NullPointerException
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I2C at 9600 baud?

Tue Feb 05, 2019 10:14 pm

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!

Andyroo
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Location: Lincs U.K.

Re: I2C at 9600 baud?

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:

Edit: Just looked at the NXE site and technically the bus speed starts at DC :o
Need Pi spray - these things are breeding in my house...

NullPointerException
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Joined: Tue Feb 05, 2019 9:49 pm

Re: I2C at 9600 baud?

Thu Feb 07, 2019 1:59 am

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.

rzusman
Posts: 346
Joined: Fri Jan 01, 2016 10:27 pm

Re: I2C at 9600 baud?

Thu Feb 07, 2019 2:46 am

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.

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B.Goode
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Location: UK

Re: I2C at 9600 baud?

Thu Feb 07, 2019 9:20 am

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.

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