Questions tagged [i2c]
I²C stands for Inter-Integrated circuit, and is a data transferation system that allows connections between computers or microcontrollers and low-level peripherals (e.g. sensors or EEPROMS). It is a multi-master, multi-slave, single-ended, serial computer bus.
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How can I use I2C to talk to sensors?
How can I talk to digital sensors over the I²C interface?
Hardware:
Which pins on the Raspberry Pi's GPIO can I use?
Software:
What I²C libraries are available?
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Firmware 3.18.x breaks I²C, SPI, audio, lirc, 1-wire (e.g. /dev/i2c-1, No such file or directory)
I am using I²C to control a Bright Pi module.
I followed instructions from 'Configuring GPIO - Adafruit' and 'Configuring I²C - Adafruit' to set up the I²C. I have done this a few months ago and ...
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i2cdetect shows every possible address
I was trying to turn on I2C following this tutorial http://www.raspberrypi-spy.co.uk/2014/11/enabling-the-i2c-interface-on-the-raspberry-pi/
But I have problem which I cannot solve.
The command ...
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Raspberry as an I2C SLAVE
Does anyone know how to setup a Raspberry Pi 3 as an I2C slave (in C++)?
Before someone answers saying that it's not possible, it is possible.
Here is a link that says it is possible (pigpio ...
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How to make raspbian load the i2c-dev module on boot up
I have installed 2012-07-15-wheezy-raspbian, and the i2c-dev module and i2c_bcm2708
are there and work with i2c-tools.
How do I get the i2c-dev module etc. to load at bootup?
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Safest way to connect Raspberry Pi to Arduino Uno R3
I am working on a robot using an Arduino Uno R3 and I wanted to have the ability of controlling the Arduino wirelessly, like stopping the Arduino without having to pull the power-plug every time.
I ...
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Meaning of cmd param in write_i2c_block_data
I am testing i2c communication between Pi and Arduino.
The doc says:
write_i2c_block_data(addr,cmd,vals) Block Write transaction. int addr,char cmd,long[] None
I have this test:
On Pi:
...
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How to use a DS18B20 temperature sensor in my Pi?
I have a few DS18B20 temperature sensors. These are normally used in Arduino projects, but I don't see why not to use them with a Pi. There is a software called DigiTemp that seems to drive the device ...
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Is there an I2C Library
Is there a simple library to talk to I2C for C++? I have found some stuff for python and Java, but I wanted C++. I was hoping someone has ported the Arduino Wire library so I could use code I have ...
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Is it possible to communicate with I²C devices via the GPIO? [duplicate]
Is it possible to communicate with I²C devices via the GPIOs?
Also, are there any existing drivers or libraries that make this possible from Python?
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Pi 4 I/O interface options... and where to find them
The BCM2711's hardware documentation lists multiple I/O interface options. Among others these are:
up to 6 × I2C,
up to 6 × UART (muxed with I2C),
up to 6 × SPI (only five exposed on Raspberry Pi ...
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Controlling 400 LEDs from a raspberry pi
I have a client who has several large bronze signboards, each with 100-150 little light bulbs on it, totaling approximately 400 bulbs. The bulbs are turned on and off on a schedule, currently by hand ...
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Current state of I2C in Kernel and Kernel version in general
I need to use kernel drivers for some I2C peripherals, so I need kernel I2C support. As already discussed in a previous question, the current 3.1.9 kernel doesn't provide support for the SoC's I2C ...
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i2cdetect doesn't catch ANY address. How can I tell if I2C working correctly?
I'm having difficulties interfacing the Raspberry Pi to basically any I2C sensor. I've gone through a lot of tutorials on how to get the I2C driver to work and my connections are correct. Still, ...
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How do I bit bang I²C master?
I've installed RPi.GPIO. It doesn't support I²C yet, but can I use it to bit bang I²C?
I would just need the Raspberry Pi to be the master.
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What does raspi-config do when you enable i2c?
Is there any documentation for the raspi-config command that would explain what it actually does when enabling i2c?
In the past I have just removed the i2c blacklist, added the modules and made sure ...
