I2C_sniffer.sniffer Class Reference

List of all members.

Public Member Functions
def	__init__
def	cancel
Public Attributes
	bit
	byte
	cbA
	cbB
	FALLING
	gSCL
	gSDA
	in_data
	oldSCL
	oldSDA
	pi
	RISING
	STEADY
	transact
Private Member Functions
def	_cb
def	_parse

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Detailed Description

A class to passively monitor activity on an I2C bus.  This should
work for an I2C bus running at 100kbps or less.  You are unlikely
to get any usable results for a bus running any faster.

Definition at line 7 of file I2C_sniffer.py.

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Constructor & Destructor Documentation

def I2C_sniffer.sniffer.__init__	(		self,
			pi,
			SCL,
			SDA,
			set_as_inputs = True
	)

Instantiate with the Pi and the gpios for the I2C clock
and data lines.

If you are monitoring one of the Raspberry Pi buses you
must set set_as_inputs to False so that they remain in
I2C mode.

The pigpio daemon should have been started with a higher
than default sample rate.

For an I2C bus rate of 100Kbps sudo pigpiod -s 2 should work.

A message is printed for each I2C transaction formatted with
"[" for the START
"XX" two hex characters for each data byte
"+" if the data is ACKd, "-" if the data is NACKd
"]" for the STOP

E.g. Reading the X, Y, Z values from an ADXL345 gives:

[A6+32+]
[A7+01+FF+F2+FF+06+00-]

Definition at line 14 of file I2C_sniffer.py.

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Member Function Documentation

def I2C_sniffer.sniffer._cb	(		self,
			gpio,
			level,
			tick
	)		[private]

Check which line has altered state (ignoring watchdogs) and
call the parser with the new state.

Definition at line 119 of file I2C_sniffer.py.

def I2C_sniffer.sniffer._parse	(		self,
			SCL,
			SDA
	)		[private]

Accumulate all the data between START and STOP conditions
into a string and output when STOP is detected.

Definition at line 63 of file I2C_sniffer.py.

def I2C_sniffer.sniffer.cancel

(

self

)

Cancel the I2C callbacks.

Definition at line 141 of file I2C_sniffer.py.

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Member Data Documentation

I2C_sniffer.sniffer::bit

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::byte

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::cbA

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::cbB

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::FALLING

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::gSCL

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::gSDA

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::in_data

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::oldSCL

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::oldSDA

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::pi

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::RISING

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::STEADY

Definition at line 37 of file I2C_sniffer.py.

I2C_sniffer.sniffer::transact

Definition at line 37 of file I2C_sniffer.py.

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The documentation for this class was generated from the following file:

• I2C_sniffer.py