Added I2C block write

Author: K. Townsend

Adafruit_I2C/Adafruit_I2C.py

@@ -34,11 +34,11 @@ def write8(self, reg, value):
     except IOError, err:
       print "Error accessing 0x%02X: Check your I2C address" % self.address
       return -1
-      
-  def write16(self, reg, value):
-    "Writes 16 bits of data to the specified register/address"
+
+  def writeList(self, reg, list):
+    "Writes an array of bytes using I2C format"
     try:
-      self.bus.write_word_data(self.address, reg, value)
+      self.bus.write_i2c_block_data(self.address, reg, list)
     except IOError, err:
       print "Error accessing 0x%02X: Check your I2C address" % self.address
       return -1

Adafruit_MCP4725/Adafruit_MCP4725.py

@@ -23,16 +23,13 @@ def setVoltage(self, voltage, persist=False):
     "Sets the output voltage to the specified value"
     if (voltage > 4095):
       voltage = 4095
+    if (voltage < 0):
+      voltage = 0
     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))
+    bytes = [(voltage >> 4) & 0xFF, (voltage << 4) & 0xFF]
+    if (persist):
+      self.i2c.writeList(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)
+      self.i2c.writeList(self.__REG_WRITEDAC, bytes)

Adafruit_MCP4725/sinewave.py

@@ -0,0 +1,175 @@
+#!/usr/bin/python
+
+from Adafruit_MCP4725 import MCP4725
+import time
+
+# Set this value to 9, 8, 7, 6 or 5 to adjust the resolution
+DAC_RESOLUTION    = 9
+
+# 9-Bit Lookup Table (512 values)
+DACLookup_FullSine_9Bit = \
+[ 2048, 2073, 2098, 2123, 2148, 2174, 2199, 2224,
+  2249, 2274, 2299, 2324, 2349, 2373, 2398, 2423,
+  2448, 2472, 2497, 2521, 2546, 2570, 2594, 2618,
+  2643, 2667, 2690, 2714, 2738, 2762, 2785, 2808,
+  2832, 2855, 2878, 2901, 2924, 2946, 2969, 2991,
+  3013, 3036, 3057, 3079, 3101, 3122, 3144, 3165,
+  3186, 3207, 3227, 3248, 3268, 3288, 3308, 3328,
+  3347, 3367, 3386, 3405, 3423, 3442, 3460, 3478,
+  3496, 3514, 3531, 3548, 3565, 3582, 3599, 3615,
+  3631, 3647, 3663, 3678, 3693, 3708, 3722, 3737,
+  3751, 3765, 3778, 3792, 3805, 3817, 3830, 3842,
+  3854, 3866, 3877, 3888, 3899, 3910, 3920, 3930,
+  3940, 3950, 3959, 3968, 3976, 3985, 3993, 4000,
+  4008, 4015, 4022, 4028, 4035, 4041, 4046, 4052,
+  4057, 4061, 4066, 4070, 4074, 4077, 4081, 4084,
+  4086, 4088, 4090, 4092, 4094, 4095, 4095, 4095,
+  4095, 4095, 4095, 4095, 4094, 4092, 4090, 4088,
+  4086, 4084, 4081, 4077, 4074, 4070, 4066, 4061,
+  4057, 4052, 4046, 4041, 4035, 4028, 4022, 4015,
+  4008, 4000, 3993, 3985, 3976, 3968, 3959, 3950,
+  3940, 3930, 3920, 3910, 3899, 3888, 3877, 3866,
+  3854, 3842, 3830, 3817, 3805, 3792, 3778, 3765,
+  3751, 3737, 3722, 3708, 3693, 3678, 3663, 3647,
+  3631, 3615, 3599, 3582, 3565, 3548, 3531, 3514,
+  3496, 3478, 3460, 3442, 3423, 3405, 3386, 3367,
+  3347, 3328, 3308, 3288, 3268, 3248, 3227, 3207,
+  3186, 3165, 3144, 3122, 3101, 3079, 3057, 3036,
+  3013, 2991, 2969, 2946, 2924, 2901, 2878, 2855,
+  2832, 2808, 2785, 2762, 2738, 2714, 2690, 2667,
+  2643, 2618, 2594, 2570, 2546, 2521, 2497, 2472,
