Sam Berjawi / ADS1015

A library for ADS1015 and ADS1115 from Texas Instruments.

Fork of ADS1015 by Arve Seljebu

v1.3 - Added ADS1115_REG_CONFIG_DR & m_dataRate Jul 21. 2014 - Corrected m_conversionDelay - Now there is readADC() that returns counts and readADC_V() that returns voltage

Diff: Adafruit_ADS1015.cpp

Revision:
1:a628fdaed351
Parent:
0:8174d9ceeca1
--- a/Adafruit_ADS1015.cpp	Sun Nov 10 18:22:27 2013 +0000
+++ b/Adafruit_ADS1015.cpp	Wed May 21 13:12:24 2014 +0000
@@ -17,8 +17,10 @@
 
     @section  HISTORY
 
-    v1.0 - First release
-    v1.1.1 - Ported to mbed
+    v1.0   - First release
+    v1.1   - Added ADS1115 support - W. Earl
+    v1.1.1 - Ported to mbed - Arve Seljebu
+    v1.2   - Fixed error in readADC_SingleEnded() sign bit - Sam Berjawi
 */
 /**************************************************************************/
 
@@ -106,7 +108,8 @@
     @brief  Gets a single-ended ADC reading from the specified channel
 */
 /**************************************************************************/
-uint16_t Adafruit_ADS1015::readADC_SingleEnded(uint8_t channel) {
+//uint16_t Adafruit_ADS1015::readADC_SingleEnded(uint8_t channel) { SWB
+int16_t Adafruit_ADS1015::readADC_SingleEnded(uint8_t channel) {
   if (channel > 3)
   {
     return 0;
@@ -151,7 +154,27 @@
 
   // Read the conversion results
   // Shift 12-bit results right 4 bits for the ADS1015
-  return readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;  
+  //return readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;  SWB
+
+  // SWB
+  // Shift 12-bit results right 4 bits for the ADS1015
+  uint16_t res = readRegister(m_i2cAddress, ADS1015_REG_POINTER_CONVERT) >> m_bitShift;
+
+  if (m_bitShift == 0)
+  {
+    return (int16_t)res;
+  }
+  else
+  {
+    // Shift 12-bit results right 4 bits for the ADS1015,
+    // making sure we keep the sign bit intact
+    if (res > 0x07FF)
+    {
+      // negative number - extend the sign to 16th bit
+      res |= 0xF000;
+    }
+    return (int16_t)res;
+  }
 }
 
 /**************************************************************************/