Paolo Patierno / SHTx

Humidity and Temperature Sensor - Sensirion SHT1x driver (with exported functions to use it from C code)

Dependents:   sht15_remote_monitoring

Fork of SHTx by Roy van Dam

i2c.cpp@2:7505a67001b4, 2015-11-15 (annotated)

Committer:
ppatierno
Date:
Sun Nov 15 15:13:08 2015 +0000
Revision:
2:7505a67001b4
Parent:
1:8465801be23f 
Added export layer to use SHTx from C code

Who changed what in which revision?

UserRevisionLine numberNew contents of line
NegativeBlack 1:8465801be23f 1 /**
NegativeBlack 1:8465801be23f 2 * Copyright (c) 2010 Roy van Dam <roy@negative-black.org>
NegativeBlack 1:8465801be23f 3 * All rights reserved.
NegativeBlack 1:8465801be23f 4 *
NegativeBlack 1:8465801be23f 5 * Redistribution and use in source and binary forms, with or without
NegativeBlack 1:8465801be23f 6 * modification, are permitted provided that the following conditions
NegativeBlack 1:8465801be23f 7 * are met:
NegativeBlack 1:8465801be23f 8 * 1. Redistributions of source code must retain the above copyright
NegativeBlack 1:8465801be23f 9 * notice, this list of conditions and the following disclaimer.
NegativeBlack 1:8465801be23f 10 * 2. Redistributions in binary form must reproduce the above copyright
NegativeBlack 1:8465801be23f 11 * notice, this list of conditions and the following disclaimer in the
NegativeBlack 1:8465801be23f 12 * documentation and/or other materials provided with the distribution.
NegativeBlack 1:8465801be23f 13 *
NegativeBlack 1:8465801be23f 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
NegativeBlack 1:8465801be23f 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
NegativeBlack 1:8465801be23f 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
NegativeBlack 1:8465801be23f 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
NegativeBlack 1:8465801be23f 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
NegativeBlack 1:8465801be23f 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
NegativeBlack 1:8465801be23f 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
NegativeBlack 1:8465801be23f 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
NegativeBlack 1:8465801be23f 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
NegativeBlack 1:8465801be23f 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
NegativeBlack 1:8465801be23f 24 * SUCH DAMAGE.
NegativeBlack 1:8465801be23f 25 */
NegativeBlack 1:8465801be23f 26
NegativeBlack 1:8465801be23f 27 #include "i2c.hpp"
NegativeBlack 1:8465801be23f 28
NegativeBlack 1:8465801be23f 29 namespace SHTx {
NegativeBlack 1:8465801be23f 30 I2C::I2C(PinName sda, PinName scl) :
NegativeBlack 1:8465801be23f 31 scl_pin(scl), sda_pin(sda), frequency(10) {
NegativeBlack 1:8465801be23f 32 this->sda_pin.output();
NegativeBlack 1:8465801be23f 33 this->scl_pin.output();
NegativeBlack 1:8465801be23f 34 }
NegativeBlack 1:8465801be23f 35
NegativeBlack 1:8465801be23f 36 void
NegativeBlack 1:8465801be23f 37 I2C::setFrequency(uint32_t hz) {
NegativeBlack 1:8465801be23f 38 this->frequency = (1000000 / hz);
NegativeBlack 1:8465801be23f 39 }
NegativeBlack 1:8465801be23f 40
NegativeBlack 1:8465801be23f 41 void
NegativeBlack 1:8465801be23f 42 I2C::start(void) {
NegativeBlack 1:8465801be23f 43 this->output();
NegativeBlack 1:8465801be23f 44 this->sda(1);
NegativeBlack 1:8465801be23f 45 this->scl(1);
NegativeBlack 1:8465801be23f 46 this->sda(0);
NegativeBlack 1:8465801be23f 47 this->scl(0);
NegativeBlack 1:8465801be23f 48 this->scl(1);
NegativeBlack 1:8465801be23f 49 this->sda(1);
NegativeBlack 1:8465801be23f 50 this->scl(0);
NegativeBlack 1:8465801be23f 51 }
NegativeBlack 1:8465801be23f 52
NegativeBlack 1:8465801be23f 53 void
NegativeBlack 1:8465801be23f 54 I2C::stop(void) {
NegativeBlack 1:8465801be23f 55 this->output();
NegativeBlack 1:8465801be23f 56 this->sda(0);
NegativeBlack 1:8465801be23f 57 this->scl(1);
NegativeBlack 1:8465801be23f 58 this->sda(1);
NegativeBlack 1:8465801be23f 59 }
NegativeBlack 1:8465801be23f 60
NegativeBlack 1:8465801be23f 61 bool
NegativeBlack 1:8465801be23f 62 I2C::wait(void) {
