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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problem of transmitting data from serial device to bluetooth on Arduino
I am using an accelerometer which uses serial communication on Arduino (UART), I wish to transmit the data to a bluetooth module (blusmirf gold) using I2C and finally read it from my android ...
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2answers
418 views
Do all I2C devices have separate read and write addresses?
I'm using a particular I2C device, and when it is connected, I need to write data to it by sending data to address 0x30 but then to read from it I need to read from address 0x31 (or by doing 0x30 | ...
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1answer
30 views
ADXL 345 Noise Issue for my use case
I am building a solution where I want my MCU to wake up based on a trigger generated by accelerometer after detecting an activity. There are a number of samples available for this and I am able to ...
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1answer
225 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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2answers
89 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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1answer
27 views
FT232H read ACBUS9
First time on this board so you will excuse me if the question has been answered before ...
Right down to the nitty-gritty
I have a board based on an FT232H chip, AD bus is used in I2c to ...
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1answer
49 views
Adding High Byte and Low Byte of LSM303DLHC Accelerometer Output
Interpreting LSM303DLHC Accelerometer Output
Hi all,
This is my first StackExchange question ever, so I will do my best to be specific and offer as much reference as possible. I'm currently ...
0
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1answer
175 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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1answer
45 views
Slave I2C timing relative to master clock edges
I am working with the STM32F4 microcontrollers. The I2C peripheral uses a clock setting.
I have been told that it does not matter when the peripheral is used as the slave device.
If that is true ...
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0answers
25 views
Turn on/off serial and I2C display [duplicate]
I have 2 character display, one is controlled by serial another is controlled by I2C. I could control both with serial or I2C alone. But that's not the point.
Now what I want is, to completely turn ...
3
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2answers
50 views
ADC with I2C interface with multiple addresses
I want to connect 31 ADC slaves to a master. The ADCs simply should measure voltage and response its values to the master after request. I thought about using I2C as bus system. The problem is that ...
2
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1answer
56 views
Sensible standard wiring type for long-range I2C
I'm planning on interfacing with some sensor devices via I2C over a long bus, with devices chained every 2m or so, up to 16m in total. I've seen other questions here referring to this from the "which ...
0
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1answer
32 views
Control LCD with TIP121 on Arduino not displaying anything
I'm trying to control the power of an LCD I2C display.
My project uses and Arduino and LCD, but when Arduino goes to sleep, the LCD stays on. So, to solve this problem, I connected a TIP121 transistor ...
2
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1answer
50 views
EEPROM in beaglebone black
I want to disable EEPROM in beaglebone black by unloading i2c-omap driver. Will it create problem in hardware or any other software support? What should I expect ?
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1answer
20 views
Texas Instruments Page/Register Convention - how to find the actual register address?
I am having troubles understanding TI datasheets regarding their DACs... I haven't felt so stupid for quite a while!
To make things as transparent as possible, here is a very literal question.
I am ...
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1answer
221 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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3answers
133 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 ...
5
votes
3answers
9k views
multiple arduino communication (1 master, n slaves)
I would like to develop a master/slave network that consists of:
1 Arduino master that reads sensors and generates velocity ramp profiles based on the sensor signals and then sends those ramps to ...
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1answer
113 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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1answer
52 views
I2C level converter stops bus [closed]
I am trying to get an lcd 16x2 with PCF8574 I2C working with my arduino due. If i connect my lcd with 3.3v (backlight doesn't work, led from the PCF8574 lights up) and upload the i2c scanner sketch ...
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2answers
228 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
52 views
i2c communication between cc3200 and at42qt2120
I am trying to do i2c communication between TI's cc3200 and atmel's touch IC AT42QT2120. I am able to read and write to different memory locations of the touch IC, but i am unable to get it's change ...
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2answers
91 views
Connecting i2c slaves to master over RJ45 style cable?
I'm desigining several modules (e.g. sensors, motor controller, etc.) that need to communicate over I²C.
These modules can be up to 15ft (5m) away from the base module (I²C master - Spark Photon) - ...
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0answers
35 views
CSI/DSI over one meter cabel
Imaging you have a smartphone where the display and the camera is attached with a one meter long cable. What would be the best and most power efficient way to transfer camera (CSI/I2C) and display ...
14
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6answers
8k views
What happens if I omit the pullup resistors on I2C lines?
Just now I realized that the I2C data and clock lines (SDA and SCL) must have pullup resistors.
Well, I've built a couple of clocks using the DS1307 RTC (see datasheet) according to the schematic ...
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2answers
77 views
Cheapest way to get a CAN signal
I have to transfer signals over around five meters. My input signals are I2C or SPI-compatible, but unfortunately it is no good idea to transmit them over such a long distance. Therefore I was ...
