summaryrefslogtreecommitdiff
path: root/Adafruit_Python_MCP3008/Adafruit_MCP3008
diff options
context:
space:
mode:
Diffstat (limited to 'Adafruit_Python_MCP3008/Adafruit_MCP3008')
-rw-r--r--Adafruit_Python_MCP3008/Adafruit_MCP3008/MCP3008.py92
-rw-r--r--Adafruit_Python_MCP3008/Adafruit_MCP3008/__init__.py1
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