SparkFun Differential I2C Breakout Termination Resistors

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madlan
Posts: 3
Joined: Tue Dec 03, 2013 2:25 pm

SparkFun Differential I2C Breakout Termination Resistors

Post by madlan » Mon Jun 11, 2018 4:12 am

Hi,

I'm interested in purchasing a few of your PCA9615 boards for an ongoing project.

However, I cannot see how to disable the termination resistors on your board? Is it going to be a case of removing the 6 resistors on all boards except the termination one?

I have 24 BME280 boards that i'd like to connect to an ESP32. They are spaced out 50cm over 4 metres X 3 levels with the ESP32 in the centre.

BME280 ------ BME280 ------ BME280 ------ BME280 ------ BME280 ------ BME280 ------ BME280 ------ BME280


BME280 ------ BME280 ------ BME280 ------ BME280 ESP32 BME280 ------ BME280 ------ BME280 ------ BME280


BME280 ------ BME280 ------ BME280 ------ BME280 ------ BME280 ------ BME280 ------ BME280 ------ BME280

(Total length is 4 metres, height is 1 metre. Longest run will be 2.5 metres)


Thanks
madlan

n1ist
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Joined: Wed Mar 22, 2006 11:02 am

Re: SparkFun Differential I2C Breakout Termination Resistors

Post by n1ist » Mon Jun 11, 2018 6:22 am

I looked over the board; I agree with you that the way to disable termination is to remove the resistors. Given that there's only one connection for the differential i2c and ideally you would have two for your application, it may be easier to spin your own board with the PCA9615 and BME280, with the appropriate connectors and termination.

/mike

madlan
Posts: 3
Joined: Tue Dec 03, 2013 2:25 pm

Re: SparkFun Differential I2C Breakout Termination Resistors

Post by madlan » Mon Jun 11, 2018 7:43 am

Two connectors and some pads to cut for the termination resistors would be cool on the next revision :)

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