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.

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If an I2C device does not appear in i2cdetect does it mean the device is potentially broken?

I am trying to get an I2C OLED (128x64) display working on a BeagleBoneBlack. Unfortunately, no matter what I2C port I try I cannot see the device when using the i2cdetect utility. As you can see ...
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58 views

Is it possible to connect more than one device on the same SPI?

Is it possible for someone to connect multiple sensors to the same microcontroller's SPI or I2C port? If it's possible, how would someone alternate between devices?
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44 views

Microchip 9808 temperature sensor - Incorrect calculation result

I am using a Microchip MCP9808 I2C temperature sensor (https://learn.adafruit.com/adafruit-mcp9808-precision-i2c-temperature-sensor-guide/overview). I'm having problems being able to calculate the ...
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17 views

LSM9DS0's Accelerometer not reading correctly

I have a LSM9DS0 Gyroscope/Accelerometer/Magnetometer breakout board. I am using an Arduino Uno which operates on 5V. The LSM9DS0 is communicating to the Uno using I2C through a Logic Level Converter. ...
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2answers
42 views

LCD 2x16 I2C ST7032i

I write a code using Atmel ASF for SAM devices for LCD 2x16 with ST7032i controller. I've encounter an issue about reading and specifically "busy flag reading". How can i perform read instruction to ...
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56 views

I/O pin as I2C wire

In my application,I need 2 I2C interfaces as I need to interface EEPROM and smartcard. Can we use I/O pin as I2C wire? How? Is it feasible?
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72 views

How to make this I2C OLED screen work? (probably SH1106)

I have just received this screen: link but unfortunately it's different then other showed in reviews. That's my version link It's probably based on SH1106 but I can't make it work. I have tried few ...
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4answers
85 views

EEPROM I2C driver hanged during ESD test?

In our prototype , we have a I2C based EEPROM . During ESD Test(High potential spark is injected into system for a very short moment), the drivers hangs in the I2C code. Basically there are while ...
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1answer
34 views

FXOS8700CQ - Arduino core I2C doesn't work, SoftI2C does

I use the Arduino core libraries in my latest project (ATMega328P MCU) I'm trying to talk to an FXOS8700CQ via I2C. Reading register 0x0D should return 0xC7. The typical Arduino Wire library method, ...
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34 views

ATXMega32D4 Two Wire Interface

Lately i have been using ATMega32A and ATMega324PA and learnt various coding techniques in AVR C programming. One such code i wrote is avr_twi.c for communicating with an I2C accelerometer Now i got ...
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1answer
76 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 ...
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40 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 ...
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51 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 ...
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1answer
47 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 ...
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1answer
90 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. ...
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1answer
70 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) ...
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1answer
98 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 ...
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59 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 ...
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1answer
70 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 ...
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2answers
264 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 ...
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45 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 ...
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1answer
57 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 ...
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1answer
32 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: ...
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1answer
133 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 ...
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1answer
121 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 ...
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1answer
67 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 ...
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2answers
285 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 ...
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1answer
106 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 ...
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1answer
67 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 ...
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141 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 ...
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74 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 ...
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0answers
236 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: ...
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2answers
121 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 ...
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96 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 ...
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2answers
83 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 ...
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79 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 ...
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1answer
136 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 ...
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1answer
137 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: ...
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4answers
257 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 ...
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0answers
63 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 ...
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2answers
288 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 ...
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3answers
266 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 ...
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145 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 ...
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1answer
112 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 ...
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2answers
76 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.
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2answers
164 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
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1answer
143 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 ...
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2answers
191 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? ...
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3answers
150 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 ...
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133 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 ...