/4 |
antoniogonzalez | 0:7dbf7356da6b | 26 | * |
antoniogonzalez | 0:7dbf7356da6b | 27 | * Library for using Microchip's family of analog-to-digital converters |
antoniogonzalez | 0:7dbf7356da6b | 28 | * MCP3422/3/4. Some features of these include: |
antoniogonzalez | 0:7dbf7356da6b | 29 | * - 12-, 14-, 16-, or 18-bit ADC. |
antoniogonzalez | 0:7dbf7356da6b | 30 | * - Two-wire I2C interface. |
antoniogonzalez | 0:7dbf7356da6b | 31 | * - Sampling rate, 3.75 (18-bit), 15 (16-bit), 60 (14-bit), or 240 |
antoniogonzalez | 0:7dbf7356da6b | 32 | * (12-bit) SPS. |
antoniogonzalez | 0:7dbf7356da6b | 33 | * - Two (MCP3422/3) or four (MCP3424) channels, differential input. |
antoniogonzalez | 0:7dbf7356da6b | 34 | * - Internal voltage reference, 2.048 V. |
antoniogonzalez | 0:7dbf7356da6b | 35 | * - Selectable PGA, x1, x2, x4, or x8. |
antoniogonzalez | 0:7dbf7356da6b | 36 | * - Conversion modes: one-shot or continuous. |
antoniogonzalez | 0:7dbf7356da6b | 37 | * |
antoniogonzalez | 0:7dbf7356da6b | 38 | * TODO: |
antoniogonzalez | 0:7dbf7356da6b | 39 | * - Implement 'conversion mode one-shot' |
antoniogonzalez | 0:7dbf7356da6b | 40 | * |
antoniogonzalez | 0:7dbf7356da6b | 41 | * Example: |
antoniogonzalez | 0:7dbf7356da6b | 42 | * @code |
antoniogonzalez | 0:7dbf7356da6b | 43 | * #include "mbed.h" |
antoniogonzalez | 0:7dbf7356da6b | 44 | * #include "mcp342x.h" |
antoniogonzalez | 0:7dbf7356da6b | 45 | * |
antoniogonzalez | 0:7dbf7356da6b | 46 | * I2C i2c(p9, p10); |
antoniogonzalez | 0:7dbf7356da6b | 47 | * MCP342x mcp_adc(&i2c); |
antoniogonzalez | 0:7dbf7356da6b | 48 | * |
antoniogonzalez | 0:7dbf7356da6b | 49 | * int main(){ |
antoniogonzalez | 0:7dbf7356da6b | 50 | * mcp_adc.set_channel(MCP342x::CHANNEL_2); |
antoniogonzalez | 0:7dbf7356da6b | 51 | * mcp_adc.set_pga(MCP342x::PGA_4); |
antoniogonzalez | 0:7dbf7356da6b | 52 | * mcp_adc.set_resolution(MCP342x::RESOLUTION_12); |
antoniogonzalez | 0:7dbf7356da6b | 53 | * |
antoniogonzalez | 0:7dbf7356da6b | 54 | * while(1){ |
antoniogonzalez | 0:7dbf7356da6b | 55 | * // Channel 2 was selected above. Read data from this channel. |
antoniogonzalez | 0:7dbf7356da6b | 56 | * long chan2_val = mcp_adc.read(); |
antoniogonzalez | 0:7dbf7356da6b | 57 | * |
antoniogonzalez | 0:7dbf7356da6b | 58 | * // Select now channel 1 and read it. |
antoniogonzalez | 0:7dbf7356da6b | 59 | * mcp_adc.set_channel(MCP342x::CHANNEL_1); |
antoniogonzalez | 0:7dbf7356da6b | 60 | * long chan1_val = mcp_adc.read(); |
antoniogonzalez | 0:7dbf7356da6b | 61 | * |
antoniogonzalez | 0:7dbf7356da6b | 62 | * printf("CH1 %i CH2 %i\r\n", chan1_val, chan2_val); |
antoniogonzalez | 0:7dbf7356da6b | 63 | * wait(5); |
antoniogonzalez | 0:7dbf7356da6b | 64 | * } |
antoniogonzalez | 0:7dbf7356da6b | 65 | * } |
antoniogonzalez | 0:7dbf7356da6b | 66 | * @endcode |