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3answers
200 views
How to achieve 57 PWM outputs most easily and cheaply
I need to light up 19 RGB LED strips, which it seems would require 19*3=57 PWM outs and 57 transistors. The transistors aren't an issue, but of course the 57 PWM's is. Most micro controllers simply ...
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2answers
104 views
LMP91000 I2C Write Problem
I've posted this question to TI E2E forum here. I'm cross-posting it here in hopes of casting a broader net.
I'm writing an Arduino library for the LMP91000 (github), and I'm apparently having some ...
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1answer
39 views
Does SMBus spec lie about I2C?
In the SMBus spec it says:
The I²C specifications do not require that a device always acknowledge its own address.
This can confuse a system controller.
If a device does not acknowledge its ...
4
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3answers
6k views
Establishing a proper TWI/I2C communication between a pair of Atmega32
I am a mechanical engineer with the desire of learning electronics stuff.
I am working on these days at learning the TWI(I2C) communication in Atmega32. With a lot of internet search I have managed ...
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2answers
45 views
Why there is no high voltage repeater / voltage translator ic (like max232) for I2C
why I2C don't work don't work with long wire, for UART we have 10 volt translators like max232, for I2C why there is no high voltage repeater ic?
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1answer
425 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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3answers
67 views
PIC24 - testing I2C module dead/alive
I got PIC24FJ192GB106 (64 pin package) and I cannot get the I2C module working at all. What is the easiest and most straight forward way of testing, whether the module is OK?
I am using I2C1 module, ...
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1answer
55 views
PIC24 I2C status bits not set
I am working with PIC24FJ192GB106 (64 pin package), and the I2C module is driving me crazy.
here is the code:
...
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1answer
1k views
Adafruit SSD1306, I2C, ATmega1284p: OLED Display askew/misaligned
Another strange problem here. The setup:
Adafruit SSD1306 OLED board connected to an ATMega1284p via I2C.
Since I "upped" my 1284 to 8MHz (which I needed to to reliably talk to my temperature ...
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0answers
103 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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3answers
760 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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1answer
95 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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2answers
86 views
How to display I2C address in hex
The I2C communications bus uses 7-bit or 10-bit addressing to address slave devices. Taking the more common 7-bit addresses, each packet sent on the bus by the master starts with an 7-bit address ...
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1answer
42 views
Can sampling I2C influence transmission?
I have 200 kHz I2C communication and I am monitoring it with Logic Analyzer that has 100 kOhm input impedance. When I set sampling rate at 2 Mhz everything looks good on the time diagram. On the other ...
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1answer
93 views
Mixed SPI and I2C using ATtiny USI
I've been successfully using the USI on an Attiny84 to talk SPI to a radio module. This is good for hacking up sensors and whatnot as little radio devices. My next sensor project involves a sensor ...
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1answer
82 views
Will MCP23017-E/SP be compatible with an ATtiny85? ATmega328P?
I mainly want to also be able to use the same I/O expanders with ATTiny85 projects since those chips have limited pins.
I will be doing the main prototyping on an ...
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1answer
62 views
why is ground needed to be common in i2c communication?
I'm using i2c for communication between arduino and SBT-150 thrusters , but the problem is that thrusters use 24V and arduino use 5V. So, i want to somehow isolate the two grounds for protection of ...
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1answer
98 views
Voltage regulator like LM 317 which can interface like SPI or I2C
Is there any variable voltage regulator IC similar to LM317 available the output of which can be programmed through a digital interface like I2C or SPI?
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2answers
254 views
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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1answer
155 views
TSL2591 sensor value calculation
I bought an TSL2591 breakout board and wanted to write driver for my board.
After looking at the documentation, i found that i cannot calculate the illuminance value (in Lux) as their was algorithm ...
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2answers
81 views
Is it allowed to stop and restore I2C transmission?
Is it allowed to stop and restore I2C transmission? I would like to stop it in different periods of transmission and then after for example 500ms restore it to the state when it was stopped. I'm ...
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2answers
965 views
Problem with transmitting data from PIC18F45K20 (C18) to MCP23017
I am currently testing the MCP23017 (slave device) 16 bit I/O Expander using a PIC18F45K20 with the C18 compiler to transmit data to the MCP23017. The address pins (A0, A1 and A2) of the MCP23017 are ...
33
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5answers
25k views
Is there a correct resistance value for I2C pull-up resistors?
The datasheet of the 24LC256 EEPROM states that:
The SDA bus requires a pull-up resistor to VCC (typical 10 kΩ for 100 kHz, 2 kΩ for 400 kHz and 1 MHz).
I thought that any resistor with a kΩ ...
4
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1answer
83 views
How long/big is an I2C acknowledge?
I'd like to know, how long/big should be an ACK from a slave to its master? I am communicating with a module using the I2C protocol. But the large blank space in the middle, is this an ACK from the ...
