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‎ADS1115/I2C.py

Lines changed: 147 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,147 @@
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# ===========================================================================
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# Adafruit_I2C Class
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# ===========================================================================
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import time
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import smbus
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class Adafruit_I2C(object):
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@staticmethod
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def getPiRevision():
11+
"Gets the version number of the Raspberry Pi board"
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# Revision list available at: http://elinux.org/RPi_HardwareHistory#Board_Revision_History
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try:
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with open('/proc/cpuinfo', 'r') as infile:
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for line in infile:
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# Match a line of the form "Revision : 0002" while ignoring extra
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# info in front of the revsion (like 1000 when the Pi was over-volted).
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match = re.match('Revision\s+:\s+.*(\w{4})$', line)
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if match and match.group(1) in ['0000', '0002', '0003']:
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# Return revision 1 if revision ends with 0000, 0002 or 0003.
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return 1
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elif match:
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# Assume revision 2 if revision ends with any other 4 chars.
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return 2
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# Couldn't find the revision, assume revision 0 like older code for compatibility.
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return 0
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except:
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return 0
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@staticmethod
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def getPiI2CBusNumber():
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# Gets the I2C bus number /dev/i2c#
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return 1 if Adafruit_I2C.getPiRevision() > 1 else 0
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def __init__(self, address, busnum=-1, debug=False):
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self.address = address
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# By default, the correct I2C bus is auto-detected using /proc/cpuinfo
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# Alternatively, you can hard-code the bus version below:
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# self.bus = smbus.SMBus(0); # Force I2C0 (early 256MB Pi's)
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# self.bus = smbus.SMBus(1); # Force I2C1 (512MB Pi's)
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self.bus = smbus.SMBus(busnum if busnum >= 0 else Adafruit_I2C.getPiI2CBusNumber())
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self.debug = debug
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def reverseByteOrder(self, data):
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''' Reverses the byte order of an int (16-bit) or long (32-bit) value '''
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byteCount = len(hex(data)[2:].replace('L','')[::2])
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val = 0
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for i in range(byteCount):
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val = (val << 8) | (data & 0xff)
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data >>= 8
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return val
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def errMsg(self):
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print ("Error accessing 0x%02X: Check your I2C address" % self.address)
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return -1
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def write8(self, reg, value):
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"Writes an 8-bit value to the specified register/address"
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try:
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self.bus.write_byte_data(self.address, reg, value)
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if self.debug:
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print ("I2C: Wrote 0x%02X to register 0x%02X" % (value, reg))
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except IOError:
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return self.errMsg()
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def write16(self, reg, value):
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"Writes a 16-bit value to the specified register/address pair"
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try:
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self.bus.write_word_data(self.address, reg, value)
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if self.debug:
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print ("I2C: Wrote 0x%02X to register pair 0x%02X,0x%02X" % (value, reg, reg+1))
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except IOError:
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return self.errMsg()
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def writeRaw8(self, value):
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"Writes an 8-bit value on the bus"
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try:
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self.bus.write_byte(self.address, value)
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if self.debug:
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print ("I2C: Wrote 0x%02X" % value)
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except IOError:
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return self.errMsg()
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def writeList(self, reg, list):
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"Writes an array of bytes using I2C format"
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try:
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if self.debug:
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print ("I2C: Writing list to register 0x%02X:" % reg)
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print (list)
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self.bus.write_i2c_block_data(self.address, reg, list)
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except IOError:
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return self.errMsg()
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def readList(self, reg, length):
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"Read a list of bytes from the I2C device"
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try:
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results = self.bus.read_i2c_block_data(self.address, reg, length)
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if self.debug:
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print ("I2C: Device 0x%02X returned the following from reg 0x%02X" % (self.address, reg))
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print (results)
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return results
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except IOError:
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return self.errMsg()
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def readU8(self, reg):
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"Read an unsigned byte from the I2C device"
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try:
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result = self.bus.read_byte_data(self.address, reg)
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if self.debug:
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print ("I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" % (self.address, result & 0xFF, reg))
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return (result)
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except IOError:
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return self.errMsg()
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115+
def readS8(self, reg):
116+
"Reads a signed byte from the I2C device"
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try:
118+
result = self.bus.read_byte_data(self.address, reg)
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if result > 127: result -= 256
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if self.debug:
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print ("I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" % (self.address, result & 0xFF, reg))
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return result
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except IOError:
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return self.errMsg()
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def readU16(self, reg, little_endian=True):
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"Reads an unsigned 16-bit value from the I2C device"
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try:
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result = self.bus.read_word_data(self.address,reg)
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# Swap bytes if using big endian because read_word_data assumes little
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# endian on ARM (little endian) systems.
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if not little_endian:
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result = ((result << 8) & 0xFF00) + (result >> 8)
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if (self.debug):
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print ("I2C: Device 0x%02X returned 0x%04X from reg 0x%02X" % (self.address, result & 0xFFFF, reg))
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return result
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except IOError:
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return self.errMsg()
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def readS16(self, reg, little_endian=True):
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"Reads a signed 16-bit value from the I2C device"
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try:
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result = self.readU16(reg,little_endian)
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if result > 32767: result -= 65536
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return result
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except IOError:
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return self.errMsg()

‎ADS1115/__init__.py

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -3,6 +3,8 @@
33

44
__all__ = ['ADS1115']
55

6+
from .I2C import Adafruit_I2C
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# ===========================================================================
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# ADS1115 Class
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# ===========================================================================
@@ -206,15 +208,15 @@ def getPiRevision():
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@staticmethod
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def getPiI2CBusNumber():
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# Gets the I2C bus number /dev/i2c#
209-
return 1 if getPiRevision() > 1 else 0
211+
return 1 if Adafruit_I2C.getPiRevision() > 1 else 0
210212

211213
def __init__(self, address, busnum=-1, debug=False):
212214
self.address = address
213215
# By default, the correct I2C bus is auto-detected using /proc/cpuinfo
214216
# Alternatively, you can hard-code the bus version below:
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# self.bus = smbus.SMBus(0); # Force I2C0 (early 256MB Pi's)
216218
# self.bus = smbus.SMBus(1); # Force I2C1 (512MB Pi's)
217-
self.bus = smbus.SMBus(busnum if busnum >= 0 else getPiI2CBusNumber())
219+
self.bus = smbus.SMBus(busnum if busnum >= 0 else Adafruit_I2C.getPiI2CBusNumber())
218220
self.debug = debug
219221

220222
def reverseByteOrder(self, data):

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