I²C (Inter-Integrated Circuit) is a multi-drop serial bus invented by Philips (now NXP) for communication between ICs on the same PCB, i.e. short distance.

learn more… | top users | synonyms

0
votes
0answers
43 views

trouble getting two PICs to communicate via I2C

I'm having a bit of trouble getting two PICs to communicate with each other over an I2C line. Both are 16F886, one sitting in the PIC 28-pin demo board, second one sitting inside a board which I ...
0
votes
1answer
34 views

Whats the difference between these three breakout boards for the ADXL345 Accelerometer?

I would like to use the ADXL345 in a schematic im working on right now, but as there is no typical/minimal circuit provided within the datasheet i got stuck. I did a bit of research and found three ...
0
votes
0answers
25 views

ADC input to raspberry pi - I2C vs I2S

I'm trying to create a microphone array and take readings into a raspberry pi. I'm having an 8 bit ADC connected to the pi via I2C (SCL and SDA pins). I'm able to read samples (0-255) into my pi using ...
0
votes
1answer
38 views

SDA line pulled low by slave always?

If due to some problem in slave, The slave is not able to leave the SDA line free , so that master can gain control over it. Its gets low by the slave in between data transfer , but not able to ...
3
votes
1answer
71 views

Why is i2cset giving “resource busy” on my BeagleBone Black?

After trying to get Adafruit's 8x8 LED Matrix python example code to work on both my Raspberry Pi and my BeagleBone Black, I realized there is probably something wrong with Adafruit's code and not me. ...
0
votes
0answers
24 views

I2C Real Time Clock 3.3V [closed]

I'm searching for RTC IC with 3.3V operation Voltage. I looked DS1307 but it needs 4.5V minimum. I have 5V power line on my board but it will not compatible with 3.3V I2C bus and i don't want to use ...
0
votes
0answers
48 views

Accelerometer gyrometer for radxa board - i2c configurable addresses vs spi

I am looking for an accelerometer/gyrometer that has configurable address. It should run on a radxa rock board using i2c, or some spi solution. I am using that board (PRO) ...
0
votes
1answer
68 views

MPU6050 I2C PIC18F458

I'm using MPU6050 with PIC18F45 protocol I2C. On EasyPIC v6 board its just send me back anything that I put in this WRITE command I2C1_Wr(0xD3);. I replaced the ...
0
votes
0answers
20 views

Can the Arduino use this i2c LCD Panel [migrated]

Can the Arduino Mega2560 use the New Haven NHD-0420D3Z-NSW-BBW-V3 LCD panel by controlling it with the New LiquidCrystal library? What cable will you use to connect the LCD to Arduino, are there screw ...
1
vote
0answers
48 views

BH1750FVI with I2C won't work

I have the led driver of Adafruit connected to my atmega32. I adjusted their library for the Arduino, so now I just need a µcontroller and not an Arduino. This thing works. Now I want to control the ...
1
vote
1answer
64 views

SMBus using Silicon Labs C8051F560

I am trying to communicate an arduino with a Silabs F560 Toolstick Daughter Card. On Arduino (Master) I have loaded the i2c scanner program from http://playground.arduino.cc/Main/I2cScanner which ...
0
votes
0answers
6 views

Sainsmart LCD 2004 - LiquidCrytal_I2C library issue unable to compile [migrated]

I bought a Sainsmart LCD2004 from Amazon to use with my Arduino Uno. I understand that since this LCD uses I2C a new library needs to be downloaded. From the sainsmart website I dowloaded the LCD ...
4
votes
2answers
261 views

What are the options if the I2C slave addresses clash?

Now I have ten accelerator sensors (ADXL345) connected to only one PIC16F887 using I2C. The problem is ADXL345 only has 2 I2C slave addresses configurable. So it brings conflict. I know NXP does ...
0
votes
0answers
41 views

Power with Battery + 1wire to i2C

I'm creating a project with Raspberry PI B+ where I will get energy from a truck (12~27v) or/and a solar power (6v 5.6w) to charge a battery and keep the device running until the battery finishes or ...
0
votes
1answer
41 views

Trying to start i2c communication on dspic33fj128gp802, but I cannot write on the SEN bit of the I2CxCON register

Good evening, I was trying to start the communication with the I2C on my pic. I only set the bits in the control register in the code for now and the inizialization of both the pins and the PLL, and I ...
0
votes
1answer
26 views

How does SMBus receive byte command protocol know what to send?

