Christoph Hofer / Mbed 2 deprecated minimal_working_example

Minimal working example to demonstrate I2C with SI7021 sensor

Dependencies:   BLE_API mbed nRF51822

main.cpp@2:fd94a7e87ac5, 2016-12-10 (annotated)

Committer:
ghost22
Date:
Sat Dec 10 16:17:12 2016 +0000
Revision:
2:fd94a7e87ac5
Parent:
1:bca7ac3aedac 
Fix of I2C

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ghost22 0:d843c5528596 1 /*
ghost22 0:d843c5528596 2
ghost22 0:d843c5528596 3 Copyright (c) 2012-2014 RedBearLab
ghost22 0:d843c5528596 4
ghost22 0:d843c5528596 5 Permission is hereby granted, free of charge, to any person obtaining a copy of this software
ghost22 0:d843c5528596 6 and associated documentation files (the "Software"), to deal in the Software without restriction,
ghost22 0:d843c5528596 7 including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
ghost22 0:d843c5528596 8 and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
ghost22 0:d843c5528596 9 subject to the following conditions:
ghost22 0:d843c5528596 10 The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
ghost22 0:d843c5528596 11
ghost22 0:d843c5528596 12 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
ghost22 0:d843c5528596 13 INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
ghost22 0:d843c5528596 14 PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
ghost22 0:d843c5528596 15 FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ghost22 0:d843c5528596 16 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
ghost22 0:d843c5528596 17
ghost22 0:d843c5528596 18 */
ghost22 0:d843c5528596 19
christoph 1:bca7ac3aedac 20 #include <string.h>
ghost22 0:d843c5528596 21 #include "mbed.h"
ghost22 0:d843c5528596 22 #include "wire.h"
ghost22 0:d843c5528596 23
ghost22 0:d843c5528596 24 #define SCL 7
ghost22 0:d843c5528596 25 #define SDA 6
ghost22 0:d843c5528596 26
christoph 1:bca7ac3aedac 27 #define DEV_ADDR 0x80
ghost22 0:d843c5528596 28
ghost22 0:d843c5528596 29 TwoWire Wire = TwoWire(NRF_TWI0);
ghost22 0:d843c5528596 30
christoph 1:bca7ac3aedac 31 Serial pc(USBTX, USBRX);
ghost22 0:d843c5528596 32
christoph 1:bca7ac3aedac 33 uint16_t ReadHumidity(void);
christoph 1:bca7ac3aedac 34 int16_t ReadTemperature(void);
ghost22 0:d843c5528596 35
ghost22 0:d843c5528596 36 int main(void)
ghost22 0:d843c5528596 37 {
christoph 1:bca7ac3aedac 38 uint16_t rh;
christoph 1:bca7ac3aedac 39 int16_t t;
christoph 1:bca7ac3aedac 40 char buf[200];
christoph 1:bca7ac3aedac 41
ghost22 0:d843c5528596 42 pc.baud(9600);
ghost22 0:d843c5528596 43 wait(5);
christoph 1:bca7ac3aedac 44
ghost22 0:d843c5528596 45 Wire.begin(SCL, SDA, TWI_FREQUENCY_100K);
christoph 1:bca7ac3aedac 46
ghost22 0:d843c5528596 47 while(1)
ghost22 0:d843c5528596 48 {
christoph 1:bca7ac3aedac 49 rh = ReadHumidity();
christoph 1:bca7ac3aedac 50 t = ReadTemperature();
christoph 1:bca7ac3aedac 51
christoph 1:bca7ac3aedac 52 sprintf(buf,"RH=%d, T=%d\r\n\0",rh,t);
christoph 1:bca7ac3aedac 53
christoph 1:bca7ac3aedac 54 pc.printf(buf);
christoph 1:bca7ac3aedac 55 wait(5);
ghost22 0:d843c5528596 56 }
