Questions tagged [i2c]
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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I2C slave PWM Verilog problems
I have been trying to get this I2C slave controller to work and send PWM signals, but I still can not drive the PWM. I think that it is an issue with the testbench on maybe how the slave controller is ...
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STM32H7 flashing problem
I have been having a problem with my STM32H725IGT custom PCB, because I can't flash it even though i tried almost everything. I have tried flashing from nucleo's programmer and from stlink-v2 clones ...
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Microcontroller I2C and SPI protocol
I have STM32F401RCT6, ATmega328p, and ESP32 microcontrollers in my circuit. Will I have any problems if I connect the processor directly to an I2C line, otherwise what should I do?
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Building light-following robot with one Arduino and one I2C; Motor.begin command just stops the code from working
This is my code for a light-following robot with an Arduino UNO and an I2C. I'm trying to get it all to work but whenever my Motor.begin command is in the code, ...
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SDA has to wait around one second to go high when reading hex is 0xF8
When I was trying to read 0xF8 from slave, the SDA is still low.
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I2C BME688 Read Request Sent, but no data received
As the title suggests, im interfacing with the BME688 using I2C. The signal I captured using my logic analyzer is shown below. The slave address is 0x76 and register address im trying to read is 0xD0. ...
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I2C with MPU6050 and STM32F407stuck at send address status check
I have the following code for an accelerometer sensor, MPU6050.
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How can I get roll, pitch, and yaw data from an ISM330DLC sensor?
I have code to receive data from both the accelerometer and the gyroscope in X,Y Z axis. According to the datasheet, those are two's complement data. The data read by registers. Can you make sure that ...
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Detecting SCL/SDA ports
I am working with the EFR32MG24 Wireless SoC Family. There is a controller and multiple sensors with custom cables and connectors. For flexibility it would be desirable to connect the cable two ways, ...
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i2c boards distance
I would like to use an I2C bus between 7 boards. first board used as main with the mcu controller, Rest of the 6 with io expanders (16ch each), the distance between the main board to each board is 15c&...
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Managing Multiple SPI Slave Devices with I2C for Slave Selection
I'm working on a project where I have one master device and 64 slave devices. I'm facing a challenge with the SPI protocol's limitation in terms of the number of Slave Select (SS) lines needed for ...
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Understanding ADC digital isolation to avoid ground loops
I have designed a circuit to measure the voltage of a battery. This battery is being cycled all the time by a potentiostat (charging-discharging) which injects positive current to charge the battery ...
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LSM6DS33 IMU data not behaving as expected
This is my first project using an IMU and I don't know what I am doing wrong.
I am using an LSM6DS33 connected to a Raspberry Pi via I2C. When it is sitting still I would expect the gyro values to not ...
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STM32U5 SCL line stays low and hangs
I have two STM32L0 (slaves) and STM32U585 (master) MCUs. I have no issue when Slave transmits data to Master, but if Master transmits signal to Slave, it sends all the 9 clock pulses with address bits,...
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Low level voltage is changing on I2C bus when starting communication
The setup:
I plugged an STEVAL-MKI224V1 board (basic eval board for baro sensor) on a nucleo F411RE. Communication happens through i2c bus.
I added 4.7k pull-up resistors on SCL and SDA.
The wiring:
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Wired network for a lot of ESP8266 / ESP8285
I found this project at GitHub, and I would like to do the same but add a few improvements.
Rotate modules, according to this radiation pattern:
Would it work better?
As I understand ESP8266 doesn’...
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Reading a different value different from what was written in I2C slave device
The following is what I have tried to send to the slave device. I receive 0x00 when I am reading from slave device register address 0xAB. However, it's supposed to be 0x50.
Some info about what ...
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Is I2C ack bit supposed to be one when it's reading data? Why is my ack bit different from TI doc (Understanding the I2C Bus)
The following is the ack bit I observed from my oscilloscope. It looks like there is a glitch in ack.