antoniogonzalez | 0:7dbf7356da6b | 67 | */ |
antoniogonzalez | 0:7dbf7356da6b | 68 | class MCP342x |
antoniogonzalez | 0:7dbf7356da6b | 69 | { |
antoniogonzalez | 0:7dbf7356da6b | 70 | public: |
antoniogonzalez | 0:7dbf7356da6b | 71 | // Registers. |
antoniogonzalez | 0:7dbf7356da6b | 72 | // The device has only one register, which is the configuration |
antoniogonzalez | 0:7dbf7356da6b | 73 | // byte. It consists of these bits: |
antoniogonzalez | 0:7dbf7356da6b | 74 | // 7 ~ready |
antoniogonzalez | 0:7dbf7356da6b | 75 | // 6-5 channel selection |
antoniogonzalez | 0:7dbf7356da6b | 76 | // 4 conversion mode (one-shot, continuous) |
antoniogonzalez | 0:7dbf7356da6b | 77 | // 3-2 sample rate selection (12, 14, 16, or 18) |
antoniogonzalez | 0:7dbf7356da6b | 78 | // 1-0 PGA gain selection (1x, 2x, 4x, or 8x) |
antoniogonzalez | 0:7dbf7356da6b | 79 | typedef enum { |
antoniogonzalez | 0:7dbf7356da6b | 80 | REG_PGA_Pos = 0, |
antoniogonzalez | 0:7dbf7356da6b | 81 | REG_RESOLUTION_Pos = 2, |
antoniogonzalez | 0:7dbf7356da6b | 82 | REG_MODE_Pos = 4, |
antoniogonzalez | 0:7dbf7356da6b | 83 | REG_CHANNEL_Pos = 5, |
antoniogonzalez | 0:7dbf7356da6b | 84 | REG_RDY_Pos = 7, |
antoniogonzalez | 0:7dbf7356da6b | 85 | |
antoniogonzalez | 0:7dbf7356da6b | 86 | REG_PGA_Clear = ~(0x3 << REG_PGA_Pos), |
antoniogonzalez | 0:7dbf7356da6b | 87 | REG_RESOLUTION_Clear = ~(0x3 << REG_RESOLUTION_Pos), |
antoniogonzalez | 0:7dbf7356da6b | 88 | REG_MODE_Clear = ~(0x1 << REG_MODE_Pos), |
antoniogonzalez | 0:7dbf7356da6b | 89 | REG_CHANNEL_Clear = ~(0x3 << REG_CHANNEL_Pos), |
antoniogonzalez | 0:7dbf7356da6b | 90 | REG_RDY_Clear = ~(0x1 << REG_RDY_Pos) |
antoniogonzalez | 0:7dbf7356da6b | 91 | } mcp342x_reg_t; |
antoniogonzalez | 0:7dbf7356da6b | 92 | |
antoniogonzalez | 0:7dbf7356da6b | 93 | // Programmable gain. |
antoniogonzalez | 0:7dbf7356da6b | 94 | typedef enum { |
antoniogonzalez | 0:7dbf7356da6b | 95 | PGA_1 = 0, |
antoniogonzalez | 0:7dbf7356da6b | 96 | PGA_2 = 1, |
antoniogonzalez | 0:7dbf7356da6b | 97 | PGA_4 = 2, |
antoniogonzalez | 0:7dbf7356da6b | 98 | PGA_8 = 3 |
antoniogonzalez | 0:7dbf7356da6b | 99 | } mcp342x_pga_t; |
antoniogonzalez | 0:7dbf7356da6b | 100 | |
antoniogonzalez | 0:7dbf7356da6b | 101 | // Resolution. |
antoniogonzalez | 0:7dbf7356da6b | 102 | typedef enum { |
antoniogonzalez | 0:7dbf7356da6b | 103 | RESOLUTION_12 = 0, |
antoniogonzalez | 0:7dbf7356da6b | 104 | RESOLUTION_14 = 1, |
antoniogonzalez | 0:7dbf7356da6b | 105 | RESOLUTION_16 = 2, |
antoniogonzalez | 0:7dbf7356da6b | 106 | RESOLUTION_18 = 3 |
antoniogonzalez | 0:7dbf7356da6b | 107 | } mcp342x_resolution_t; |
antoniogonzalez | 0:7dbf7356da6b | 108 | |
antoniogonzalez | 0:7dbf7356da6b | 109 | // Conversion mode. |
antoniogonzalez | 0:7dbf7356da6b | 110 | typedef enum { |
