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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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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26 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
230 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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36 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
159 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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63 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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0answers
54 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
43 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
64 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
51 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
128 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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147 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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2answers
75 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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59 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 ...
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33 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 ...
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2answers
145 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 ...
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3answers
165 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 ...
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1answer
59 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 ...
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1answer
46 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 ...
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0answers
56 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 ...
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0answers
39 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 ...
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79 views

USB Audio Stream to Codec

I have been trying to design a USB Audio Interface with an Atmel SAM3U microcontroller and I think I have hit a wall in my thinking process. As a sidenote, I'm relatively new to the world of ...
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1answer
245 views

Arduino: What is the best way to send and receive data with I2C?

I am using I2C to send and receive int values from a RaspberryPi to an Arduino then echoed back to the Pi. The primary problem I am having is with int values larger than 255. A secondary problem is ...
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3answers
426 views

Can I do without I²C pull-up resistors?

I am trying to produce a small circuit, and I am looking to reduce the part count. I recently added an I²C EEPROM which is used once when the system boots up, along with this EEPROM I added two ...
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2answers
64 views

Is it safe to not power this USB to I2C chip when USB isn't plugged in?

I am working with someone on a data logger based on an MSP430. Since it operates on battery power, we want the device to use as little power as possible. We are planning to use this chip (FT201X) to ...
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2answers
263 views

Can I use 74HC14 or NPN transistor instead of MOSFET as level shifter

I have SN74HC14 or BC548 / 2N2222 transistors. I need level shifter for I2C between arduino and RPi. Here's simple circuit from the internet Problem is I don't have any MOSFETs. Can I use NPN ...
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1answer
124 views

Porting Linux drivers specifically I2C

I am developing an I2C driver for an accelerometer. My objectives (actually it's the restriction I have as per the project guidelines given in my institute): use Linux flavour of operating systems ...
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1answer
29 views

AVR TWI Status Codes Complete List

Can anyone provide a link for complete list of status codes for AVR TWI? I am working with DS1307 using TWI, during which at some point I receive a status code of 0x40. However there is no mention ...
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1answer
365 views

Arduino Uno to ATtiny44A I2C communication

I tried to make I2C communication from Arduino Uno to ATtiny44A. Uno as Master and Transmitter code: ...
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2answers
135 views

How to drive a single 7 segment display with I2C?

I am looking for a solution to drive a single 7 segment display with I2C. I found some websites that shows 2 or 4 digits with I2C but I didn't find a solution for driving a single digit. I'm making a ...
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1answer
68 views

MMA8453 accelerometer I2C problem

I ran into an issue with my project. I use Renesas RL78 microcontroller and on one I2C bus I have two sensors: digital compass and accelerometer. Accelerometer type is MMA8453 by Freescale. ...
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1answer
319 views

I2C actually sends inverted data over the line?

It seems to me that I2C is actually transfering inverted bits which sounds a bit odd so I am seeking for a clarification. I2C diagram from here. Let's say we are writing to slave. A zero (0) comes ...
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173 views

Writing to register on I2C device, returns device busy

I am trying to write data to a register on an I2C chip from the Raspberry Pi, when I use i2cdetect I get UU, which I understand is an error. ...
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2answers
113 views

How does multimaster I2C work and its significance?

I am fine with I2C basic communication and implementation? Need info on Multimaster mode of I2C How does multi master I2C work? Advantages over I2C single Master? In what circumstances this multi ...
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2answers
84 views

Arduino I2C and multiple devices

I have created two projects, one with a Tiny RTC and another one with the BM180 sensor to read barometric pressure and temperature. Now I want to combine both. I'm trying to connect both - the ...
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4answers
177 views

Connecting a 9V IC's I2C interface to 3.3v Arduino DUE

I need to connect a TDA7312 to Arduino DUE's I2C interface via SDA/SCL. TDA7312 operates on 9V, Arduino DUE is 3.3v. Is it possible to safely connect it, without burning it? Or what should I use ...
3
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2answers
169 views

Reason for choosing SPI based flash devices over I2C ones [duplicate]

I have gone through the below link which says that u-boot support three type of flash technology http://www.stlinux.com/u-boot/flash 1.Nand 2.NOR 3.SPI Serial Flash I would want to know why SPI is ...
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77 views

I2C Enabled LCD Unreliability

I'm trying to control an I2C Enabled LCD Display using the STM32F0. I have a bunch boards built with the LCDs and a couple of them work all the time, a few work intermittently and a few rarely work at ...
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1answer
74 views

Combine protocols on a U/FTP Cat 6a cable (USB 2.0/I2C)

Main question Can I use a Cat 6a cable for USB communication? On the cable it says 650 MHz, is this sufficient for USB 2.0? The length of the cable would be about 6 meters (about 19 ft). If so, would ...
3
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1answer
88 views

How to read SAA1064 7-segment values

I have a central heating system that displays it's info and error codes on 4 7-segment displays. These displays are driven by a SAA1064, like so: This SAA1064 (datasheet here) receives it's ...
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2answers
74 views

Serial comms over 3m cable, shared with USB

I am designing a system that needs to do serial comms over a standard USB cable, as well as normal USB (but not at the same time). In other words, when plugged in to a PC it will appear as a USB ...
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1answer
124 views

I2C - connecting 5V device to 3.3V host

Is it safe to connect any 5V I2C slave device to 3.3V host? I know, that DS1307 realtime clock can be connected to Raspberry Pi (3.3V IO), because DS1307 just pulls down data lines and 5V voltage ...
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1answer
79 views

BSS138 levelshifter draws 35-40mA current when one side is grounded?

I completely rewrote my question as I found the source of the issue is related to the level shifter only. This is the circuit for a 3.3V to 5V bidirectional levelshifter, used frequently. My ...
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0answers
85 views

Bosch BMI055 Accelerometer/Gyro causes I2C bus to crash when issuing a softreset!

Datasheet: http://ae-bst.resource.bosch.com/media/products/dokumente/bmi055/BST-BMI055-DS000-06.pdf I have recently integrated the Accelerometer of the BMI055 I added a soft reset of the chip at ...
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2answers
272 views

Best way to do I2C/TWI over long distance

I have a project that requires to do I²C/I2C/TWI over a long distance (30 to 40 meters). I've seen some people suggesting lowering the clock-rate to somewhere around 500 Hz, to mitigate the effects of ...
2
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2answers
181 views

AVR TWI (I2C) problem

I am using ATmega32A and 24c16A EEPROM for testing an I2C code. For every state transition, controller responds by changing the status register TWSR. After start ...
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3answers
433 views

Can I use both I2C and SPI at same time with PIC16F1503

Im new to Microchip microcontrollers and I'm looking for very low cost device with I2C and SPI. I want to connect one I2C (ADC) and one SPI device (LCD). I found this very low cost device: However ...
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89 views

GY-521 Unable to set PWR_MGMT_1 register - can't disable SLEEP mode

I am attempting to interface between a custom 8051-based MCU and a new (ebay) GY-521 module (Gyro/Accel chip) using I2C bus. I have written the I2C bit-bang functions myself and they seem to be ...
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1answer
74 views

SWD and i2C hardware layer differences

Both I2C and SWD are two-wire protocols. I wonder what are the main differences of the hardware layer of these protocols and what are the pros/cons of each one? It's also interesting that the maximum ...
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Sending I2C reliabily over Cat5 cables

I am considering implmenting an home automation system around my Raspberry Pi but I found the price and space requirement of inserting a Pi every place some control is required too much but the Cat5e ...