Alan Millard / Mbed 2 deprecated BeautifulMemeProjectBT

Bluetooth communication for flocking.

Dependencies:   mbed

Fork of BeautifulMemeProject by James Hilder

PsiSwarm/i2c.cpp@0:8a5497a2e366, 2015-10-03 (annotated)

Committer:
jah128
Date:
Sat Oct 03 22:48:50 2015 +0000
Revision:
0:8a5497a2e366
Child:
5:598298aa4900
Initial commit of PsiSwarm API and example code

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jah128 0:8a5497a2e366 1 /* University of York Robotics Laboratory PsiSwarm Library: I2C Source File
jah128 0:8a5497a2e366 2 *
jah128 0:8a5497a2e366 3 * File: i2c.cpp
jah128 0:8a5497a2e366 4 *
jah128 0:8a5497a2e366 5 * (C) Dr James Hilder, Dept. Electronics & Computer Science, University of York
jah128 0:8a5497a2e366 6 *
jah128 0:8a5497a2e366 7 * PsiSwarm Library Version: 0.2
jah128 0:8a5497a2e366 8 *
jah128 0:8a5497a2e366 9 * September 2015
jah128 0:8a5497a2e366 10 *
jah128 0:8a5497a2e366 11 */
jah128 0:8a5497a2e366 12
jah128 0:8a5497a2e366 13 #include "psiswarm.h"
jah128 0:8a5497a2e366 14
jah128 0:8a5497a2e366 15 char gpio_byte0;
jah128 0:8a5497a2e366 16 char gpio_byte1;
jah128 0:8a5497a2e366 17 char user_id_set = 0;
jah128 0:8a5497a2e366 18 char wheel_enc_set = 0;
jah128 0:8a5497a2e366 19 char switch_set = 0;
jah128 0:8a5497a2e366 20
jah128 0:8a5497a2e366 21 char emitter_byte = 0x00;
jah128 0:8a5497a2e366 22
jah128 0:8a5497a2e366 23 Timeout update_timeout;
jah128 0:8a5497a2e366 24
jah128 0:8a5497a2e366 25 DigitalOut test_led(LED2);
jah128 0:8a5497a2e366 26
jah128 0:8a5497a2e366 27 char test;
jah128 0:8a5497a2e366 28
jah128 0:8a5497a2e366 29 void IF_set_IR_emitter_output(char emitter, char state)
jah128 0:8a5497a2e366 30 {
jah128 0:8a5497a2e366 31 if(emitter <3) {
jah128 0:8a5497a2e366 32 if(state == 0) {
jah128 0:8a5497a2e366 33 char shift = 1 << emitter;
jah128 0:8a5497a2e366 34 emitter_byte &= (0xFF - shift);
jah128 0:8a5497a2e366 35 }
jah128 0:8a5497a2e366 36 if(state == 1) {
jah128 0:8a5497a2e366 37 char shift = 1 << emitter;
jah128 0:8a5497a2e366 38 emitter_byte |= shift;
jah128 0:8a5497a2e366 39 }
jah128 0:8a5497a2e366 40 char data[2];
jah128 0:8a5497a2e366 41 data [0] = 0x0A; //Write to OLAT register
jah128 0:8a5497a2e366 42 data [1] = emitter_byte; //GP0-3 are outputs on aux expansion IC
jah128 0:8a5497a2e366 43 //pc.printf("%c\n", emitter_byte);
jah128 0:8a5497a2e366 44 primary_i2c.write(AUX_IC_ADDRESS,data,2,false);
jah128 0:8a5497a2e366 45 }
jah128 0:8a5497a2e366 46 }
jah128 0:8a5497a2e366 47
jah128 0:8a5497a2e366 48 void IF_set_base_LED(char state)
jah128 0:8a5497a2e366 49 {
jah128 0:8a5497a2e366 50 if(state == 0) {
jah128 0:8a5497a2e366 51 emitter_byte &= 0xF7;
jah128 0:8a5497a2e366 52 } else emitter_byte |= 0x08;
jah128 0:8a5497a2e366 53 char data[2];
jah128 0:8a5497a2e366 54 data [0] = 0x0A; //Write to OLAT register
jah128 0:8a5497a2e366 55 data [1] = emitter_byte; //GP0-3 are outputs on aux expansion IC
jah128 0:8a5497a2e366 56 primary_i2c.write(AUX_IC_ADDRESS,data,2,false);
jah128 0:8a5497a2e366 57
jah128 0:8a5497a2e366 58 }
jah128 0:8a5497a2e366 59
jah128 0:8a5497a2e366 60 unsigned short IF_read_IR_adc_value(char adc, char index)
jah128 0:8a5497a2e366 61 {
jah128 0:8a5497a2e366 62 char address = ADC1_ADDRESS;
jah128 0:8a5497a2e366 63 if(adc == 2) address=ADC2_ADDRESS;
jah128 0:8a5497a2e366 64 // Returns the raw sensor value for the IR sensor defined by index (range 0-7).
