CJ0Y.png' alt='How To Use I2c Tools' title='How To Use I2c Tools' />I2. C communication between a RPI and a Arduino. I want to send data from my RPI master to one or multiple Arduinos slave via I2. C bus. Hint The RPI is running with 3. How To Use I2c Tools' title='How To Use I2c Tools' />V while the Arduino is running at 5. V. I read some tutorials where they used a level shifter for the I2c communication. This is NOT needed IF the RPI is running as master and the Arduino is running as slave device. You can use the I2. Best Torrent Site For Windows Software here. C bus without level shifter as only the master will push the data line highEdit 8. Pete G. wrote a comment which describe it much better One small point, I2. C data bus will be bi directional, not single as you stated. Both devices will send data on it. The reason it works, is that the devices using it have open collector drivers, and pull up resistors to the power supply rail. An arduino does not have any pull ups installed, but the P1 header on the Ras Pi has 1k. Data is transmitted by pulling the lines to 0v, for a high logic signal, and then letting them float pulled up to the supply rail for low logic. Because there is no pull up resistor in the Arduino and because 3. AN86526 describes an I2Cbased bootloader for PSoC 4. In this application note, you will learn how to use PSoC Creator to quickly and easily build an I2Cbased. VL53L0X World smallest TimeofFlight ToF ranging sensor, VL53L0CXV0DH1, STMicroelectronics. This 8bit inputoutput IO expander for the twoline bidirectional bus I2C is designed for 2. V to 6V VCC operation. QqeUIpiOmldZAmcojB-xUGrdm2K9nUK67HGYfpeTL8kpr8I08_UZFc560QftZ4fw=h900.png' alt='How To Use I2c Tools' title='How To Use I2c Tools' />Arduino everything works as it should. Remember though that if other I2. C devices are added to the bus they must have their pull up resistors removed. More details. Buy your RPi here and help support neophob. Prepare I2. C on the RPIThere are tons of tutorials out there how to enable I2. C on the RPI. Thats why I keep the following part very short. Remove I2. C from the Blacklist 1. Load i. 2c. dev addto the end of etcmodules. Install i. 2c tools. Allow pi user to access the i. Now reboot the RPI. After that you should see the i. T 1 root i. 2c 8. Apr  4 1. 4 2. 6 devi. T 1 root i. 2c 8. Apr  4 1. 4 2. 6 devi. Now we run a simple test, scan the i. Hint if youre using the first revision of the RPI board, use y 0 as parameter. The i. 2c bus address changed between those two revisions. Prepare the Arduino Slave. Load this very complicated sketch to your Arduino 1. Wire. h void setupWire. Wire. on. Receivereceive. Event register event. Serial. begin1. 15. Serial. printlnhello void loop delay1. Eventint how. Many int a0 whileWire. Wire. read a Serial. Serial. printlna Prepare the RPI Master. Ok we have a listening Arduino client, we now need a I2. C Master for the RPI. Most examples out there are using c Wiring. Pi or python. Im more that Java guy and was lucky I found the pi. Github. Make sure you installed a hard float JRE on your RPI Oh and dont forget to add. PATHPATH usrlocaljavabinto your. I wrote a quick hack, that sends data to an I2. C device. 12. 34. I2. CBus import com. I2. CDevice import com. I2. CFactory public class I2. CExample param argspublic static void mainString args throws Exception System. I2. C Sender, parmeter Paket size Loop count int size Integer. Intargs0 int loops Integer. Intargs1 System. Starting, i. System. I2. C bus instancefinal I2. CBus bus I2. CFactory. InstanceI2. CBus. BUS1 System. out. I2. CDevice arduino bus. Device0x. 04 byte buffer new bytesize for int i0 ilt buffer. System. out. printlnsend buffer now long l System. Time. Millis writeint address, byte buffer, int offset, int size throws IOException        arduino. System. current. Time. Millis l arduino. System. out. printlndone in neededms         Connect RPI with the Arduino. You need to connect 3 cables 1. RPI               Arduino UnoDuemillanove GPIO 0 SDA lt Pin 4 SDAGPIO 1 SDL lt Pin 5 SDLGround       lt Ground. I connected the Arduino USB connector on the RPI itself to power the Arduino and debug the Arduino sketch on the RPI itself using. Scan now the i. 2c bus, you should see the Arduino slave 1. Advanced Stuff. Per default the I2. C bus is running at 1. Hz. You can increase the I2. C bus speed to increase the data throughput. Keep in mind that a faster speed means you ightrun into troubles if youre using longer cables. Increase the I2. C speed on the RPI You can load the I2. C module with an optional parameter which define the I2. C speed, in the following example I use 4. Dexis Software Cost. Hz 1. 2sudo rmmod i. If you want to make that change persistent use this command 1sudo bash c echo options i. Edit 2. 5. 4. 2. 01. I first used a I2. C speed of 1. 20. Hz. That worked for 3 devices, if I connected more devices on the I2. C bus it started to be unstable. Increase the I2. C speed on the Arduino You need to change some source files, close the Arduino IDE and open the Arduino library located at utilitytwi. TWIFREQ 1. 00. 00. L and change it to 1define TWIFREQ 4. L was 1. 00. 00. LThe Arduino use a hard coded I2. C buffer size of 3. If you send more than 3. Arduino will crash and you need to power cycle the board I changed the buffer size from 3. Arduino library files make sure the Arduino IDE is closed 1. TWIBUFFERLENGTH 9. BUFFERLENGTH 9. 6 was 3. Recompile your sketch and reupload it. Test it Now its time to start the Java code, send 9. I2. CExample 9. 6 3. Starting, i. 2c size 9. I first used the default I2. C clock speed of 1. Hz, the RPI needed about 1.