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PoE hat fan activation on OS other than Raspbian
I'm aware that the only officially supported OS that the PoE hat works on is Raspbian. I can confirm that both my hats work, and that the fan does switch on and off if I have Raspbian installed on the ...
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What bitrate can I get from an i2c bus?
In short, what is the maximum bitrate that can be achieved writing to an I2C bus from a Raspberry Pi? Should it be the theoretical maximum of 100KB/s?
In more detail, I'm writing to an I2C bus from ...
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I2C devices not detected
I'm running raspbian on my pi and followed this tutorial to get the i2c going. i2cdetect -y 1 used to detect my i2c devices but doesn't anymore. The sensor is connected like this:
Could this be a ...
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Adafruit bonnet & adafruit-circuitpython-motorkit return "ValueError: No Hardware I2C on (scl,sda)=(3, 2)"
on the line kit = MotorKit(), the error diagnostic is:
ValueError: No Hardware I2C on (scl,sda)=(3, 2)
quality standards quality standards quality standards quality standards quality standards ...
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Controlling a official lego servo motor via Raspberry Pi
I am able to control a simple servo motor such as SG90 by using pulse-width modulation. However when it comes to controlling a 88004 LEGO Servo Motor it is simply a nightmare.
By using PWM all I ...
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GY-521 module / MPU-6050 3x Accelerometer not detected by i2cdetect
I got this GY-521 module (https://www.aliexpress.com/item/MPU-6050-3-Axis-gyroscope-acce-lerometer-module-3V-5V-compatible-For-Arduino/2035920870.html?spm=2114.13010608.0.0.pRpLS4) and no matter what ...
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Can we use other GPIO pins as I2C
I would like to connect multiple I2C devices to my Raspberry Pi. Can I do that? What do i need to take care? Also is there any library which will output I2C on other GPIOs?
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How to allow I2C access for non-root users?
How do you allow non-root users to access I2C on the Raspberry Pi 2?
I've compiled this code for accessing an MPU6050 sensor via I2C, and it works perfectly, but only when I call it via sudo.
I ...
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How to setup a MCP79410 real time clock?
I was trying to set up a MCP79410 real time clock (RTC) and had to search quite a bit until I found a way to integrate the RTC's time signal into my Raspbian Jessie:
Apparently, even there, some ...
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MMA8452 I2C module
I am working on Raspberry Pi Model B.
I am trying to interface this device over the I2C Bus on the Rpi.
My hardware Connections are:
RPi Accelerometer
Vcc P1_1 ------------------...
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PREEMPT_RT and RPi Drivers
I'm planning to do some realtime control loop tasks with the RPi. In this post PREEMPT_RT and Xenomai were proposed. I'm thinking about trying PREEMPT_RT, as I'd like to keep it as simple as possible.
...
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Raspberry Pi as slave
I am using a Pi compute module and wish to make two of them to communicate to each other.
I have hooked up some slave I2C devices to it (RTC, Temperature sensor). So I don't think making Pi as slave ...
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Pi to Pi Communication over GPIO / USB
I have a Pi Zero that I would like to use to communicate with a B+.
In theory I can connect an adaptor cable and a WiFi or Ethernet USB dongle to the Zero, and do the same on the B+.
However, as an ...
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I2C repeated start with BitBanging not working - Pigpio library on Raspberry Pi B+
First post here on the forum! Been getting a lot of help here from all the past posts and I am grateful for such a great community.
I have been trying to use Repeated Start by using the PIGPIO ...
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Raspberry as I2C Slave, how to slow down transfer rate?
I have had minor success using the PIGPIO library and interfacing the Pi as an I2C Slave (Using GPIO Pins 18 and 19 as SDA and SCL) with a Campbell CR1000X Datalogger
I am encountering a problem ...
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MMA845X accelerometer mapped at 1C
I have a MMA845X accelerometer mapped at 1C:
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- 1c -- -- -...
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Raspberry Pi DPI only works over short distances. Why?
I would like to use the Raspberry Pi 3B+ to operate the rectangular HyperPixel 4.0 touchscreen from Pimoroni. However, I don’t want to plug the touchscreen directly onto the Raspberry Pi, but instead ...
