First commit

Author: K. Townsend

Adafruit_MCP4725/Adafruit_MCP4725.py

@@ -0,0 +1,38 @@
+#!/usr/bin/python
+
+from Adafruit_I2C import Adafruit_I2C
+
+# ============================================================================
+# Adafruit MCP4725 12-Bit DAC
+# ============================================================================
+
+class MCP4725 :
+  i2c = None
+  
+  # Registers
+  __REG_WRITEDAC         = 0x40
+  __REG_WRITEDACEEPROM   = 0x60
+
+  # Constructor
+  def __init__(self, address=0x62, debug=False):
+    self.i2c = Adafruit_I2C(address)
+    self.address = address
+    self.debug = debug
+
+  def setVoltage(self, voltage, persist=False):
+    "Sets the output voltage to the specified value"
+    if (voltage > 4095):
+      voltage = 4095
+    if (self.debug):
+      print "Setting voltage to %04d" % voltage
+    # Value needs to be left-shifted four bytes for the MCP4725
+    voltage <<= 4
+    if (persist==True):
+      self.i2c.write16(self.__REG_WRITEDACEEPROM, self.i2c.reverseByteOrder(voltage))
+    else:
+      self.i2c.write16(self.__REG_WRITEDAC, self.i2c.reverseByteOrder(voltage))
+
+# Initialise a new instance of MCP4725 using the default address (0x62)
+dac = MCP4725(0x62)
+# Set output voltage to 50% VCC
+dac.setVoltage(2048)