Diff: main.cpp

Revision:

97:654993254328

Parent:

88:bea4f2daa48c

--- a/main.cpp	Fri May 31 13:00:04 2019 +0100
+++ b/main.cpp	Tue Jun 25 18:27:32 2019 +0000
@@ -1,32 +1,104 @@
-/* mbed Microcontroller Library
- * Copyright (c) 2018 ARM Limited
- * SPDX-License-Identifier: Apache-2.0
- */
+/*The following program is intended for reading the MAX31723 Temperature Sensor
+via SPI connections. The program was evaluated using a MAX32600MBED board, with
+temperature values being displayed via USB connection to a serial monitor. Both Celsius
+and Fahrenheit are supported and displayed. 
+
+By default, the sensor is placed into Sleep-Mode, and temperature samples are only
+collected after a One-Shot Configuration is sent to the Configuration Register.
+There is a pause for the maximum sampling time before the new temperature values are
+read. The Configuration register is set to the highest precision mode, requiring 4 bits
+stored in the LSB Register. */
+
+#include "mbed.h"              
+
+Serial pc(USBTX, USBRX);
+SPI spi(P2_1,P2_2,P2_0);        //Mosi, Miso, sck
+DigitalOut cs(P2_5);        //Define enable pin
+
+/*Define Constant address variables for reading and writing to
+temperature sensor registers. All values can be found on MAX31723
+data sheet and are labled below */
 
-#include "mbed.h"
-#include "stats_report.h"
+const uint8_t Garbage = 0xff;
+const uint8_t Configuration_Write_Address = 0x80;
+const uint8_t Configuration_Read_Address = 0x00;
+const uint8_t Temperature_Read_Address_LSB = 0x01;
+const uint8_t Temperature_Read_Address_MSB = 0x02;
+const uint8_t Configuration_Sleep = 0x80;
+const uint8_t Configuration_OneShot = 0x10;
+
+int data, data2, config;
+char bdata[7];
 
-DigitalOut led1(LED1);
+int main(){
+    
+    pc.printf("=================  STARTING  =================\r\n");    
+    spi.format(8,3);        //Read 8 bit burst, mode 3
+    spi.frequency(10000);       //Set frequency to 10000Hz 
+    cs=0;       //Set enable to 0
+    
+    wait_ms(500);
+    
+    while(1){
 
-#define SLEEP_TIME                  500 // (msec)
-#define PRINT_AFTER_N_LOOPS         20
+        /*Send Oneshot signal with highest percision bit setting */
 
-// main() runs in its own thread in the OS
-int main()
-{
-    SystemReport sys_state( SLEEP_TIME * PRINT_AFTER_N_LOOPS /* Loop delay time in ms */);
+        cs=1;
+        spi.write(Configuration_Write_Address);
+        spi.write(0x17);      
+        cs=0;
+        
+        wait_ms(200);           //Wait maximum time for temperature capture
+        
+        /*Read temperature register holding LSB*/
+        
+        cs=1;
+        spi.write(Temperature_Read_Address_LSB);
+        data = spi.write(0xff);
+        cs=0;
 
-    int count = 0;
-    while (true) {
-        // Blink LED and wait 0.5 seconds
-        led1 = !led1;
-        wait_ms(SLEEP_TIME);
-
-        if ((0 == count) || (PRINT_AFTER_N_LOOPS == count)) {
-            // Following the main thread wait, report on the current system status
-            sys_state.report_state();
-            count = 0;
+        /*Converts the decimal number held in "data" into a binary array*/
+        
+        int count = 7;
+        for (int j = 7;j>=0;j--){
+                int r = data>>j;
+                if(r&1)
+                     bdata[count] = 1;
+                else
+                     bdata[count] = 0;
+                count --;
+            }
+        
+        /*Read temperature register holding MSB*/
+        
+        cs=1;
+        spi.write(Temperature_Read_Address_MSB);
+        data2 = spi.write(Garbage);
+        cs=0;
+        
+        
+        /*Function for calculating temperature based on bit values stored
+        in temperature registers, All equations and values found on MAX31723
+        data sheet under "Measuring Temperature" section header.  */
+        
+        double temp = data2;        //Temperature MSB is already converted to Decimal
+        int index = 7;
+        for (float z=-1;z>=-4;z--){         //Calculate temperature from array holding binary value
+            float factor = pow (2,z);       //Calculate Added Temperature for each bit (Per data sheet)
+            temp += bdata[index] * factor;      //Combine all bit temperature to aquire total sum
+            index--;
         }
-        ++count;
+        
+        /*Calculate temperature in F using equation F(deg) = (5/9) * C(deg) + 32 */
+        
+        float fahrenheit = (((temp*9)/5) + 32);     
+        
+        /*Print out Results*/
+        
+        pc.printf("Temperature is %f degrees Celcius\r\n", temp);
+        pc.printf("Temperature is %f degrees Fahrenheit\r\n", fahrenheit);
+        pc.printf("Reading Complete\r\n");
+        pc.printf("\r\n\n\n\n\n");
+        wait(2);
     }
-}
+}
\ No newline at end of file