Diff: MCP3425.cpp

Revision:

2:7375e645e806

Parent:

1:5ac344aa0aac

Child:

3:378672292488

--- a/MCP3425.cpp	Tue Apr 12 14:56:07 2016 +0000
+++ b/MCP3425.cpp	Wed Apr 13 14:45:11 2016 +0000
@@ -13,55 +13,103 @@
 #include "mbed.h"
 #include "MCP3425.h"
 
+const int MCP3425::ADDR = 0xD0;
 const float MCP3425::VREF = 2.048;
 
-MCP3425::MCP3425 (PinName sda, PinName scl) : _i2c(sda, scl) {
-    init();
+
+MCP3425::MCP3425(I2C& i2c)
+    :  _i2c(i2c), _addr(ADDR)
+{
+    _init();
 }
-MCP3425::MCP3425 (I2C& p_i2c) : _i2c(p_i2c) {
-    init();
+
+MCP3425::MCP3425(I2C& i2c, int addr)
+    : _i2c(i2c), _addr(addr)
+{
+    _init();
 }
 
+void MCP3425::set(MCP3425::Gain gain)
+{
+    _cfg.bit.G = (unsigned char)gain;
+    _write_cfg();
+}
+
+void MCP3425::set(MCP3425::Resolution resolution)
+{
+    _cfg.bit.S = (unsigned char)resolution;
+    _write_cfg();
+}
+
+void MCP3425::set(MCP3425::Conversion conversion)
+{
+    _cfg.bit.OC = (unsigned char)conversion;
+    _write_cfg();
+}
 
 short MCP3425::get()
 {
-    _i2c.read( MCP3425_ADDR, buf, 3);
-
-    ad.byte.HB=buf[0];
-    ad.byte.LB=buf[1];
-    config.UC=buf[2];
-    return ad.S;
+    return _get_code();
 }
 
 float MCP3425::read()
 {
+    short code = get();
+
     int gain = 1;
-    if (config.bit.G == 0) gain = 1;
-    else if (config.bit.G == 1) gain = 2;
-    else if (config.bit.G == 2) gain = 4;
-    else if (config.bit.G == 3) gain = 8;
+    if (_cfg.bit.G == 0) gain = 1;
+    else if (_cfg.bit.G == 1) gain = 2;
+    else if (_cfg.bit.G == 2) gain = 4;
+    else if (_cfg.bit.G == 3) gain = 8;
 
     int maxcode = 2047;
-    if (config.bit.S == 0 ) maxcode = 2047;
-    else if (config.bit.S == 1 ) maxcode = 8191;
-    else if (config.bit.S == 2 ) maxcode = 32767;
- 
-    short code = get();   
-    return code * VREF / gain / ( maxcode + 1 ); 
+    if (_cfg.bit.S == 0 ) maxcode = 2047;
+    else if (_cfg.bit.S == 1 ) maxcode = 8191;
+    else if (_cfg.bit.S == 2 ) maxcode = 32767;
+
+    return code * VREF / gain / ( maxcode + 1 );
+}
+
+void MCP3425::_init()
+{
+    _cfg.bit.G = (unsigned char)G1;
+    _cfg.bit.S = (unsigned char)W16;
+    _cfg.bit.OC = (unsigned char)ONESHOT;
+    _cfg.bit.C = 0;
+    _cfg.bit.RDY = 0;
+
+    _write_cfg();
 }
 
-
-void MCP3425::init()
+void MCP3425::_write_cfg()
 {
-
-    config.bit.RDY=1;
-    config.bit.C=0;
-    config.bit.OC=1;
-    config.bit.S=2;
-    config.bit.G=0;
-    // Initiate Continuous 16bits, 15SPS
-    buf[0]=config.UC;
-    _i2c.write(MCP3425_ADDR, buf, 1);
-
+    _buf[0] = _cfg.UC;
+    _i2c.write(_addr, _buf, 1);
 }
 
+short MCP3425::_get_code()
+{
+    // Trigger updating value if one-shot Mode
+    if (_cfg.bit.OC == 0)
+    {
+        _cfg.bit.RDY = 1;
+        _write_cfg();
+    }
+
+    while(1) {
+        if( _i2c.read( ADDR, _buf, 3) != 0 )
+        {
+            // failed to read (nack)
+            return 0;
+        }
+
+        _val.byte.HB = _buf[0];
+        _val.byte.LB = _buf[1];
+        _cfg.UC = _buf[2];
+        
+        if(_cfg.bit.RDY == 0 ) break;
+        wait_ms(5); // fastest rate: 240 SPS with 12-bit
+    }
+
+    return _val.S;
+}