LM75B I2C temperature sensor

Dependencies:   mbed

Revision:
0:00a546855093
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LM75B.cpp	Wed Feb 04 05:47:22 2015 +0000
@@ -0,0 +1,78 @@
+#include "mbed.h"
+#include "stdint.h"
+#include "LM75B.h"
+ 
+I2C i2c(p28,p27);        // sda, scl
+Serial pc(USBTX, USBRX); // tx, rx
+char cmd[32];
+int i;
+short T;
+
+void set_ch(char sel)
+{    // PCA9541のサンプル
+        // MST_0側の自分にスレーブ側の制御権を得る場合
+    cmd[0] = 1;                     // PCA9541 コマンドコード Cont Reg
+    i2c.write( 0xe2, cmd, 1);       // Cont Regを指定
+    i2c.read( 0xe2, cmd, 1);        // Cont Regを読込み
+    wait(0.1);                      // 0.1s待つ
+    switch(cmd[0] & 0xf)
+    {
+    case 0:                         // bus off, has control
+    case 1:                         // bus off, no control
+    case 5:                         // bus on, no control
+        cmd[0] = 1;                 // PCA9541 コマンドコード Cont Reg
+        cmd[1] = 4;                 // bus on, has control
+        i2c.write( 0xe2, cmd, 2);   // Cont Regにcmd[1]を書込み
+        i2c.read( 0xe2, cmd, 1);    // Cont Regを読込み
+        break;
+    case 2:                         // bus off, no control
+    case 3:                         // bus off, has control
+    case 6:                         // bus on, no control
+        cmd[0] = 1;                 // PCA9541 コマンドコード Cont Reg
+        cmd[1] = 5;                 // bus on, has control
+        i2c.write( 0xe2, cmd, 2);   // Cont Regにcmd[1]を書込み
+        i2c.read( 0xe2, cmd, 1);    // Cont Regを読込み
+        break;
+    case 9:                         // bus on, no control
+    case 0xc:                       // bus on, no control
+    case 0xd:                       // bus off, no control
+        cmd[0] = 1;                 // PCA9541 コマンドコード Cont Reg
+        cmd[1] = 0;                 // bus on, has control
+        i2c.write( 0xe2, cmd, 2);   // Cont Regにcmd[1]を書込み
+        i2c.read( 0xe2, cmd, 1);    // Cont Regを読込み
+        break;
+    case 0xa:                       // bus on, no control
+    case 0xe:                       // bus off, no control
+    case 0xf:                       // bus on, has control
+        cmd[0] = 1;                 // PCA9541 コマンドコード Cont Reg
+        cmd[1] = 1;                 // bus on, has control
+        i2c.write( 0xe2, cmd, 2);   // Cont Regにcmd[1]を書込み
+        i2c.read( 0xe2, cmd, 1);    // Cont Regを読込み
+        break;
+    default:
+        break;
+    }
+
+    cmd[0] = sel;                   // PCA9546 Cont Reg sel channel enabled
+    i2c.write( 0xe8, cmd, 1);       // Send command string
+}
+  
+int main ()
+{
+    i2c.frequency(100000);
+    pc.printf("LM75B Sample Program\r\n");
+    set_ch(2);              // LM75Bはch1に接続
+
+  // LM75B
+    while(1)
+    {
+        cmd[0] = Temp;
+        i2c.write(LM75_ADDR, cmd, 1, true); // pointer = Temp
+        i2c.read(LM75_ADDR, cmd, 2);        // Read Temp register
+        T = (cmd[0]<<8) | cmd[1];           // calculate temperature
+        pc.printf("%.2f ℃\r\n", T / 256.0);
+        wait(2.0);
+    }
+}
+ 
+