jah128 0:8a5497a2e366 65 short value = 0;
jah128 0:8a5497a2e366 66 // Read a single value from the ADC
jah128 0:8a5497a2e366 67 if(index<8) {
jah128 0:8a5497a2e366 68 char apb[1];
jah128 0:8a5497a2e366 69 char data[2];
jah128 0:8a5497a2e366 70 switch(index) {
jah128 0:8a5497a2e366 71 case 0:
jah128 0:8a5497a2e366 72 apb[0]=0x80;
jah128 0:8a5497a2e366 73 break;
jah128 0:8a5497a2e366 74 case 1:
jah128 0:8a5497a2e366 75 apb[0]=0x90;
jah128 0:8a5497a2e366 76 break;
jah128 0:8a5497a2e366 77 case 2:
jah128 0:8a5497a2e366 78 apb[0]=0xA0;
jah128 0:8a5497a2e366 79 break;
jah128 0:8a5497a2e366 80 case 3:
jah128 0:8a5497a2e366 81 apb[0]=0xB0;
jah128 0:8a5497a2e366 82 break;
jah128 0:8a5497a2e366 83 case 4:
jah128 0:8a5497a2e366 84 apb[0]=0xC0;
jah128 0:8a5497a2e366 85 break;
jah128 0:8a5497a2e366 86 case 5:
jah128 0:8a5497a2e366 87 apb[0]=0xD0;
jah128 0:8a5497a2e366 88 break;
jah128 0:8a5497a2e366 89 case 6:
jah128 0:8a5497a2e366 90 apb[0]=0xE0;
jah128 0:8a5497a2e366 91 break;
jah128 0:8a5497a2e366 92 case 7:
jah128 0:8a5497a2e366 93 apb[0]=0xF0;
jah128 0:8a5497a2e366 94 break;
jah128 0:8a5497a2e366 95 }
jah128 0:8a5497a2e366 96 primary_i2c.write(address,apb,1,false);
jah128 0:8a5497a2e366 97 primary_i2c.read(address,data,2,false);
jah128 0:8a5497a2e366 98 value=((data[0] % 16)<<8)+data[1];
jah128 0:8a5497a2e366 99 if(value > 4096) value=4096;
jah128 0:8a5497a2e366 100 value=4096-value;
jah128 0:8a5497a2e366 101 }
jah128 0:8a5497a2e366 102 return value;
jah128 0:8a5497a2e366 103 }
jah128 0:8a5497a2e366 104
jah128 0:8a5497a2e366 105 char IF_setup_led_expansion_ic(void)
jah128 0:8a5497a2e366 106 {
jah128 0:8a5497a2e366 107 //LED expansion IC is PCA9555
jah128 0:8a5497a2e366 108 //Address is 0100 001x (0x42) {defined by LED_IC_ADDRESS}
jah128 0:8a5497a2e366 109 //All 16 entries are outputs as they drive LEDs; the relevant registers are 2&3 (output port registers) and 6&7 (config. registers: a 0=output)
jah128 0:8a5497a2e366 110 //Message structure: {Address-RW}{Command}{Port 0}{Port 1}
jah128 0:8a5497a2e366 111 //Command bytes: 00000010 (0x02) = Write to output port
jah128 0:8a5497a2e366 112 //Command bytes: 00000110 (0x06) = Write to config registers
jah128 0:8a5497a2e366 113 //Note that for the LEDs, 0 = on, 1 = off
jah128 0:8a5497a2e366 114 //Port 0 = LED 1:4 Red:Green
jah128 0:8a5497a2e366 115 //Port 1 = LED 5:8 Red:Green
jah128 0:8a5497a2e366 116 char data [3];
jah128 0:8a5497a2e366 117 data [0] = 0x06; //Write config registers
jah128 0:8a5497a2e366 118 data [1] = 0x00; //All 8 pins in port 0 are outputs (0)
jah128 0:8a5497a2e366 119 data [2] = 0x00; //All 8 pins in port 1 are outputs (0)
