Merge pull request #13 from yoomy3/fix-MCP3008-differential

Fix mcp3008 differential

Author: brentru

adafruit_mcp3xxx/mcp3004.py

@@ -39,7 +39,11 @@
 class MCP3004(MCP3xxx):
 
     """
-    MCP3004 Diff. Channel Mapping.
+    MCP3004 Differential channel mapping.
+        - 0: CH0 = IN+, CH1 = IN-
+        - 1: CH1 = IN+, CH0 = IN-
+        - 2: CH2 = IN+, CH3 = IN-
+        - 3: CH3 = IN+, CH2 = IN-
     """
     MCP3004_DIFF_PINS = {
         (0, 1) : P0,

adafruit_mcp3xxx/mcp3008.py

@@ -43,7 +43,15 @@
 class MCP3008(MCP3xxx):
 
     """
-    MCP3008 Diff. Channel Mapping.
+    MCP3008 Differential channel mapping.
+        - 0: CH0 = IN+, CH1 = IN-
+        - 1: CH1 = IN+, CH0 = IN-
+        - 2: CH2 = IN+, CH3 = IN-
+        - 3: CH3 = IN+, CH2 = IN-
+        - 4: CH4 = IN+, CH5 = IN-
+        - 5: CH5 = IN+, CH4 = IN-
+        - 6: CH6 = IN+, CH7 = IN-
+        - 7: CH7 = IN+, CH6 = IN-
     """
     MCP3008_DIFF_PINS = {
         (0, 1) : P0,
@@ -53,5 +61,5 @@ class MCP3008(MCP3xxx):
         (4, 5) : P4,
         (5, 4) : P5,
         (6, 7) : P6,
-        (6, 6) : P7
+        (7, 6) : P7
     }