Adding MCP3008 library

2 files changed, 93 insertions, 0 deletions

diff --git a/Adafruit_Python_MCP3008/Adafruit_MCP3008/MCP3008.py b/Adafruit_Python_MCP3008/Adafruit_MCP3008/MCP3008.py
new file mode 100644
index 0000000..027cec7
--- /dev/null
+++ b/Adafruit_Python_MCP3008/Adafruit_MCP3008/MCP3008.py
@@ -0,0 +1,92 @@
+# Copyright (c) 2016 Adafruit Industries
+# Author: Tony DiCola
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+import Adafruit_GPIO as GPIO
+import Adafruit_GPIO.SPI as SPI
+
+
+class MCP3008(object):
+    """Class to represent an Adafruit MCP3008 analog to digital converter.
+    """
+
+    def __init__(self, clk=None, cs=None, miso=None, mosi=None, spi=None, gpio=None):
+        """Initialize MAX31855 device with software SPI on the specified CLK,
+        CS, and DO pins.  Alternatively can specify hardware SPI by sending an
+        Adafruit_GPIO.SPI.SpiDev device in the spi parameter.
+        """
+        self._spi = None
+        # Handle hardware SPI
+        if spi is not None:
+            self._spi = spi
+        elif clk is not None and cs is not None and miso is not None and mosi is not None:
+            # Default to platform GPIO if not provided.
+            if gpio is None:
+                gpio = GPIO.get_platform_gpio()
+            self._spi = SPI.BitBang(gpio, clk, mosi, miso, cs)
+        else:
+            raise ValueError('Must specify either spi for for hardware SPI or clk, cs, miso, and mosi for softwrare SPI!')
+        self._spi.set_clock_hz(1000000)
+        self._spi.set_mode(0)
+        self._spi.set_bit_order(SPI.MSBFIRST)
+
+    def read_adc(self, adc_number):
+        """Read the current value of the specified ADC channel (0-7).  The values
+        can range from 0 to 1023 (10-bits).
+        """
+        assert 0 <= adc_number <= 7, 'ADC number must be a value of 0-7!'
+        # Build a single channel read command.
+        # For example channel zero = 0b11000000
+        command = 0b11 << 6                  # Start bit, single channel read
+        command |= (adc_number & 0x07) << 3  # Channel number (in 3 bits)
+        # Note the bottom 3 bits of command are 0, this is to account for the
+        # extra clock to do the conversion, and the low null bit returned at
+        # the start of the response.
+        resp = self._spi.transfer([command, 0x0, 0x0])
+        # Parse out the 10 bits of response data and return it.
+        result = (resp[0] & 0x01) << 9
+        result |= (resp[1] & 0xFF) << 1
+        result |= (resp[2] & 0x80) >> 7
+        return result & 0x3FF
+
+    def read_adc_difference(self, differential):
+        """Read the difference between two channels.  Differential should be a
+        value of:
+          - 0: Return channel 0 minus channel 1
+          - 1: Return channel 1 minus channel 0
+          - 2: Return channel 2 minus channel 3
+          - 3: Return channel 3 minus channel 2
+          - 4: Return channel 4 minus channel 5
+          - 5: Return channel 5 minus channel 4
+          - 6: Return channel 6 minus channel 7
+          - 7: Return channel 7 minus channel 6
+        """
+        assert 0 <= differential <= 7, 'Differential number must be a value of 0-7!'
+        # Build a difference channel read command.
+        command = 0b10 << 6                  # Start bit, differential read
+        command |= (differential & 0x07) << 3  # Channel number (in 3 bits)
+        # Note the bottom 3 bits of command are 0, this is to account for the
+        # extra clock to do the conversion, and the low null bit returned at
+        # the start of the response.
+        resp = self._spi.transfer([command, 0x0, 0x0])
+        # Parse out the 10 bits of response data and return it.
+        result = (resp[0] & 0x01) << 9
+        result |= (resp[1] & 0xFF) << 1
+        result |= (resp[2] & 0x80) >> 7
+        return result & 0x3FF
diff --git a/Adafruit_Python_MCP3008/Adafruit_MCP3008/__init__.py b/Adafruit_Python_MCP3008/Adafruit_MCP3008/__init__.py
new file mode 100644
index 0000000..767086c
--- /dev/null
+++ b/Adafruit_Python_MCP3008/Adafruit_MCP3008/__init__.py
@@ -0,0 +1 @@
+from .MCP3008 import MCP3008