jah128 0:8a5497a2e366 120 primary_i2c.write(LED_IC_ADDRESS,data,3,false);
jah128 0:8a5497a2e366 121
jah128 0:8a5497a2e366 122 //Turn all LEDs on
jah128 0:8a5497a2e366 123 data [0] = 0x02; //Write to output port
jah128 0:8a5497a2e366 124 data [1] = 0x00; //Enable LED1-4 (both colours)
jah128 0:8a5497a2e366 125 data [2] = 0x00; //Enable LED5-8 (both colours)
jah128 0:8a5497a2e366 126 primary_i2c.write(LED_IC_ADDRESS,data,3,false);
jah128 0:8a5497a2e366 127
jah128 0:8a5497a2e366 128 wait(0.05);
jah128 0:8a5497a2e366 129 //Turn all LEDs off
jah128 0:8a5497a2e366 130 data [0] = 0x02; //Write to output port
jah128 0:8a5497a2e366 131 data [1] = 0xFF; //Enable LED1-4 (both colours)
jah128 0:8a5497a2e366 132 data [2] = 0xFF; //Enable LED5-8 (both colours)
jah128 0:8a5497a2e366 133 return primary_i2c.write(LED_IC_ADDRESS,data,3,false);
jah128 0:8a5497a2e366 134 }
jah128 0:8a5497a2e366 135
jah128 0:8a5497a2e366 136 //Returns 0 if successful, 1 if test mode button pressed
jah128 0:8a5497a2e366 137 void IF_setup_gpio_expansion_ic(void)
jah128 0:8a5497a2e366 138 {
jah128 0:8a5497a2e366 139 //Main GPIO expansion IC is PCA9555
jah128 0:8a5497a2e366 140 //Address is 0100 000x (0x40) {defined by GPIO_IC_ADDRESS}
jah128 0:8a5497a2e366 141 //All 16 entries are inputs; the relevant registers are 0&1 (input port registers), 4&5 (polarity inv. registers) and 6&7 (config. registers: a 0=output)
jah128 0:8a5497a2e366 142 //Message structure: {Address-RW}{Command}{Port 0}{Port 1}
jah128 0:8a5497a2e366 143 //Command bytes: 00000010 (0x02) = Write to output port
jah128 0:8a5497a2e366 144 //Command bytes: 00000110 (0x06) = Write to config registers
jah128 0:8a5497a2e366 145 //Note that for the LEDs, 0 = on, 1 = off
jah128 0:8a5497a2e366 146 //Port 0 = PGDL; PGDR; PGDIR; UP; DOWN; LEFT; RIGHT; CENTER
jah128 0:8a5497a2e366 147 //Port 1 = ENC_LA; ENC_LB; ENC_RA; ENC_RB; ID0; ID1; ID2; ID3
jah128 0:8a5497a2e366 148 char data [3];
jah128 0:8a5497a2e366 149 data [0] = 0x06; //Write config registers
jah128 0:8a5497a2e366 150 data [1] = 0xFF; //All 8 pins in port 0 are inputs (1)
jah128 0:8a5497a2e366 151 data [2] = 0xFF; //All 8 pins in port 1 are inputs (1)
jah128 0:8a5497a2e366 152 if(primary_i2c.write(GPIO_IC_ADDRESS,data,3,false) != 0) {
jah128 0:8a5497a2e366 153 system_warnings += 2;
jah128 0:8a5497a2e366 154 debug("- WARNING: No I2C acknowledge for main GPIO IC\n");
jah128 0:8a5497a2e366 155 }
jah128 0:8a5497a2e366 156 //Set all inputs to polarity-inverted (so a logic low = 1)
jah128 0:8a5497a2e366 157 data [0] = 0x04; //Write to polarity inversion ports
jah128 0:8a5497a2e366 158 data [1] = 0xFF; //Invert polarity of all bits in input port 0