Next figure is what I found from the Texas Instrument document SLVA704: "Understanding the ...
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FPGA - SCL of I2C is always high when it's in reading mode
I have previously posted I2C(Is pull up resistor mandatory for I2C?). But now I use an internal pull-up resistor from FPGA as @nanofarad suggested. I am using a Zedboard (FPGA) as the controller while ...
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Is pull up resistor mandatory for I2C?
I removed pull up resistors in this schematic. I am using a Zedboard (FPGA) as the controller while the touch screen (FT5316) as the peripheral.
Here is the waveform I got from my oscilloscope:
The ...
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On the Raspberry Pi Pico 2040 Pinout Diagram, why are i2c bus pairs overrepresented across pins?
Picture source: Raspberry Pi's official site
RP2040 is a 32-bit dual ARM Cortex-M0+ microcontroller integrated circuit made by Raspberry Pi Ltd. In January 2021, it was released as part of the ...
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I2C switch current consumption
I'm reading the datasheet of TCA9548A:
https://www.ti.com/lit/ds/symlink/tca9548a.pdf?HQS=dis-mous-null-mousermode-dsf-pf-null-wwe&ts=1698636737382&ref_url=https%253A%252F%252Fwww.mouser.kr%...
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I2C to USB converter with interrupt
I have a touch screen with I2C and interrupt output and I would like to connect this touch screen over a USB cable to a host controller.
I know that it is possible to transfer interrupts on the USB ...
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Pin 4 and 5 are the actual SDA/ SCL on Seeeduino XIAO. Is it possible to use other pins as an SDA and SCL to connect with an LCD display?
I'm doing a similar project as the link below that uses the Seeeduino XIAO, LCD display and the maxim blood oxygen sensor. I'm a little confused with the circuit connection this guy made.
Link to his ...
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MCP23008 I2C speed
MCP23008 data sheet shows 3 modes (100 kHz, 400 khz, 1.7 MHz).
I find no further explanation of it in the document.
Do I need to to be concerned with it or just proceed with the I2C protocol like any ...
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I2C Device Only Responds to First Command
I have a I2C setup which consists of a Raspberry Pi 3 Model B as a master. The Pi is connected to a PCB motherboard with several I2C devices on it. Communication works flawlessly with all I2C devices ...
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Trying to read temperature, but always reading 655.000000 from Si7021 sensor connected to STM32 NUCLEO-F746ZG via I2C
I am trying to read temperature and humidity data from the Si7021 temperature and humidity sensor on an STM32 NUCLEO-F746ZG over I2C, and then send it over UART to be viewed on a computer. After ...
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I2C LCD not working on custom board
I'm working on a custom board for a 4 zone greenhouse heater using the Atmega2561. I can program the board just fine, but I cannot get the LCD working over the i2c bus.
This does not appear to be a ...
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STM32F407 interfacing with DS1307 RTC
The following code sets the initial state of the RTC sensor:
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Can I use 2 modes of I2C operation together in 1 code? For STM32F407 interfaced with MPU6050 sensor
I have my STM32F407 discovery board (master) interfaced with an MPU6050 sensor (slave) via an I2C interface, and it reads and writes data to it.
My questions is, what mode of operation is the stm32 ...
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What could be blocking communication with TDA7706S on a Sony GT520U radio?
I have a Sony GT520U radio which started developing a lot of noise and becoming unresponsive when in tuner mode. Opening it revealed the chipset on the tuner was overheating in less than 3 minutes of ...
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STM32 Nucleo F401-RE no I2C with external power source
So I have a Nucleo F401-RE that I'm using with a Huskylens AI camera via I2C. During development I use the USB to debug and power the board which works fine. I also added 4.7k pull-up resistors to the ...
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VDHL - Using multiple I2C devices with single IP
I need help with a design that I am currently working on. I am using a Spartan 3 that is on a custom board that checks 6 devices using I2C and these devices all have the same address so I am trying to ...
