9514af6f22
Installation of the missing py_compile module was factored out into a standalone script which is only compatible with Python 2.
123 lines
4 KiB
Python
123 lines
4 KiB
Python
#!/usr/bin/python
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import smbus
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# ===========================================================================
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# Adafruit_I2C Class
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# Adafruit_I2C.py is essentially a fork of the Adafruit Raspberry Pi I2C module.
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# Any pull requests for this module should be directed to the following, and I
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# can pull them. I'd rather not deviate from the original:
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# https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code/tree/master/Adafruit_I2C
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# ===========================================================================
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class Adafruit_I2C :
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def __init__(self, address, busnum=-1, debug=False):
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self.address = address
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self.bus = smbus.SMBus(busnum if busnum >= 0 else 1)
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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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# Courtesy Vishal Sapre
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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 as err:
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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" %
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(value, reg, reg+1))
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except IOError as err:
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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 as err:
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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" %
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(self.address, reg))
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print(results)
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return results
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except IOError as err:
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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" %
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(self.address, result & 0xFF, reg))
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return result
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except IOError as err:
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return self.errMsg()
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def readS8(self, reg):
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"Reads a signed 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 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" %
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(self.address, result & 0xFF, reg))
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return result
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except IOError as err:
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return self.errMsg()
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def readU16(self, reg):
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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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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 as err:
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return self.errMsg()
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def readS16(self, reg):
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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.bus.read_word_data(self.address,reg)
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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 as err:
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return self.errMsg()
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if __name__ == '__main__':
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try:
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bus = Adafruit_I2C(address=0)
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print("Default I2C bus is accessible")
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except:
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print("Error accessing default I2C bus")
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