Tagged Questions

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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9 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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26 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
21 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
53 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
93 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
57 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
179 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
72 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
47 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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0answers
57 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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0answers
71 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
65 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
89 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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0answers
66 views

open(“/dev/i2c-1”,O_RDWR) return -1, i2c-1 device couldnt open [migrated]

I have a little problem about my app. Firstly I install package i2c-tools, I give all permission to all user for dev/i2c* files. After, add the line i2c-dev in ...
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0answers
66 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
65 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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0answers
38 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
86 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
63 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
248 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
47 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
196 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
139 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
91 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
66 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
72 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
76 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
135 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
159 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
94 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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0answers
93 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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0answers
46 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
150 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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4answers
260 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
62 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
53 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
68 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
45 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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0answers
92 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 ...
0
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1answer
613 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
436 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
69 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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votes
2answers
287 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
155 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
44 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
440 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
180 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
78 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. ...
3
votes
1answer
324 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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1answer
331 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. ...