+  2448, 2423, 2398, 2373, 2349, 2324, 2299, 2274,
+  2249, 2224, 2199, 2174, 2148, 2123, 2098, 2073,
+  2048, 2023, 1998, 1973, 1948, 1922, 1897, 1872,
+  1847, 1822, 1797, 1772, 1747, 1723, 1698, 1673,
+  1648, 1624, 1599, 1575, 1550, 1526, 1502, 1478,
+  1453, 1429, 1406, 1382, 1358, 1334, 1311, 1288,
+  1264, 1241, 1218, 1195, 1172, 1150, 1127, 1105,
+  1083, 1060, 1039, 1017,  995,  974,  952,  931,
+   910,  889,  869,  848,  828,  808,  788,  768,
+   749,  729,  710,  691,  673,  654,  636,  618,
+   600,  582,  565,  548,  531,  514,  497,  481,
+   465,  449,  433,  418,  403,  388,  374,  359,
+   345,  331,  318,  304,  291,  279,  266,  254,
+   242,  230,  219,  208,  197,  186,  176,  166,
+   156,  146,  137,  128,  120,  111,  103,   96,
+    88,   81,   74,   68,   61,   55,   50,   44,
+    39,   35,   30,   26,   22,   19,   15,   12,
+    10,    8,    6,    4,    2,    1,    1,    0,
+     0,    0,    1,    1,    2,    4,    6,    8,
+    10,   12,   15,   19,   22,   26,   30,   35,
+#    16,   16,   16,   16,   16,   16,   16,   16,
+#    16,   16,   16,   16,   16,   16,   16,   16,
+#    16,   16,   16,   16,   16,   16,   16,   16,
+    39,   44,   50,   55,   61,   68,   74,   81,
+    88,   96,  103,  111,  120,  128,  137,  146,
+   156,  166,  176,  186,  197,  208,  219,  230,
+   242,  254,  266,  279,  291,  304,  318,  331,
+   345,  359,  374,  388,  403,  418,  433,  449,
+   465,  481,  497,  514,  531,  548,  565,  582,
+   600,  618,  636,  654,  673,  691,  710,  729,
+   749,  768,  788,  808,  828,  848,  869,  889,
+   910,  931,  952,  974,  995, 1017, 1039, 1060,
+  1083, 1105, 1127, 1150, 1172, 1195, 1218, 1241,
+  1264, 1288, 1311, 1334, 1358, 1382, 1406, 1429,
+  1453, 1478, 1502, 1526, 1550, 1575, 1599, 1624,
+  1648, 1673, 1698, 1723, 1747, 1772, 1797, 1822,
+  1847, 1872, 1897, 1922, 1948, 1973, 1998, 2023 ]
+
+# 8-bit Lookup Table (256 values)
+DACLookup_FullSine_8Bit = \
+[ 2048, 2098, 2148, 2198, 2248, 2298, 2348, 2398,
+  2447, 2496, 2545, 2594, 2642, 2690, 2737, 2784,
+  2831, 2877, 2923, 2968, 3013, 3057, 3100, 3143,
+  3185, 3226, 3267, 3307, 3346, 3385, 3423, 3459,
+  3495, 3530, 3565, 3598, 3630, 3662, 3692, 3722,
+  3750, 3777, 3804, 3829, 3853, 3876, 3898, 3919,
+  3939, 3958, 3975, 3992, 4007, 4021, 4034, 4045,
+  4056, 4065, 4073, 4080, 4085, 4089, 4093, 4094,
+  4095, 4094, 4093, 4089, 4085, 4080, 4073, 4065,
+  4056, 4045, 4034, 4021, 4007, 3992, 3975, 3958,
+  3939, 3919, 3898, 3876, 3853, 3829, 3804, 3777,
+  3750, 3722, 3692, 3662, 3630, 3598, 3565, 3530,
+  3495, 3459, 3423, 3385, 3346, 3307, 3267, 3226,
+  3185, 3143, 3100, 3057, 3013, 2968, 2923, 2877,
+  2831, 2784, 2737, 2690, 2642, 2594, 2545, 2496,
+  2447, 2398, 2348, 2298, 2248, 2198, 2148, 2098,
+  2048, 1997, 1947, 1897, 1847, 1797, 1747, 1697,
+  1648, 1599, 1550, 1501, 1453, 1405, 1358, 1311,
+  1264, 1218, 1172, 1127, 1082, 1038,  995,  952,
+   910,  869,  828,  788,  749,  710,  672,  636,
+   600,  565,  530,  497,  465,  433,  403,  373,