Im programming an I2C device to act as a PMBus slave. Looking at the SMBus protocols (which PMBus is built on) the Receive Byte command has a format described as follows: ...
1
vote
1answer
101 views

Multiple I2C slaves on Intel Edison I2C-6 Bus

I've managed to get my hands on an Edison a few weeks ago and have been messing around with the I2C-6 bus and have encountered a few problems. Problem I mainly have sensors on the I2C line. I can ...
1
vote
1answer
112 views

I2C protocol debugging using oscilloscope

We are testing an I2C accelerometer connected to the ATMega32A micro-controller. The accelerometer was working fine. We can write and read the registers using I2C protocol. When connected to the ...
2
votes
1answer
65 views

Reset I2C slave chip when master goes away

I have a board with a transformer and a MCP23017. This board is connected to another board via 4 wires which bring over power (+5V, GND) and I2C bus for an ATmega328P acting as the master. The ATmega ...
1
vote
2answers
234 views

Communication between micro controllers - I2C, SPI, UART?

Basically I have two microcontrollers that I need to communicate with each other. Both controllers send and receive data. Basic idea that I have: I2C, SPI - What I think we can NOT use these ...
0
votes
1answer
92 views

I2C: How to adress the second page of a eeprom

I have an eeprom and I can't properly adress everything out of the range 0x00-0x1f. Using the Raspberry I send the following I2C command to the eeprom: "sudo i2cset -y 1 0x50 0x00 0x10 0x29" This ...
0
votes
1answer
55 views

i2C multiplexer to use multiple sensor of the same type

I would like to hook up multiple sensor of the same type (temperature, pressure and so on). The problem is that each sensor can only have 2 different unique values for the register, so can't put more ...
1
vote
0answers
100 views

Controlling LCD with MSP430 via I2C backpack PCF8574

I'm at my wits end with this at the moment. I need to interface my MSP430G2553 with the PCF8574 I2C expander in order to drive an LCD display. So far I've had not much luck at all. There is very ...
0
votes
0answers
72 views

How long of a wire and how big of a load can I have for SPI bus?

I have a system where I will connect up to 128 identical magnometer ICs up to an FPGA. I am trying to decide between SPI and I2C for comms. If I use SPI the setup will require 128 + 3 wires IF all ...
0
votes
0answers
150 views

STM32F103 Hangs in I2C_CheckEvent()

I'm trying to connect my both MCU (actually they are two board) together over I2C. one STM32F103ZE (as master) and one STM32F103RE (as slave). This is the code of the Master: ...
0
votes
2answers
103 views

I2C Communications with Arduino

My Engineering Design and Development (EDD) class is working on a high altitude balloon (HAB) and my friend an I are in charge of data collection. It looks like we are going to use an Arduino (Uno or ...
0
votes
0answers
87 views

I2C interfacing with ATmega32 and ArduinoMega2560 failed

I'm trying out I2C interfacing the ATmega32 with Arduino Mega2560 Board without success. The Arduino Board is configured to be the Master Read. The Atmega32 is configured to be the Slave Write. I ...
0
votes
2answers
80 views

I2C Isolation using Switch

In my design I have a controller which is interfaced to the processor (or SoC) using I2C. The processor has internal pull ups for I2C lines so I don't need to put external pull ups. The voltage rail ...
0
votes
0answers
67 views

Voltage/current Monitoring - MAX4172 + ADC vs. INA219

I'd like to add some monitoring of voltage and current on the +5V and +3.3V supply rails of a development board power supply. I'm currently debating between two approaches. The first approach is to ...
2
votes
1answer
112 views

How to connect multiple of the same device to an Arduino using I2C?

I want to use two of the same magnetometer (HMC5883L) with my Arduino, but I cannot figure the code for calling each of them separately. I have read online that connecting multiple devices is ...
0
votes
1answer
105 views

i2c Error in using BeagleBone Black with custom audio cape ( using ti's TLV320AIC3107 codec )

I have made custom audio cape using TLV320AIC3107 codec and here is a schematic diagram. For connection with BeagleBone Black I refer audio cape which is available in market. here is a link: ...
1
vote
4answers
251 views

Noise from switching fans nearby disrupting the I2C bus

I have a RPi controlling a solar system which uses temperature sensors on the I2C bus, the sensors are away from the RPi (20m). The problem is that I have cooling towers and cooling compressors which ...
0
votes
0answers
58 views

I2C slave is not acknowledging for SLA+W but values can be read from/write to registers

We got a wierd problem in a I2C device. We've been trying to solve the issue for more than a week now. This post is about ADXL344 Digital Accelerometer from Analog devices. We made three prototype ...
2
votes
2answers
243 views

Using internal pull-ups for I2C on PIC18F

I'm working with a PIC18F46J53 and it was working quite well without any troubles. Suddenly, I found a hindrance on my path. I used RB4 and RB5 pins as I2C bus pins for communicating with an EEPROM ...
-1
votes
3answers
190 views

Maximum cable length for 5V or 3.3V I2C, UART, or 1-wire signals over Ethernet and how to increase it?