jah128 0:8a5497a2e366 159 data [2] = 0xFF; //Invert polarity of all bits in input port 1
jah128 0:8a5497a2e366 160 primary_i2c.write(GPIO_IC_ADDRESS,data,3,false);
jah128 0:8a5497a2e366 161
jah128 0:8a5497a2e366 162 wait(0.01);
jah128 0:8a5497a2e366 163
jah128 0:8a5497a2e366 164 //Read data
jah128 0:8a5497a2e366 165 char read_data[2];
jah128 0:8a5497a2e366 166 char command[1]; //Command to read from input port 0
jah128 0:8a5497a2e366 167 command[0]=0;
jah128 0:8a5497a2e366 168 primary_i2c.write(GPIO_IC_ADDRESS,command,1,false);
jah128 0:8a5497a2e366 169 primary_i2c.read(GPIO_IC_ADDRESS,read_data,2,false);
jah128 0:8a5497a2e366 170 gpio_byte0 = read_data[0];
jah128 0:8a5497a2e366 171 //char ret_val = (gpio_byte0 & 0xF8) >> 3; //Returns a >0 value if a button is being pushed
jah128 0:8a5497a2e366 172 gpio_byte1 = read_data[1];
jah128 0:8a5497a2e366 173 IF_parse_gpio_byte0(gpio_byte0);
jah128 0:8a5497a2e366 174 IF_parse_gpio_byte1(gpio_byte1);
jah128 0:8a5497a2e366 175 //Setup interrupt handler for GPIO interrupts
jah128 0:8a5497a2e366 176 gpio_interrupt.mode(PullUp);
jah128 0:8a5497a2e366 177 gpio_interrupt.rise(&IF_handle_gpio_interrupt);
jah128 0:8a5497a2e366 178 //pc.printf("%c %c",gpio_byte0,gpio_byte1);
jah128 0:8a5497a2e366 179
jah128 0:8a5497a2e366 180 //Secondary GPIO expansion IC is MCP23009
jah128 0:8a5497a2e366 181 //Address is 0100 111 (0x4E) {defined by AUX_IC_ADDRESS}
jah128 0:8a5497a2e366 182 //GP0,1,2,3 are outputs for driving infrared emitters and the base LED
jah128 0:8a5497a2e366 183 //IODIR register wants to be 0xF0 (1=input, 0=output)
jah128 0:8a5497a2e366 184 data [0] = 0x00; //Write to IODIR register
jah128 0:8a5497a2e366 185 data [1] = 0xF0; //Set GP0-3 as outputs
jah128 0:8a5497a2e366 186 primary_i2c.write(AUX_IC_ADDRESS,data,2,false);
jah128 0:8a5497a2e366 187
jah128 0:8a5497a2e366 188 if(primary_i2c.write(AUX_IC_ADDRESS,data,2,false) != 0) {
jah128 0:8a5497a2e366 189 system_warnings += 4;
jah128 0:8a5497a2e366 190 debug("- WARNING: No I2C acknowledge for aux GPIO IC\n");
jah128 0:8a5497a2e366 191 }
jah128 0:8a5497a2e366 192 data [0] = 0x06; //Write to GPPU register
jah128 0:8a5497a2e366 193 data [1] = 0x0F; //Set GP0-3 as active pull-up outputs
jah128 0:8a5497a2e366 194 primary_i2c.write(AUX_IC_ADDRESS,data,2,false);
jah128 0:8a5497a2e366 195
jah128 0:8a5497a2e366 196 //My interrupt is not so reliable: poll with a 50ms timeout in case interrupts aren't handled
jah128 0:8a5497a2e366 197 update_timeout.attach_us(&IF_update_gpio_inputs,50000);
jah128 0:8a5497a2e366 198 //return ret_val;
jah128 0:8a5497a2e366 199 }
