Which pullup resist. value to use for I2C

[msmax]

i2c resistor values

How to determine which value is the best to be used as pullup for I2C?

Any idea's?

 

[Rayengine]

i2c 400 khz pullup

It really depend on the speed of link in your applications. You can check the pulse waveform to see the rise edge before determing the values. Some common value will be 1K to 10K ohms.

 

[flaxa]

i2c pull up resistor values 1 mhz

I use 4k7 @ speed of 125kHz.
~flaxa

 

[flaxa]

i2c pull up 1k or 10k

I use 4k7 @ speed of 125kHz.
~flaxa

 

[Al Farouk]

i2c pullup value

I saw many circuits use 4.7K pull up with 100 series resistor

 

[arturt134]

how to calculate pull-up value for i2c

Typically I've used 10k pull-ups. Works fine with 100kHz and 400kHz I2C clock.

 

[mrcube_ns]

400 khz i2c pull up value

If you have oscilloscope you can see which resistor works fine (changing resistors you change edges of i2c signal). I use 4k7 for 100k transfer, but in some projects with PCF8583 I used 1k to get perfect square signals on i2c link.


Mr.Cube

 

[jhonny_yang]

4K7Khz and 22K for 100Khz and i test 1K for pararell i2c 10 devices

 

[barrybear]

If your project is breadboarded start with 4k7 and work up with a scope to determine optimal value.

Barrybear

 

[mitaka]

usually you can read in datasheet what resistor to use
for example in 24xx256 eeprom "(typical 10 k for 100 kHz, 2 k for
400 kHz and 1 MHz)."

 

[joco]

It also depends on how many devices you have in that bus... I'll remember that Philips has some formulas to calculate resistor values. And don't forget series resistors from each device in bus; 100 - 150R fits most cases.

~joco~