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Do the I2C pullup source and sensor input power sources need to be the same
I am using a Particle Boron or Photon 2 which both state the I2C pullup should be 3.3v.
I currently have a AHT20 temperature sensor and a 20x4 LCD on the I2C bus, which has been running great with the ...
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DS3231 ESP32 I2C problem?
I've got a new board prototype with an ESP32-S3 and a BME688 and and DS3231 on the same I2C bus (using pins 48=SDA and 47=SCL). I run the Examples => Wire => WireScan example making the ...
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Custom i2c with Arduino UNO
For educational purposes, I would like to write my own i2c protocol. Is it possible to write a custom i2c library to communicate using regular ports, or should I use the SCL and SDA ports? Can I mimic ...
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MSP430 i2c txn buffer not moving second buffer command
In this code i have used B0 I2C module.
Problem - I f i I2C_Txn_byte() to send any command it sends the it the first time but doesn't get in the interrupt ISR again
for Example
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Do there exist I2C address-remapping "NAT" chips?
For I2C devices that do not support address changes, do there exist "I2C address proxies" that can sit in front of the statically-addressed device and proxy a different address to the chip ...
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Atmega88p hangs after I2C (TWI) START condition while trying to connect to SSD1306 OLED display
Hello I am currently trying to use my atmega88p micro-controller to display something on the SSD1306 OLED display. In the attached image you can see my setup to connect the mcu to the display. I ...
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What is the significance of this circuit?
It is a part of a sensor circuit on I2C lines. But why are MOSFETs being used to connect pull up resistors for I2C lines?
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I keep Blowing up my i2C (ISO1540) isolator when plugging and unplugging my battery
I am using a ISO1540 to read the SMBus of some BB2590 batteries. The relevant part of the circuit is shown in the images below
The issue that I am having is that sometimes when connecting or ...
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What is needed for a 512Kb HDMI EDID EEPROM? (re: 512KB IC2 EEPROM) [closed]
I'm trying to build an HDMI "dummy" plug that simulates a plugged-in monitor (to trick GPUs into thinking a monitor is plugged in).
Many of these "dummy" adapters exist and are ...
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STM32F030 I2C: Avoiding NACK
I am trying to port my I2C code from STM32F103 to STM32F030. Everything works fine with writes (writes to an eeprom), but when I try to read from an EEPROM (first write transmission with memory ...
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I2C: Can you pull up SDA/SCL lines through an LED?
Everyone likes blinky lights.
Is there any (technical) reason not to pull up the SDA/SCL lines through an LED?
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How to add "cold-reset" MOSFET to a I²C chip? Should it be a P-MOS or N-MOS?
Background
I have a device which sports a couple of "IMU" chips - ICM-20602 and LIS3MDL - which both do not have reset functionality on a pin. They do have the ability to be rebooted by a ...
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If using using multiple PCA9306 for I2C voltage level translation, do I only need one resistor on the master bus?
I have three I2C bus devices: 1) gas sensor (3V), 2) temperature and humidity sensor (3V), and 3) ESP32 (3.3V). They all connect to an I2C bus master: ATMEGA32U4. Using the typical application circuit ...
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What is the purpose of these shunt capacitors on the I2C bus?
The application note on page 13 of the PCA9600 I2C extender/buffer datasheet shows pulldown capacitors C2 on the logic-level side of the I2C bus. I thought with I2C you want to minimize capacitance ...
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How do you wire up the PCA9600 I2C bus extender to use differential signalling at 12V?
I would like to use a 12V differential signal between two NXP PCA9600 I2C buffers to extend I2C at 100kHz to about 15m over 100-ohm twisted pair (CAT6). My original understanding from a brief look at ...
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PCA9557 Port Zero No Output
I've got a really strange issue with some PCA9557 chips. I just had some boards manufactured by JLCPCB with NXP PCA9557s on them as IO expanders. I'm using a Teensy to drive them, and the PCA9557s ...
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