gpio Makefile changed to add PREFIX & DESTDIR

[wiringPi.git] / wiringPi / mcp3004.c

diff --git a/wiringPi/mcp3004.c b/wiringPi/mcp3004.c
index 1c9357f237a84b53e6e388df09e620ed627fd5df..82c73dd253165d306c8c2e81db108c11ccbcb53f 100644 (file)
--- a/wiringPi/mcp3004.c
+++ b/wiringPi/mcp3004.c
@@ -2,6 +2,8 @@
  * mcp3004.c:
  *     Extend wiringPi with the MCP3004 SPI Analog to Digital convertor
  *     Copyright (c) 2012-2013 Gordon Henderson
+ *
+ *     Thanks also to "ShorTie" on IRC for some remote debugging help!
  ***********************************************************************
  * This file is part of wiringPi:
  *     https://projects.drogon.net/raspberry-pi/wiringpi/
@@ -35,18 +37,19 @@
 
 static int myAnalogRead (struct wiringPiNodeStruct *node, int pin)
 {
-  unsigned char spiData [2] ;
+  unsigned char spiData [3] ;
   unsigned char chanBits ;
   int chan = pin - node->pinBase ;
 
-  chanBits = 0b11000000 | (chan << 3) ;
+  chanBits = 0b10000000 | (chan << 4) ;
 
-  spiData [0] = chanBits ;
-  spiData [1] = 0 ;
+  spiData [0] = 1 ;            // Start bit
+  spiData [1] = chanBits ;
+  spiData [2] = 0 ;
 
-  wiringPiSPIDataRW (node->fd, spiData, 2) ;
+  wiringPiSPIDataRW (node->fd, spiData, 3) ;
 
-  return ((spiData [0] << 7) | (spiData [1] >> 1)) & 0x3FF ;
+  return ((spiData [1] << 8) | spiData [2]) & 0x3FF ;
 }