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What hardware peripherals might be capable of reading 6.144, or better yet, 9.216 megabits/second?
I'm hoping to interface a Raspberry Pi 4 with an 8 channel, 48 kHz ADC. Ideally a 24 bit ADC, which if my math is right means 9.216 megabits per second. But a 16 bit ADC would be acceptable: that ...
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Read data from Si7021 via I2C
I have an Si7012 temperature / humidity sensor attached to the i2c pins on my Raspberry Pi. Specifically, I have the Adafruit "break-out" with this sensor attached https://www.adafruit.com/product/...
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Prevent wake-from-halt
I have an SMBUS (I2C, SMART Battery/charger) communication connected to the RPi:
Pin 3 GPIO2 SMBUS SDA
Pin 5 GPIO3 SMBUS SCL
When pin 5 is connected, the system will wake up after approx 5-20 secs ...
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Does the Raspberry Pi support I2C multi-master configurations?
We are using Raspberry Pi 2 single board computers for test automation (they run our feature test against an actual DUT).
Our Device Under Test (DUT) uses I2C multi-master mode to communicate with its ...
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Is there a tool to read and write data using I2C?
I am testing out some I2C connected hardware and my C program is working fine using Wiring Pi. However, what I wanted to do was read a byte or write a byte to the slave device from the shell. I ...
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How to use 2 x MCP23017?
I need to control 32 L.E.D's individually, now looking through the forum, the common solution is to use MCP23017 chips, as they can control 16 l.e.d's. With that in mind, I would require two chips.
...
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How can I automatically update the hwclock with NTP when I have internet connection
I'm using an RPi with Raspbian which runs the NTP-daemon by default. I have connected an rtc-ds1307 external i2c hardware clock. I was following the instructions given here to set it up:
http://learn....
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How to install smbus to virtualenv?
How to setup python-smbus in the virtual env? Pip does not find any appropriate package. Is there a way to make main python installation's libraries visible to virtual env?
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Why many RaspberryPi add on has pull up resistors?
I was looking at the I2C in RaspberryPi and I saw that they are pulled by 1.8K resistors(I am not talking about the ID pins). On the other hand, I got one of those RTC and they got two 222Ohm pull up ...
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How to read data from arduino with raspberry pi via I2C
I have connected Raspberry pi 2 model B with arduino uno via Bi-Directional Level shifter.
Raspberry pi GND ---------- GND Arduino
3.3v ---------- 5v
...
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Raspberry Pi/"Arduino" communication
I'm looking to use a raspberry pi to speak to multiple "arduino" ATMEGA328p ICs (through a logic-level converter). I figure I can do this reasonably well over the GPIO RX/TX and use qualifiers to let ...
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Is there a python library to allow I2C between Pi (master) and Pico (slave)
I want my Raspberry Pi to control my Raspberry Pico. I'm trying to send bytes of data to the pico and then read the data on the pico so that I can take different actions depending on the data sent (e....
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Changing the baud rate of additional I2C busses
for some project I need 5 sensors. Their I2C address is fixed and can be changed to another fixed value by soldering. So without an I2C multiplexer (which I don't have), I need at least 3 I2C busses.
...
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Raspberry PI as I2C slave - problem sending data back
First, I read Raspberry as an I2C SLAVE and followed everything in there. Great thread. However, this thread does not address anything about sending data back.
This is the scenario: rPI4 as master, ...
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How to fix Remote I/O Error Whilst Using i2c OLED
I was using my i2c OLED perfectly well when seemingly for no reason I started getting the Remote I/O Error when I ran my Python program. For some reason this was fixed by installing i2c tools again. ...
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smbus Import Error
I'm trying to use the module 'smbus' on python3. I've downloaded it - when I try to download smbus, it says that smbus is up to date and installed. However, when I try to use it, it says the module is ...
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"I2C transfer failed" flooding the logs
I recently got a RPI 3, on which I installed ArchLinux, aarch64 version. I just saw that an I2C error message is flooding the logs. Exact error is:
kernel: i2c-bcm2835 3f805000.i2c: i2c transfer ...
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