ghost22 0:d843c5528596 57 }
ghost22 0:d843c5528596 58
ghost22 0:d843c5528596 59
ghost22 0:d843c5528596 60
ghost22 0:d843c5528596 61
christoph 1:bca7ac3aedac 62 uint16_t ReadHumidity(void)
christoph 1:bca7ac3aedac 63 {
christoph 1:bca7ac3aedac 64 uint16_t msbyte=0;
christoph 1:bca7ac3aedac 65 uint16_t lsbyte=0;
christoph 1:bca7ac3aedac 66 uint16_t checksum=0;
christoph 1:bca7ac3aedac 67 uint16_t rhcode=0;
christoph 1:bca7ac3aedac 68
christoph 1:bca7ac3aedac 69 Wire.beginTransmission(DEV_ADDR);
ghost22 2:fd94a7e87ac5 70
ghost22 2:fd94a7e87ac5 71 Wire.write(0xE5);
ghost22 2:fd94a7e87ac5 72
ghost22 2:fd94a7e87ac5 73 Wire.endTransmission(0);
ghost22 0:d843c5528596 74
christoph 1:bca7ac3aedac 75 Wire.requestFrom(DEV_ADDR+1, 3);
christoph 1:bca7ac3aedac 76
christoph 1:bca7ac3aedac 77 if(Wire.available())
christoph 1:bca7ac3aedac 78 {
christoph 1:bca7ac3aedac 79 msbyte = Wire.read();
christoph 1:bca7ac3aedac 80 }
christoph 1:bca7ac3aedac 81 if(Wire.available())
christoph 1:bca7ac3aedac 82 {
christoph 1:bca7ac3aedac 83 lsbyte = Wire.read();
christoph 1:bca7ac3aedac 84 }
christoph 1:bca7ac3aedac 85 if(Wire.available())
christoph 1:bca7ac3aedac 86 {
christoph 1:bca7ac3aedac 87 checksum = Wire.read();
christoph 1:bca7ac3aedac 88 }
christoph 1:bca7ac3aedac 89
christoph 1:bca7ac3aedac 90 rhcode = (((msbyte*256.0)+lsbyte)*125.0/65536.0-6.0)*100.0;
christoph 1:bca7ac3aedac 91
christoph 1:bca7ac3aedac 92 if(rhcode<=0)
christoph 1:bca7ac3aedac 93 {
christoph 1:bca7ac3aedac 94 rhcode=0;
christoph 1:bca7ac3aedac 95 }
christoph 1:bca7ac3aedac 96 if(rhcode>=100*100)
christoph 1:bca7ac3aedac 97 {
christoph 1:bca7ac3aedac 98 rhcode=100*100;
christoph 1:bca7ac3aedac 99 }
christoph 1:bca7ac3aedac 100 return rhcode;
christoph 1:bca7ac3aedac 101 }
christoph 1:bca7ac3aedac 102 int16_t ReadTemperature(void)
christoph 1:bca7ac3aedac 103 {
christoph 1:bca7ac3aedac 104 int16_t msbyte=0;
christoph 1:bca7ac3aedac 105 int16_t lsbyte=0;
christoph 1:bca7ac3aedac 106 int16_t checksum=0;
christoph 1:bca7ac3aedac 107
christoph 1:bca7ac3aedac 108 Wire.beginTransmission(DEV_ADDR);
ghost22 2:fd94a7e87ac5 109
ghost22 2:fd94a7e87ac5 110 Wire.write(0xE3);
ghost22 2:fd94a7e87ac5 111
ghost22 2:fd94a7e87ac5 112 Wire.endTransmission(0);
ghost22 0:d843c5528596 113
christoph 1:bca7ac3aedac 114 Wire.requestFrom(DEV_ADDR+1, 3);
christoph 1:bca7ac3aedac 115
christoph 1:bca7ac3aedac 116 if(Wire.available())
christoph 1:bca7ac3aedac 117 {
christoph 1:bca7ac3aedac 118 msbyte = Wire.read();
christoph 1:bca7ac3aedac 119 }
christoph 1:bca7ac3aedac 120 if(Wire.available())
christoph 1:bca7ac3aedac 121 {
christoph 1:bca7ac3aedac 122 lsbyte = Wire.read();
christoph 1:bca7ac3aedac 123 }
christoph 1:bca7ac3aedac 124 if(Wire.available())
christoph 1:bca7ac3aedac 125 {
christoph 1:bca7ac3aedac 126 checksum = Wire.read();
christoph 1:bca7ac3aedac 127 }
christoph 1:bca7ac3aedac 128
christoph 1:bca7ac3aedac 129 return (((msbyte*256.0)+lsbyte)*175.72/65536.0-46.85)*100.0;
christoph 1:bca7ac3aedac 130 }
ghost22 0:d843c5528596 131
ghost22 0:d843c5528596 132