Revision 0:81c08f01f0fe, committed 2013-11-19

Comitter:

mazgch

Date:

Tue Nov 19 05:31:39 2013 +0000

Child:

1:2816fc874abc

Commit message:

draft;

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/INA219.cpp	Tue Nov 19 05:31:39 2013 +0000
@@ -0,0 +1,59 @@
+#include "INA219.h"
+
+INA219::INA219(PinName sda, PinName scl, unsigned char adr) :
+    _i2c(sda, scl)
+{
+    _i2c.frequency(100000);
+    _adr = adr;
+}
+
+bool INA219::detect(void)
+{
+    _i2c.start();
+    _adr = (1 == _i2c.write(_adr|1/*write address for reading*/));
+    _i2c.stop();
+    return _det;
+}
+
+double INA219::getCurrent(void)
+{
+    double d = 0.0;
+    if (_det)
+    {
+        char r = 0x01;
+        if (0 == _i2c.write(_adr, &r, sizeof(r), true))
+        {
+            char v[2] = {0};
+            if (0 == _i2c.read(_adr, v, sizeof(v)))
+            {
+                int u = (int)((((short)v[0]) << 8) + (unsigned char)v[1]) * 10; // uV
+                int i = u * 2/*0.5ohm*/;
+                d = 1e-6 * i;
+            }
+        }
+        else 
+            _i2c.stop();
+    }
+    return d;
+}
+
+double INA219::getVoltage(void)
+{
+    double d = 0.0;
+    if (_det)
+    {
+        char r = 0x02;
+        if (0 == _i2c.write(_adr, &r, sizeof(r), true))
+        {
+            char v[2] = {0};
+            if (0 == _i2c.read(_adr, v, sizeof(v)))
+            {
+                int u = (int)(((((short)v[0]) << 8) + (unsigned char)v[1]) >> 3) * 4; // mV
+                d = 1e-3 * u;
+            }
+        }
+        else 
+            _i2c.stop();
+    }
+    return d;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/INA219.h	Tue Nov 19 05:31:39 2013 +0000
@@ -0,0 +1,27 @@
+#include "mbed.h"
+
+
+/* Supply measurement chip (TI INA 219)
+   http://www.ti.com/product/ina219
+   
+   The INA219 is a high-side current shunt and power monitor 
+   with an I2C interface. The INA219 monitors both shunt drop
+   and supply voltage, with programmable conversion times and 
+   filtering. A programmable calibration value, combined with 
+   an internal multiplier, enables direct readouts in amperes. 
+   An additional multiplying register calculates power in watts. 
+   The I2C interface features 16 programmable addresse
+*/
+class INA219
+{
+public: 
+    INA219(PinName sda, PinName scl, 
+            unsigned char adr /* range 0x80(1000000)-0x9E(1001111) */);
+    bool detect(void);
+    double getCurrent(void);
+    double getVoltage(void);
+protected:
+    bool _det;
+    unsigned char _adr;
+    I2C _i2c;
+};
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