Diff: main.cpp

Revision:

0:80fb3c4621be

Child:

1:3baecb064743

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Tue Oct 23 19:39:34 2018 +0000
@@ -0,0 +1,79 @@
+#include "mbed.h"
+
+#define MCP9808_ADDR     (0x30) // MCP9808 base address 0x18<<1
+#define MCP9808_REG_TEMP (0x05) // Temperature Register
+#define MCP9808_REG_CONF (0x01) // Configuration Register
+#define MCP9808_REG_CRIT (0x04) // Critical Temperature Register
+
+
+LocalFileSystem local("local");               // Create the local filesystem under the name "local"
+// create an empty file pointer.
+FILE *myLogFile = NULL;
+
+Serial pc(USBTX, USBRX);
+I2C i2c(p9, p10);   // SDA, SCL on MCP9808
+// Note MCP9808 also needs VCC (3.3 V) and GND
+
+float TempValue;
+float data[20];
+char data_write[3], data_read[2];
+int ii, status;
+int main() {
+    char text[128];
+    pc.printf("Program will start when you enter a number\r\n");
+    pc.scanf("%s", text);
+    pc.printf("Printing all filenames:\r\n");
+    char fname[128];
+    DIR* dir = opendir("/local/");
+    struct dirent* de;
+    while((de = readdir(dir)) != NULL){
+        pc.printf("  %s\r\n", &(de->d_name)[0]);
+    }
+    // Wake up
+    data_write[0] = MCP9808_REG_CONF; // Register address
+    data_write[1] = 0x00;  // Data MSB, b11-15 not used, b9-10 =>T_HYS=0, b8 => continuous conversions
+    data_write[2] = 0x04;  // Data LSB,  Alert Off, Alert Disabled, Alert T>T_Crit, Alert active low, Alert interrupt
+    status = i2c.write(MCP9808_ADDR, data_write, 3, 0); // address,data,length,repeat
+    // address is chip addess
+    // First byte of data has register address 
+    // repeat true for multiple write when the chip autoincrements the address
+    // MCP9808 does not do this, so we leave it at 0
+      
+    while(1){
+        int i=0;
+        // this loops takes 10 data points and then
+        // appends those data points to a file
+        while(i<10){
+        // Read temperature  
+            data_write[0] = MCP9808_REG_TEMP;
+            i2c.write(MCP9808_ADDR, data_write, 1, 1); // no stop
+            i2c.read(MCP9808_ADDR, data_read, 2, 0);
+            status = data_read[0] >> 5;  // Shift flags to b0-b2
+            // 1 in flag means: T>T_crit(b2), T>T_Upper(b1), T<T_Lower(b0)
+           // pc.printf("the status is %n",status);
+            data_read[0] = data_read[0] & 0x1F;  // clear flag bits for temperature
+            
+            data[i] = (data_read[0] * 16) + (data_read[1] / 16.0); // combine two bytes
+            // Display the flags, if you wish
+            // pc.printf("Flags are %i \n\r",status);
+            // This displays to the user
+            pc.printf("%i Temperature is %3.1f\n\r",i,data[i]);
+            i=i+1;
+            wait(1);
+        }
+                
+        myLogFile = fopen("/local/log.txt", "a"); // open log.txt as a write only file (any existing file will be overwritten). Replace "w" with "a" to append
+        if (myLogFile == NULL) {  // check the file is open.
+            pc.printf("Couldn't open the log file.");
+            while (1) {
+                wait(10);
+            }
+        }
+        else{
+            for( ii = 0; ii < 10; ii++ ){
+                fprintf(myLogFile, "Index %i Temperature is %3.1f\r\n",ii,data[ii]);
+            }
+            fclose(myLogFile);
+        }
+    }
+}