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I2C at 9600 baud?

Posted: Tue Feb 05, 2019 10:14 pm
by NullPointerException
Hello,

I've read that the I2C bus speed can be changed by putting a line in /boot/config.txt, however I have a device that for some stupid reason requires the I2C bus speed to be running at 9600 baud. I'd like to make sure that the RPi supports non-standard I2C speeds before I go jumping into this project, as I would need to order some breakout boards for the special connector and stuff...

Thanks in advance!

Re: I2C at 9600 baud?

Posted: Wed Feb 06, 2019 6:51 pm
by Andyroo
Are you sure that’s not serial (RS/232 or similar)?

The reason I ask is low speed I2C is 100 kbit/s :lol:

Edit: Just looked at the NXE site and technically the bus speed starts at DC :o

Re: I2C at 9600 baud?

Posted: Thu Feb 07, 2019 1:59 am
by NullPointerException
Andyroo wrote:
Wed Feb 06, 2019 6:51 pm
Are you sure that’s not serial (RS/232 or similar)?
The reason I ask is low speed I2C is 100 kbit/s :lol:
Yep, I am 100% sure. And yeah I know, that's why I was asking if the Pi supports non-standard speeds.

Re: I2C at 9600 baud?

Posted: Thu Feb 07, 2019 2:46 am
by rzusman
You could always bit-whack it at any baud rate you want.
I2C is ugly, but I wrote a bit-whacked interface in assembly language decades ago, so it’s not impossible.

Re: I2C at 9600 baud?

Posted: Thu Feb 07, 2019 9:20 am
by B.Goode
An Internet search for "Raspbian config.txt i2c" found this: https://www.raspberrypi.org/forums/view ... 1#p1426681

It contains a reference to the  BCM2835 ARM Peripherals specification which should presumably contain a definitive answer.