FPGA I2C sanity check

On 2023-06-28, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
> So we're doing this high speed lidar camera that I've been talking 
> about.  It has a Cyclone V system-on-module, which seems pretty nice, 
> although I haven't gone into it very deeply.
>

> So my question is: Is it sane and reasonable to drag a 2.5V I2C on a 
> Cyclone V up to 3.3V?

0.8V, seems risky,  how much current flows?

Your basic I2C level shifter is one MOSFET per line.

https://cdn-shop.adafruit.com/datasheets/AN10441.pdf

-- 
 Jasen.
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Thanks, all.  Since this is a government program, we decided to do as 
Rick suggested and use an I2C level shifter IC.  Specifically we're 
using the PCA9306D.

The camera has to fly on an airplane in very tight quarters, so space is 
a real problem, but saving one package just wasn't worth the amount of 
documentation work required to get the pull-up resistor thing through 
formal design reviews successfully.

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

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