Michael Chuah / MCP3208_Y

12bit 8ch ADC with SPI interface

Fork of MCP3208 by Yoji KURODA

Diff: mcp3208.cpp

Revision:
1:0876e83ba21b
Parent:
0:2300f3b42cdb
diff -r 2300f3b42cdb -r 0876e83ba21b mcp3208.cpp
--- a/mcp3208.cpp	Wed Oct 24 03:41:03 2012 +0000
+++ b/mcp3208.cpp	Wed Oct 24 05:52:21 2012 +0000
@@ -7,20 +7,19 @@
 MCP3208::MCP3208(PinName mosi, PinName miso, PinName clk, PinName cs)
 :   _spi(mosi,miso,clk),
     _cs(cs),
-    vref(5.0)
+    _vref(5.0)
 {
     _spi.frequency(2000000);
-    _spi.format(14,3);
-    _cs = 1;    
+    _spi.format(12,3);
+    _cs = 1;
 }
 
 int
 MCP3208::binary(int ch)
 {
     _cs = 0;
-    int ret = _spi.write(0x18|ch);
+    int ret = _spi.write((0x18|ch)<<2);
     int adb = _spi.write(0);
-    int dum = _spi.write(0);
     _cs = 1;
     return adb;
 }
@@ -28,6 +27,6 @@
 float
 MCP3208::volt(int ch)
 {
-    return vref * binary(ch) / 4095;
+    return _vref * binary(ch) / 4095;
 }