I know similar questions have been asked before (Maximum cable length for 3.3V UART signals) but I would like to know the answer more specifically for a hobbyist. I've been experimenting connecting ...
1
vote
0answers
125 views

RTC DS1307 3.3V I2C and Oscilloscope impedance

I'm working on a library for STM32 to learn I2C protocol (Software I2C, not hardware). I connect my DS1307 (Sparkfun BOB-12708) : (Here is the module schematic) : I remove welding on the SJ2 jumper ...
0
votes
1answer
97 views

Writing data over Serial comm //Arduino & MPU6050 gyro+accelerometer

I'm new to serial communication and I am just scratching the surface, therefore please bare with me. What I need to accomplish is the transfer of the gyroscope data I gather on my Arduino to ...
0
votes
2answers
73 views

What is launchpad's I2C & SPI voltages?

Does anyone know what voltages TI Launchpad's I2C and SPI run at? I think it is 3V3 from a comment on a post, but can't be sure.
0
votes
2answers
117 views

How do you wire up the OV3640 camera module?

I've been wanting to do a project with this module in mind and have found some resources on it (mainly arducam) but I have no idea how to connect it to a micro controller. The data sheets show that ...
2
votes
1answer
137 views

Does biasing of address pins require a resistor?

I'm a total newbie fooling around with a project of mine. I want to use a MCP23071 I2C port extender (Data sheet) for my arduino project. The chip has three hardware pins that must be externally ...
0
votes
2answers
172 views

I2C at 2.4 MHz with five microcontrollers over 2 meters

I have five Teensy 3.1 and I would like to interface them with I2C running at 2.4 MHz. The maximum Line Length will be around 2 meters. Will it work? What's the best way I can wire this up?
1
vote
3answers
138 views

Strange I2C signals emitted from FPGA

I have a ZedBoard FPGA device and I'm trying to implement an I2C interface to communicate with a camera module. I'm using Vivado 2014.2 and I have added an AXI IIC block to my design with the SCL ...
0
votes
0answers
119 views

Beaglebone black i2c-1 file write error

I am using beaglebone black i2c2 pin 19 and 20 of p9. Somewhere in the bet it was told i2c2 has told accessed with i2c-1 in /dev folder. I am booting default amstrom linux from emmc. Hardware is ...
0
votes
0answers
56 views

AVR Error Handling: I2C, SPI etc

How would one go about handling errors in AVR interfaces that do not specifically provide any acknowledgement scheme? For example, I have an I2C temperature sensor which I poll every 1 hour. So every ...
14
votes
2answers
159 views

HDMI and I\$^2\$C

I was having a look at the HDMI pinout and I thought: why would they use I\$^2\$C for the display-host communication? My question here is about the design metrics that lead to this choice. HDMI is a ...
5
votes
4answers
293 views

Properly grounding 2 MCUs using I2C

I'm building a mechatronic system that consists of 1)XY Gantry controlled with PIC32 and a DIY motor shield and 2)control box with PIC24 three potentiometers + room for expansion, typically located ...
1
vote
1answer
65 views

How to debug large I2C bus?

I have a circuit board with lots of soldered SMD chips. There are a few I2C components connected to the same bus and the bus is also connected to a "bus switch" isolation switch. Unfortunately the bus ...
1
vote
1answer
56 views

Arduino I2C level conversion

I'm working with Arduino Uno (Rev 3) to interface a DRV2605 haptic driver to control several ERM/LRA motors using I2C. As I look at examples on the web, I see everyone uses a I2C level conversor to ...
1
vote
0answers
84 views

Debug 2-Wire Serial Interface

How can I debug I2C in Atmel Studio (latest)? I have enabled it as shown inside the I/0 View with TWEN and ...
0
votes
0answers
54 views

9 DoF Sensor Accelerometer Readings Inconsistent

I have the following sensor stick: https://www.sparkfun.com/products/10724 It has an accelerometer, gyroscope, and magnetometer. I have connected it to an arduino and am reading the accelerometer ...