antoniogonzalez | 0:7dbf7356da6b | 111 | CONVERSION_MODE_ONESHOT = 0, |
antoniogonzalez | 0:7dbf7356da6b | 112 | CONVERSION_MODE_CONTINUOUS = 1 |
antoniogonzalez | 0:7dbf7356da6b | 113 | } mcp342x_conversion_mode_t; |
antoniogonzalez | 0:7dbf7356da6b | 114 | |
antoniogonzalez | 0:7dbf7356da6b | 115 | // Channels. |
antoniogonzalez | 0:7dbf7356da6b | 116 | typedef enum { |
antoniogonzalez | 0:7dbf7356da6b | 117 | CHANNEL_1 = 0, |
antoniogonzalez | 0:7dbf7356da6b | 118 | CHANNEL_2 = 1, |
antoniogonzalez | 0:7dbf7356da6b | 119 | CHANNEL_3 = 2, |
antoniogonzalez | 0:7dbf7356da6b | 120 | CHANNEL_4 = 3 |
antoniogonzalez | 0:7dbf7356da6b | 121 | } mcp342x_channel_t; |
antoniogonzalez | 0:7dbf7356da6b | 122 | |
antoniogonzalez | 0:7dbf7356da6b | 123 | /** |
antoniogonzalez | 0:7dbf7356da6b | 124 | * MCP342x constructor |
antoniogonzalez | 0:7dbf7356da6b | 125 | * |
antoniogonzalez | 0:7dbf7356da6b | 126 | * @param i2c Pointer to I2C |
antoniogonzalez | 0:7dbf7356da6b | 127 | * @param device_address Address for this sensor |
antoniogonzalez | 0:7dbf7356da6b | 128 | */ |
antoniogonzalez | 0:7dbf7356da6b | 129 | MCP342x(I2C *i2c, uint8_t device_address = 0b000); |
antoniogonzalez | 0:7dbf7356da6b | 130 | |
antoniogonzalez | 0:7dbf7356da6b | 131 | /** |
antoniogonzalez | 0:7dbf7356da6b | 132 | * Set channel to read from. |
antoniogonzalez | 0:7dbf7356da6b | 133 | * |
antoniogonzalez | 0:7dbf7356da6b | 134 | * @param channel Channel number |
antoniogonzalez | 0:7dbf7356da6b | 135 | */ |
antoniogonzalez | 0:7dbf7356da6b | 136 | void set_channel(mcp342x_channel_t channel); |
antoniogonzalez | 0:7dbf7356da6b | 137 | |
antoniogonzalez | 0:7dbf7356da6b | 138 | /** |
antoniogonzalez | 0:7dbf7356da6b | 139 | * Set conversion mode. |
antoniogonzalez | 0:7dbf7356da6b | 140 | * |
antoniogonzalez | 0:7dbf7356da6b | 141 | * @param mode Conversion mode. Options are |
antoniogonzalez | 0:7dbf7356da6b | 142 | * MCP342x::CONVERSION_MODE_ONESHOT or |
antoniogonzalez | 0:7dbf7356da6b | 143 | * MCP342x::CONVERSION_MODE_CONTINUOUS. |
antoniogonzalez | 0:7dbf7356da6b | 144 | */ |
antoniogonzalez | 0:7dbf7356da6b | 145 | void set_conversion_mode(mcp342x_conversion_mode_t mode); |
antoniogonzalez | 0:7dbf7356da6b | 146 | |
antoniogonzalez | 0:7dbf7356da6b | 147 | /** |
antoniogonzalez | 0:7dbf7356da6b | 148 | * Set resolution. |
antoniogonzalez | 0:7dbf7356da6b | 149 | * |
antoniogonzalez | 0:7dbf7356da6b | 150 | * @param resolution Resolution, one of |
antoniogonzalez | 0:7dbf7356da6b | 151 | * MCP342x::RESOLUTION_12, MCP342x::RESOLUTION_14, |
antoniogonzalez | 0:7dbf7356da6b | 152 | * MCP342x::RESOLUTION_16 or MCP342x::RESOLUTION_18. |
antoniogonzalez | 0:7dbf7356da6b | 153 | */ |
antoniogonzalez | 0:7dbf7356da6b | 154 | void set_resolution(mcp342x_resolution_t resolution); |