jah128 0:8a5497a2e366 200
jah128 0:8a5497a2e366 201 void IF_parse_gpio_byte0(char byte)
jah128 0:8a5497a2e366 202 {
jah128 0:8a5497a2e366 203 gpio_byte0 = byte;
jah128 0:8a5497a2e366 204 //GPIO byte zero contains the power line traces and the switch states
jah128 0:8a5497a2e366 205 char current_switch = ((gpio_byte0 & 0xF8) >> 3);
jah128 0:8a5497a2e366 206 if(switch_set == 1) {
jah128 0:8a5497a2e366 207 if(current_switch != switch_byte) {
jah128 0:8a5497a2e366 208 previous_switch_byte = switch_byte;
jah128 0:8a5497a2e366 209 switch_byte = current_switch;
jah128 0:8a5497a2e366 210 event++;
jah128 0:8a5497a2e366 211 switch_event = 1;
jah128 0:8a5497a2e366 212 }
jah128 0:8a5497a2e366 213 } else {
jah128 0:8a5497a2e366 214 switch_byte = current_switch;
jah128 0:8a5497a2e366 215 switch_set = 1;
jah128 0:8a5497a2e366 216 }
jah128 0:8a5497a2e366 217 }
jah128 0:8a5497a2e366 218
jah128 0:8a5497a2e366 219 void IF_parse_gpio_byte1(char byte)
jah128 0:8a5497a2e366 220 {
jah128 0:8a5497a2e366 221 gpio_byte1 = byte;
jah128 0:8a5497a2e366 222 //GPIO byte one contains the wheel encoders and the ID switch
jah128 0:8a5497a2e366 223 char current_id = ((gpio_byte1 & 0xF0)>> 4);
jah128 0:8a5497a2e366 224 if(user_id_set == 1) {
jah128 0:8a5497a2e366 225 if(robot_id != current_id) {
jah128 0:8a5497a2e366 226 previous_robot_id = robot_id;
jah128 0:8a5497a2e366 227 robot_id = current_id;
jah128 0:8a5497a2e366 228 event++;
jah128 0:8a5497a2e366 229 change_id_event = 1;
jah128 0:8a5497a2e366 230 }
jah128 0:8a5497a2e366 231 } else {
jah128 0:8a5497a2e366 232 robot_id = current_id;
jah128 0:8a5497a2e366 233 user_id_set = 1;
jah128 0:8a5497a2e366 234 }
jah128 0:8a5497a2e366 235 char current_encoder = (gpio_byte1 & 0x0F);
jah128 0:8a5497a2e366 236 if(wheel_enc_set == 1) {
jah128 0:8a5497a2e366 237 if(wheel_encoder_byte != current_encoder) {
jah128 0:8a5497a2e366 238 previous_wheel_encoder_byte = wheel_encoder_byte;
jah128 0:8a5497a2e366 239 wheel_encoder_byte = current_encoder;
jah128 0:8a5497a2e366 240 event++;
jah128 0:8a5497a2e366 241 encoder_event = 1;
jah128 0:8a5497a2e366 242 }
jah128 0:8a5497a2e366 243 } else {
jah128 0:8a5497a2e366 244 wheel_encoder_byte = current_encoder;
jah128 0:8a5497a2e366 245 wheel_enc_set = 1;
jah128 0:8a5497a2e366 246 }
jah128 0:8a5497a2e366 247 }
jah128 0:8a5497a2e366 248
jah128 0:8a5497a2e366 249 void IF_handle_gpio_interrupt()
jah128 0:8a5497a2e366 250 {
jah128 0:8a5497a2e366 251 test = 1-test;
jah128 0:8a5497a2e366 252 test_led = test;
jah128 0:8a5497a2e366 253 IF_update_gpio_inputs();
jah128 0:8a5497a2e366 254 }
jah128 0:8a5497a2e366 255
jah128 0:8a5497a2e366 256 char IF_is_switch_pressed()
