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Added example on how to change I2C address

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commit bb401154f4a222b223fb75ae4c9638a927e56a02 1 parent dae3a42
@nseidle nseidle authored
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97 ... Display/Arduino_Examples/S7S_Example_I2C_ChangeAddress/S7S_Example_I2C_ChangeAddress.ino
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+/*
+ OpenSegment is an 7-segment display with Serial/I2C/SPI interfaces.
+ By: Nathan Seidle
+ SparkFun Electronics
+ Date: June 11th, 2015
+ License: This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license).
+
+ OpenSegment gives the user multiple interfaces (serial, I2C, and SPI) to control a four digit
+ seven segment display.
+
+ This example shows how to change the I2C or TWI address.
+
+ Please Note: 0x71 is the 7-bit I2C address. If you are using a different language than Arduino you will probably
+ need to add the Read/Write bit to the end of the address. This means the default read address for the OpenSegment
+ is 0b.1110.0011 or 0xE3 and the write address is 0b.1110.0010 or 0xE2.
+ For more information see https://learn.sparkfun.com/tutorials/i2c
+
+ Note: This code expects the display to be listening at the default I2C address. If your display is not at 0x71, you can
+ do a software or hardware reset. See the Wiki for more info:
+ http://github.com/sparkfun/Serial7SegmentDisplay/wiki/Special-Commands
+
+ To get this code to work, attached a Serial7Segment to an Arduino Uno using the following pins:
+ SCL (OpenSegment) to A5 (Arduino)
+ SDA to A4
+ VIN to 5V
+ GND to GND
+
+ For this example pull up resistors are not needed on SDA and SCL. If you have other devices on the
+ I2C bus then 4.7k pull up resistors are recommended.
+
+ OpenSegment will work at 400kHz Fast I2C. Use the .setClock() call shown below to set the data rate
+ faster if needed.
+
+*/
+
+#include <Wire.h>
+
+#define DISPLAY_ADDRESS1 0x71 //This is the default address of the OpenSegment
+#define DISPLAY_ADDRESS_NEW 0x50 //This is the new I2C address we want to go to
+
+int cycles = 0;
+
+void setup()
+{
+ Wire.begin(); //Join the bus as master
+
+ //By default .begin() will set I2C SCL to Standard Speed mode of 100kHz
+ //Wire.setClock(400000); //Optional - set I2C SCL to High Speed Mode of 400kHz
+
+ Serial.begin(9600); //Start serial communication at 9600 for debug statements
+ Serial.println("OpenSegment Example Code");
+
+ //Send the reset command to the display - this forces the cursor to return to the beginning of the display
+ Wire.beginTransmission(DISPLAY_ADDRESS1);
+ Wire.write('v');
+ Wire.endTransmission();
+
+ //Send change address command
+ Wire.beginTransmission(DISPLAY_ADDRESS1); // transmit to device #1
+ Wire.write(0x80); //Send TWI address change command
+ Wire.write(DISPLAY_ADDRESS_NEW); //New I2C address to use
+ Wire.endTransmission(); //Stop I2C transmission
+
+ Serial.println("I2C address changed to 0x50");
+
+ //Now we talk at this new address
+
+ //Send the reset command to the display - this forces the cursor to return to the beginning of the display
+ Wire.beginTransmission(DISPLAY_ADDRESS_NEW);
+ Wire.write('v');
+ Wire.endTransmission();
+}
+
+void loop()
+{
+ cycles++; //Counting cycles! Yay!
+ Serial.print("Cycle: ");
+ Serial.println(cycles);
+
+ i2cSendValue(cycles); //Send the four characters to the display
+
+ delay(1); //If we remove the slow debug statements, we need a very small delay to prevent flickering
+}
+
+//Given a number, i2cSendValue chops up an integer into four values and sends them out over I2C
+void i2cSendValue(int tempCycles)
+{
+ Wire.beginTransmission(DISPLAY_ADDRESS_NEW); // transmit to device at new I2C address
+ Wire.write(tempCycles / 1000); //Send the left most digit
+ tempCycles %= 1000; //Now remove the left most digit from the number we want to display
+ Wire.write(tempCycles / 100);
+ tempCycles %= 100;
+ Wire.write(tempCycles / 10);
+ tempCycles %= 10;
+ Wire.write(tempCycles); //Send the right most digit
+ Wire.endTransmission(); //Stop I2C transmission
+}

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