+   345,  318,  291,  266,  242,  219,  197,  176,
+   156,  137,  120,  103,   88,   74,   61,   50,
+    39,   30,   22,   15,   10,    6,    2,    1,
+     0,    1,    2,    6,   10,   15,   22,   30,
+    39,   50,   61,   74,   88,  103,  120,  137,
+   156,  176,  197,  219,  242,  266,  291,  318,
+   345,  373,  403,  433,  465,  497,  530,  565,
+   600,  636,  672,  710,  749,  788,  828,  869,
+   910,  952,  995, 1038, 1082, 1127, 1172, 1218,
+  1264, 1311, 1358, 1405, 1453, 1501, 1550, 1599,
+  1648, 1697, 1747, 1797, 1847, 1897, 1947, 1997 ]
+
+# 7-bit Lookup Table (128 values)
+DACLookup_FullSine_7Bit = \
+[ 2048, 2148, 2248, 2348, 2447, 2545, 2642, 2737,
+  2831, 2923, 3013, 3100, 3185, 3267, 3346, 3423,
+  3495, 3565, 3630, 3692, 3750, 3804, 3853, 3898,
+  3939, 3975, 4007, 4034, 4056, 4073, 4085, 4093,
+  4095, 4093, 4085, 4073, 4056, 4034, 4007, 3975,
+  3939, 3898, 3853, 3804, 3750, 3692, 3630, 3565,
+  3495, 3423, 3346, 3267, 3185, 3100, 3013, 2923,
+  2831, 2737, 2642, 2545, 2447, 2348, 2248, 2148,
+  2048, 1947, 1847, 1747, 1648, 1550, 1453, 1358,
+  1264, 1172, 1082,  995,  910,  828,  749,  672,
+   600,  530,  465,  403,  345,  291,  242,  197,
+   156,  120,   88,   61,   39,   22,   10,    2,
+     0,    2,   10,   22,   39,   61,   88,  120,
+   156,  197,  242,  291,  345,  403,  465,  530,
+   600,  672,  749,  828,  910,  995, 1082, 1172,
+  1264, 1358, 1453, 1550, 1648, 1747, 1847, 1947 ]
+
+# 6-bit Lookup Table (64 values)
+DACLookup_FullSine_6Bit = \
+[ 2048, 2248, 2447, 2642, 2831, 3013, 3185, 3346,
+  3495, 3630, 3750, 3853, 3939, 4007, 4056, 4085,
+  4095, 4085, 4056, 4007, 3939, 3853, 3750, 3630,
+  3495, 3346, 3185, 3013, 2831, 2642, 2447, 2248,
+  2048, 1847, 1648, 1453, 1264, 1082,  910,  749,
+   600,  465,  345,  242,  156,   88,   39,   10,
+     0,   10,   39,   88,  156,  242,  345,  465,
+   600,  749,  910, 1082, 1264, 1453, 1648, 1847 ]
+
+# 5-bit Lookup Table (32 values)
+DACLookup_FullSine_5Bit = \
+[ 2048, 2447, 2831, 3185, 3495, 3750, 3939, 4056,
+  4095, 4056, 3939, 3750, 3495, 3185, 2831, 2447,
+  2048, 1648, 1264,  910,  600,  345,  156,   39,
+     0,   39,  156,  345,  600,  910, 1264, 1648 ]
+
+# Initialise the DAC using the default address
+dac = MCP4725(0x62)
+
+if (DAC_RESOLUTION < 5) | (DAC_RESOLUTION > 9):
+  print "Invalid DAC resolution: Set DAC_RESOLUTION from 5..9"
+else:
+  print "Generating a sine wave with %d-bit resolution" % DAC_RESOLUTION
+  print "Press CTRL+C to stop"
+  while(True):
+    if (DAC_RESOLUTION == 9):
+      for val in DACLookup_FullSine_9Bit:
+        dac.setVoltage(val)
+    if (DAC_RESOLUTION == 8):
+      for val in DACLookup_FullSine_8Bit:
+        dac.setVoltage(val)
+    if (DAC_RESOLUTION == 7):
+       for val in DACLookup_FullSine_7Bit:
+        dac.setVoltage(val)
+    if (DAC_RESOLUTION == 6):
+      for val in DACLookup_FullSine_6Bit:
+        dac.setVoltage(val)
+    if (DAC_RESOLUTION == 5):
+      for val in DACLookup_FullSine_5Bit:
+        dac.setVoltage(val)
+