antoniogonzalez | 0:7dbf7356da6b | 155 | |
antoniogonzalez | 0:7dbf7356da6b | 156 | /** |
antoniogonzalez | 0:7dbf7356da6b | 157 | * Set programable gain amplifier. Options are |
antoniogonzalez | 0:7dbf7356da6b | 158 | * MCP342x::PGA_1, MCP342x::PGA_2, MCP342x::PGA_4, or MCP342x::PGA_8. |
antoniogonzalez | 0:7dbf7356da6b | 159 | */ |
antoniogonzalez | 0:7dbf7356da6b | 160 | void set_pga(mcp342x_pga_t pga); |
antoniogonzalez | 0:7dbf7356da6b | 161 | |
antoniogonzalez | 0:7dbf7356da6b | 162 | /** |
antoniogonzalez | 0:7dbf7356da6b | 163 | * Read the ADC value. The value will be that read from the channel |
antoniogonzalez | 0:7dbf7356da6b | 164 | * set previously (`set_channel`) |
antoniogonzalez | 0:7dbf7356da6b | 165 | * |
antoniogonzalez | 0:7dbf7356da6b | 166 | * @return Analog measurement in raw data (integer) |
antoniogonzalez | 0:7dbf7356da6b | 167 | */ |
antoniogonzalez | 0:7dbf7356da6b | 168 | long read(); |
antoniogonzalez | 0:7dbf7356da6b | 169 | |
antoniogonzalez | 0:7dbf7356da6b | 170 | /** |
antoniogonzalez | 0:7dbf7356da6b | 171 | * Read the ADC value in volts. The value will be that read from the |
antoniogonzalez | 0:7dbf7356da6b | 172 | * channel set previously (`set_channel`). |
antoniogonzalez | 0:7dbf7356da6b | 173 | * |
antoniogonzalez | 0:7dbf7356da6b | 174 | * The data are coded in two's complements format, and the final |
antoniogonzalez | 0:7dbf7356da6b | 175 | * voltage is also a function of the resolution and gain settings. |
antoniogonzalez | 0:7dbf7356da6b | 176 | * This function follows the equations presented in the device's |
antoniogonzalez | 0:7dbf7356da6b | 177 | * datasheet (Microchip DS22088C), Section 4.9. |
antoniogonzalez | 0:7dbf7356da6b | 178 | * |
antoniogonzalez | 0:7dbf7356da6b | 179 | * @return Analog measurement in volts (float) |
antoniogonzalez | 0:7dbf7356da6b | 180 | */ |
antoniogonzalez | 0:7dbf7356da6b | 181 | float read_volts(); |
antoniogonzalez | 0:7dbf7356da6b | 182 | |
antoniogonzalez | 0:7dbf7356da6b | 183 | private: |
antoniogonzalez | 0:7dbf7356da6b | 184 | uint8_t _address; |
antoniogonzalez | 0:7dbf7356da6b | 185 | I2C *_i2c; |
antoniogonzalez | 0:7dbf7356da6b | 186 | uint8_t _resolution; |
antoniogonzalez | 0:7dbf7356da6b | 187 | uint8_t _pga; |
antoniogonzalez | 0:7dbf7356da6b | 188 | char _configuration[1]; |
antoniogonzalez | 0:7dbf7356da6b | 189 | static const uint8_t _device_code = 0b1101; // Hardcoded in factory |
antoniogonzalez | 0:7dbf7356da6b | 190 | void _write_configuration(); |
antoniogonzalez | 0:7dbf7356da6b | 191 | }; |
antoniogonzalez | 0:7dbf7356da6b | 192 | |
antoniogonzalez | 0:7dbf7356da6b | 193 | //void mcp342x_start_conversion(void); For one-shot mode. |
antoniogonzalez | 0:7dbf7356da6b | 194 | |
antoniogonzalez | 0:7dbf7356da6b | 195 | #endif |