Michael Ammann
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 addresses.
Diff: INA219.cpp
- Revision:
- 0:81c08f01f0fe
- Child:
- 1:2816fc874abc
diff -r 000000000000 -r 81c08f01f0fe INA219.cpp
--- /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;
+}