NegativeBlack 1:8465801be23f 63 bool ack = false;
NegativeBlack 1:8465801be23f 64
NegativeBlack 1:8465801be23f 65 this->input();
NegativeBlack 1:8465801be23f 66 for (uint8_t i = 0; i < 500 && !ack; i++) {
NegativeBlack 1:8465801be23f 67 wait_ms(1);
NegativeBlack 1:8465801be23f 68 ack = !this->sda_pin;
NegativeBlack 1:8465801be23f 69 }
NegativeBlack 1:8465801be23f 70
NegativeBlack 1:8465801be23f 71 return ack;
NegativeBlack 1:8465801be23f 72 }
NegativeBlack 1:8465801be23f 73
NegativeBlack 1:8465801be23f 74 void
NegativeBlack 1:8465801be23f 75 I2C::reset(void) {
NegativeBlack 1:8465801be23f 76 this->output();
NegativeBlack 1:8465801be23f 77 for (uint8_t i = 9; i; i--) {
NegativeBlack 1:8465801be23f 78 this->shift_out(1);
NegativeBlack 1:8465801be23f 79 }
NegativeBlack 1:8465801be23f 80 this->start();
NegativeBlack 1:8465801be23f 81 this->scl(1);
NegativeBlack 1:8465801be23f 82 }
NegativeBlack 1:8465801be23f 83
NegativeBlack 1:8465801be23f 84 bool
NegativeBlack 1:8465801be23f 85 I2C::write(uint8_t data) {
NegativeBlack 1:8465801be23f 86 bool ack;
NegativeBlack 1:8465801be23f 87
NegativeBlack 1:8465801be23f 88 this->output();
NegativeBlack 1:8465801be23f 89 for (uint8_t i = 8; i; i--) {
NegativeBlack 1:8465801be23f 90 this->shift_out(data & 0x80);
NegativeBlack 1:8465801be23f 91 data <<= 1;
NegativeBlack 1:8465801be23f 92 }
NegativeBlack 1:8465801be23f 93
NegativeBlack 1:8465801be23f 94 this->input();
NegativeBlack 1:8465801be23f 95 ack = !this->shift_in();
NegativeBlack 1:8465801be23f 96
NegativeBlack 1:8465801be23f 97 return ack;
NegativeBlack 1:8465801be23f 98 }
NegativeBlack 1:8465801be23f 99
NegativeBlack 1:8465801be23f 100 uint8_t
NegativeBlack 1:8465801be23f 101 I2C::read(bool ack) {
NegativeBlack 1:8465801be23f 102 uint8_t data = 0;
NegativeBlack 1:8465801be23f 103
NegativeBlack 1:8465801be23f 104 this->input();
NegativeBlack 1:8465801be23f 105 for (uint8_t i = 8; i; i--) {
NegativeBlack 1:8465801be23f 106 data <<= 1;
NegativeBlack 1:8465801be23f 107 data |= this->shift_in();
NegativeBlack 1:8465801be23f 108 }
NegativeBlack 1:8465801be23f 109
NegativeBlack 1:8465801be23f 110 this->output();
NegativeBlack 1:8465801be23f 111 this->shift_out(!ack);
NegativeBlack 1:8465801be23f 112
NegativeBlack 1:8465801be23f 113 return data;
NegativeBlack 1:8465801be23f 114 }
NegativeBlack 1:8465801be23f 115
NegativeBlack 1:8465801be23f 116 void
NegativeBlack 1:8465801be23f 117 I2C::output(void) {
NegativeBlack 1:8465801be23f 118 this->sda_pin.output();
NegativeBlack 1:8465801be23f 119 }
NegativeBlack 1:8465801be23f 120
NegativeBlack 1:8465801be23f 121 void
NegativeBlack 1:8465801be23f 122 I2C::input(void) {
NegativeBlack 1:8465801be23f 123 this->sda_pin.input();
NegativeBlack 1:8465801be23f 124 }
NegativeBlack 1:8465801be23f 125
NegativeBlack 1:8465801be23f 126 void
NegativeBlack 1:8465801be23f 127 I2C::sda(bool value) {
NegativeBlack 1:8465801be23f 128 this->sda_pin = value;
NegativeBlack 1:8465801be23f 129 wait_us(this->frequency);
NegativeBlack 1:8465801be23f 130 }
NegativeBlack 1:8465801be23f 131
NegativeBlack 1:8465801be23f 132 void
NegativeBlack 1:8465801be23f 133 I2C::scl(bool value) {
NegativeBlack 1:8465801be23f 134 this->scl_pin = value;
NegativeBlack 1:8465801be23f 135 wait_us(this->frequency);
NegativeBlack 1:8465801be23f 136 }
NegativeBlack 1:8465801be23f 137
NegativeBlack 1:8465801be23f 138 void
NegativeBlack 1:8465801be23f 139 I2C::shift_out(bool bit) {
NegativeBlack 1:8465801be23f 140 this->sda(bit);
NegativeBlack 1:8465801be23f 141 this->scl(1);
NegativeBlack 1:8465801be23f 142 this->scl(0);
NegativeBlack 1:8465801be23f 143 }
NegativeBlack 1:8465801be23f 144
NegativeBlack 1:8465801be23f 145 bool
NegativeBlack 1:8465801be23f 146 I2C::shift_in(void) {
NegativeBlack 1:8465801be23f 147 wait_us(this->frequency);
NegativeBlack 1:8465801be23f 148 this->scl(1);
NegativeBlack 1:8465801be23f 149 bool bit = this->sda_pin;
NegativeBlack 1:8465801be23f 150 this->scl(0);
NegativeBlack 1:8465801be23f 151 return bit;
NegativeBlack 1:8465801be23f 152 }
NegativeBlack 0:d55659b0c4a0 153 }