Reasonable
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Connecting multiple SDA SCL Devices

Fri Dec 04, 2015 10:16 pm

Hi,

Is there such a thing (board/controller) that would allow connecting multiple sda / scl devices to raspberry pi?

thanks!

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mikronauts
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Re: Connecting multiple SDA SCL Devices

Fri Dec 04, 2015 10:25 pm

I2C (which is the SDA & SCL signals, plus ground) is a multi-chip bus

You have to:

- watch the total length of the cable
- watch the voltage of the chips

Google "how to use i2c"

There are other limits - for example, some I2C devices only have one possible address, so you cannot have more than one per bus. Others let you select from a number of addresses (2/4/8 usually).

For the devices that only have a single address, you can use an I2C multiplexer, which acts like a switch, selecting between 4 to 8 sub-busses, which can have independent voltages. You can use these multiplexers to connect I2C devices which only have one address.

Reasonable wrote:Hi,

Is there such a thing (board/controller) that would allow connecting multiple sda / scl devices to raspberry pi?

thanks!
http://Mikronauts.com - home of EZasPi, RoboPi, Pi Rtc Dio and Pi Jumper @Mikronauts on Twitter
Advanced Robotics, I/O expansion and prototyping boards for the Raspberry Pi

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ric96
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Re: Connecting multiple SDA SCL Devices

Sat Dec 05, 2015 5:33 am

Reasonable wrote:Hi,

Is there such a thing (board/controller) that would allow connecting multiple sda / scl devices to raspberry pi?

thanks!
Also watch the voltage, some run at 5v but the pi can only handle 3.3v. you will need voltage level converters.
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hampi
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Re: Connecting multiple SDA SCL Devices

Sat Dec 05, 2015 9:33 am

Here is an example what I have done for slow I2C

https://github.com/oh7bf/RPiAOneI2cSens ... ensors.pdf

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