96 lines
2.3 KiB
Arduino
96 lines
2.3 KiB
Arduino
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/******************************************************
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Arduino I2C Sniffer
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2011 J. M. De Cristofaro
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CC-BY-SA 3.0
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this code is unsupported -- use at your own risk!
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connect one digital pin each to SCL and SDA
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use pins on PORTD (Arduino UNO/Duemilanove pins #0 - 7)
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do not connect to serial pins (0 & 1)!
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connect GND on Arduino to GND of I2C bus
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*******************************************************/
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/** DESCRIPTION **/
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/*******************************************************
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this code runs a "one-shot" capture, meaning that
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it only captures data once and then dumps it to the
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serial port.
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it starts capturing when it detects the SDA line has
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gone low. it does not check the SCL line (as a proper
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start condition detector would).
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you can adjust the capture window to suit you needs.
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a value of 300 is long enough to catch one byte sent
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over i2c at the 100 kbit/s standard rate. the sample
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data is good enough to show you the sequence of events,
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but little else.
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if you need very specific, time-aligned data, you should
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use a logic analyzer or sampling oscilloscope.
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*******************************************************/
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// assign pin values here
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const char sda_pin = 2;
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const char scl_pin = 7;
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// sampling window
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const int data_size = 250;
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// array to contain sampled data
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boolean captured_data_scl[data_size];
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boolean captured_data_sda[data_size];
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// housekeeping booleans
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boolean captured;
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boolean dumped;
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void setup()
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{
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SerialUSB.begin(250000);
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pinMode(sda_pin, INPUT);
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pinMode(scl_pin, INPUT);
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captured = false;
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dumped = false;
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attachInterrupt(scl_pin, blink1, RISING);
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SerialUSB.println("Good to go, chief!");
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}
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// main loop: waits for SDA to go low, then
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// samples the data, then formats and dumps it
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// to the serial port.
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volatile byte state = LOW;
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volatile byte val[data_size];
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volatile byte x=0;
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volatile byte y=0;
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void loop()
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{
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// digitalWrite(13, state);
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if (y==data_size)
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{
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for (int i=0; i<data_size; i++)
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{
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SerialUSB.print("0x");
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SerialUSB.print(val[i], HEX);
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SerialUSB.print(", ");
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}
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x = 0;
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}
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}
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void blink1() {
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// state = !state;
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bitWrite(val[y], x, digitalRead(sda_pin));
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x++;
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if (x==8)
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{
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y++;
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x=0;
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}
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}
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