Merge pull request adafruit#79 from boxysean/master

Bi-Color bargraph interface

Author: tdicola

Adafruit_LEDBackpack/Adafruit_Bargraph.py

@@ -0,0 +1,55 @@
+#!/usr/bin/python
+
+import time
+import datetime
+from Adafruit_LEDBackpack import LEDBackpack
+
+# ===========================================================================
+# Bargraph Display
+# ===========================================================================
+
+# This class is meant to be used with the 24-LED bicolor bargraph
+# displays available from Adafruit
+
+class Bargraph:
+  disp = None
+ 
+  LED_OFF = 0
+  LED_RED = 1
+  LED_GREEN = 2
+  LED_YELLOW = 3
+
+  # Constructor
+  def __init__(self, address=0x70, debug=False):
+    self.debug = debug
+
+    if self.debug:
+      print "Initializing a new instance of LEDBackpack at 0x%02X" % address
+    self.disp = LEDBackpack(address=address, debug=debug)
+
+  def setLed(self, bar, color):
+    if bar > 24:
+      return
+    if color > 3:
+      return
+
+    if bar < 12:
+      c = bar / 4
+    else:
+      c = (bar - 12) / 4
+
+    a = bar % 4;
+    if bar >= 12:
+      a += 4;
+    
+    if self.debug:
+      print "Ano = %d Cath %d" % (a, c)
+
+    bufRow = self.disp.getBufferRow(c) & ~((1 << a) | (1 << (a+8))) # turn off the LED
+
+    if color == self.LED_RED:
+      self.disp.setBufferRow(c, bufRow | (1 << a))
+    elif color == self.LED_YELLOW:
+      self.disp.setBufferRow(c, bufRow | (1 << a) | (1 << (a+8)))
+    elif color == self.LED_GREEN:
+      self.disp.setBufferRow(c, bufRow | 1 << (a+8))

Adafruit_LEDBackpack/Adafruit_LEDBackpack.py

@@ -64,6 +64,12 @@ def setBufferRow(self, row, value, update=True):
     if (update):
       self.writeDisplay()       # Update the display
 
+  def getBufferRow(self, row):
+    "Returns a single 16-bit entry in the 8*16-bit buffer"
+    if (row > 7):
+      return
+    return self.__buffer[row]
+
   def getBuffer(self):
     "Returns a copy of the raw buffer contents"
     bufferCopy = copy(self.__buffer)

Adafruit_LEDBackpack/ex_bargraph.py

@@ -0,0 +1,19 @@
+#!/usr/bin/python
+
+import time
+import datetime
+from Adafruit_Bargraph import Bargraph
+
+# ===========================================================================
+# Scroll through colors example
+# ===========================================================================
+bargraph = Bargraph(address=0x70)
+
+print "Press CTRL+C to exit"
+
+while(True):
+  for color in range(1, 4):
+    for i in range(24):
+      print i
+      bargraph.setLed(i, color)
+      time.sleep(0.05)