jah128 0:8a5497a2e366 257 {
jah128 0:8a5497a2e366 258 //Read data
jah128 0:8a5497a2e366 259 char data[1];
jah128 0:8a5497a2e366 260 char command[1] = {0}; //Command to read from input port 0
jah128 0:8a5497a2e366 261 primary_i2c.write(GPIO_IC_ADDRESS,command,1,false);
jah128 0:8a5497a2e366 262 primary_i2c.read(GPIO_IC_ADDRESS,data,1,false);
jah128 0:8a5497a2e366 263 return (data[0] & 0x80); //Returns a 1 if the center button is being pushed
jah128 0:8a5497a2e366 264 }
jah128 0:8a5497a2e366 265
jah128 0:8a5497a2e366 266
jah128 0:8a5497a2e366 267 char IF_get_switch_state()
jah128 0:8a5497a2e366 268 {
jah128 0:8a5497a2e366 269 //Read data
jah128 0:8a5497a2e366 270 char data[1];
jah128 0:8a5497a2e366 271 char command[1] = {0}; //Command to read from input port 0
jah128 0:8a5497a2e366 272 primary_i2c.write(GPIO_IC_ADDRESS,command,1,false);
jah128 0:8a5497a2e366 273 primary_i2c.read(GPIO_IC_ADDRESS,data,1,false);
jah128 0:8a5497a2e366 274 return (data[0] & 0xF8) >> 3; //Returns the current switch state
jah128 0:8a5497a2e366 275 }
jah128 0:8a5497a2e366 276
jah128 0:8a5497a2e366 277 void IF_update_gpio_inputs()
jah128 0:8a5497a2e366 278 {
jah128 0:8a5497a2e366 279 update_timeout.detach();
jah128 0:8a5497a2e366 280 //Read data
jah128 0:8a5497a2e366 281 char data[2];
jah128 0:8a5497a2e366 282 char command[1] = {0}; //Command to read from input port 0
jah128 0:8a5497a2e366 283 primary_i2c.write(GPIO_IC_ADDRESS,command,1,false);
jah128 0:8a5497a2e366 284 primary_i2c.read(GPIO_IC_ADDRESS,data,2,false);
jah128 0:8a5497a2e366 285 if(data[0]!=gpio_byte0) {
jah128 0:8a5497a2e366 286 IF_parse_gpio_byte0(data[0]);
jah128 0:8a5497a2e366 287 }
jah128 0:8a5497a2e366 288 if(data[1]!=gpio_byte1) {
jah128 0:8a5497a2e366 289 IF_parse_gpio_byte1(data[1]);
jah128 0:8a5497a2e366 290 }
jah128 0:8a5497a2e366 291 update_timeout.attach_us(&IF_update_gpio_inputs,50000);
jah128 0:8a5497a2e366 292 }
jah128 0:8a5497a2e366 293
jah128 0:8a5497a2e366 294
jah128 0:8a5497a2e366 295 void IF_write_to_led_ic(char byte_0, char byte_1)
jah128 0:8a5497a2e366 296 {
jah128 0:8a5497a2e366 297 //Set LEDs
jah128 0:8a5497a2e366 298 char data[3];
jah128 0:8a5497a2e366 299 data [0] = 0x02; //Write to output port
jah128 0:8a5497a2e366 300 data [1] = byte_0;
jah128 0:8a5497a2e366 301 data [2] = byte_1;
jah128 0:8a5497a2e366 302 primary_i2c.write(LED_IC_ADDRESS,data,3,false);
jah128 0:8a5497a2e366 303 }
jah128 0:8a5497a2e366 304
jah128 0:8a5497a2e366 305
jah128 0:8a5497a2e366 306 void IF_setup_temperature_sensor()
jah128 0:8a5497a2e366 307 {
jah128 0:8a5497a2e366 308 char data[3];
jah128 0:8a5497a2e366 309 data[0] = 0x04; //Set critical temp limit
