I2C_class Module

class I2C_class.I2C(H)

Methods to interact with the I2C port. An instance of Labtools.Packet_Handler must be passed to the init function

Example:: Read Values from an HMC5883L 3-axis Magnetometer(compass) [GY-273 sensor] connected to the I2C port

>>> ADDRESS = 0x1E
>>> from Labtools import interface
>>> I = interface.Interface() 
>>> # Alternately, you may skip using I2C as a child instance of Interface, 
>>> # and instead use I2C=Labtools.I2C_class.I2C(Labtools.packet_handler.Handler())

>>> I.I2C.bulkWrite(self.ADDRESS,[0x01,0<<5]) # writing to 0x1E, set gain(0x01) to smallest(0)

>>> I.I2C.bulkWrite(self.ADDRESS,[0x02,0]) # writing to 0x1E, set mode conf(0x02), continuous measurement(0)

>>> vals = I.I2C.bulkRead(self.ADDRESS,addr,6) # read 6 bytes from addr register on I2C device located at ADDRESS

>>> from numpy import int16
>>> x=int16((vals[0]<<8)|vals[1])       #conversion to signed datatype
>>> y=int16((vals[2]<<8)|vals[3])
>>> z=int16((vals[4]<<8)|vals[5])
>>> print x,y,z

init()

enable_smbus()

pullSCLLow(uS)

config(freq)

Sets frequency for I2C transactions

Arguments
freq	I2C frequency

start(address, rw)

Initiates I2C transfer to address via the I2C port

Arguments
address	I2C slave address
rw	Read/write. * 0 for writing * 1 for reading.

stop()

stops I2C transfer

Returns:Nothing

wait()

wait for I2C

Returns:Nothing

send(data)

SENDS data over I2C. The I2C bus needs to be initialized and set to the correct slave address first. Use I2C.start(address) for this.

Arguments
data	Sends data byte over I2C bus

Returns:Nothing

send_burst(data)

SENDS data over I2C. The function does not wait for the I2C to finish before returning. It is used for sending large packets quickly. The I2C bus needs to be initialized and set to the correct slave address first. Use start(address) for this.

Arguments
data	Sends data byte over I2C bus

Returns:Nothing

restart(address, rw)

Initiates I2C transfer to address

Arguments
address	I2C slave address
rw	Read/write. * 0 for writing * 1 for reading.

simpleRead(addr, numbytes)

read(length)

Reads a fixed number of data bytes from I2C device. Fetches length-1 bytes with acknowledge bits for each, +1 byte with Nack.

Arguments
length	number of bytes to read from I2C bus

read_repeat()

read_end()

read_status()

readBulk(device_address, register_address, bytes_to_read)

writeBulk(device_address, bytestream)

scan(frequency=100000)