jah128 0:8a5497a2e366 310 data[1] = TEMPERATURE_CRITICAL_HI;
jah128 0:8a5497a2e366 311 data[2] = TEMPEARTURE_CRITICAL_LO;
jah128 0:8a5497a2e366 312 primary_i2c.write(TEMPERATURE_ADDRESS,data,3,false);
jah128 0:8a5497a2e366 313 data[0] = 0x02; //Set high temp limit
jah128 0:8a5497a2e366 314 data[1] = TEMPERATURE_HIGH_HI;
jah128 0:8a5497a2e366 315 data[2] = TEMPEARTURE_HIGH_LO;
jah128 0:8a5497a2e366 316 primary_i2c.write(TEMPERATURE_ADDRESS,data,3,false);
jah128 0:8a5497a2e366 317 data[0] = 0x03; //Set low temp limit
jah128 0:8a5497a2e366 318 data[1] = TEMPERATURE_LOW_HI;
jah128 0:8a5497a2e366 319 data[2] = TEMPEARTURE_LOW_LO;
jah128 0:8a5497a2e366 320 primary_i2c.write(TEMPERATURE_ADDRESS,data,3,false);
jah128 0:8a5497a2e366 321 }
jah128 0:8a5497a2e366 322
jah128 0:8a5497a2e366 323 float IF_read_from_temperature_sensor()
jah128 0:8a5497a2e366 324 {
jah128 0:8a5497a2e366 325 char command[1] = {0x05}; //Write to Ta Register
jah128 0:8a5497a2e366 326 char data[3];
jah128 0:8a5497a2e366 327 signed int temp;
jah128 0:8a5497a2e366 328 float temperature;
jah128 0:8a5497a2e366 329 primary_i2c.write(TEMPERATURE_ADDRESS,command,1,false);
jah128 0:8a5497a2e366 330 primary_i2c.read(TEMPERATURE_ADDRESS,data,2,false);
jah128 0:8a5497a2e366 331
jah128 0:8a5497a2e366 332 //Convert the temperature data
jah128 0:8a5497a2e366 333 //First Check flag bits
jah128 0:8a5497a2e366 334 char UpperByte = data[0];
jah128 0:8a5497a2e366 335 char LowerByte = data[1];
jah128 0:8a5497a2e366 336 if ((UpperByte & 0x80) == 0x80) {
jah128 0:8a5497a2e366 337 debug("- WARNING: Temperature sensor reports critical temperature\n");
jah128 0:8a5497a2e366 338 }
jah128 0:8a5497a2e366 339 if ((UpperByte & 0x40) == 0x40) {
jah128 0:8a5497a2e366 340 debug("- WARNING: Temperature sensor reports above upper limit\n");
jah128 0:8a5497a2e366 341 }
jah128 0:8a5497a2e366 342 if ((UpperByte & 0x20) == 0x20) {
jah128 0:8a5497a2e366 343 debug("- WARNING: Temperature sensor reports below lower limit\n");
jah128 0:8a5497a2e366 344 }
jah128 0:8a5497a2e366 345 UpperByte = UpperByte & 0x1F; //Clear flag bits
jah128 0:8a5497a2e366 346 if ((UpperByte & 0x10) == 0x10) {
jah128 0:8a5497a2e366 347 UpperByte = UpperByte & 0x0F; //Clear SIGN
jah128 0:8a5497a2e366 348 temp = (UpperByte * 256) + LowerByte;
jah128 0:8a5497a2e366 349 temperature = - (temp / 16.0f);
jah128 0:8a5497a2e366 350 } else {
jah128 0:8a5497a2e366 351 temp = (UpperByte * 256) + LowerByte;
jah128 0:8a5497a2e366 352 temperature = (temp / 16.0f);
jah128 0:8a5497a2e366 353 }
jah128 0:8a5497a2e366 354 return temperature;
jah128 0:8a5497a2e366 355 }