BMP085 and second IC2 line
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BMP085 and second IC2 line

by gians on Mon Sep 24, 2012 12:00 pm

Hi
I'm doing some experiment with your item BMP085
I'm doing exactly step by step as written on your guide.
I 'm using your Occidentalis distro.
But I found the device only typing
$ sudo i2cdetect -y 1
Code: Select all | TOGGLE FULL SIZE
 0  1  2 3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- 77

where is my mistake?

Or how do I change the code to find the device on the second line IC2?

many thanks in advance
Giuseppe
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Re: BMP085 and second IC2 line

by adafruit_support_rick on Thu Sep 27, 2012 7:59 am

To have multiple BMP085 devices on the same I2C bus, they would have to have different slave addresses. Unfortunately it is not possible to assign different addresses to these devices. They are all preconfigured at address 0x77.

To use two of them, you would have to have a separate I2C bus for the second unit.
Last edited by adafruit_support_rick on Thu Sep 27, 2012 8:06 am, edited 1 time in total.
Reason: updated answer
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Re: BMP085 and second IC2 line

by gians on Sun Sep 30, 2012 3:37 am

Please what does it mean the 1 instead of 0
which is located at the end of:
$ sudo i2cdetect -y 1
regards

Giuseppe
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Re: BMP085 and second IC2 line

by adafruit_support_bill on Sun Sep 30, 2012 5:16 am

1 refers to the I2C bus. Installed I2C busses can be listed with the -l option:
http://www.lm-sensors.org/wiki/man/i2cdetect
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Re: BMP085 and second IC2 line

by isubasti on Tue Oct 02, 2012 1:30 pm

It is actually possible to have several I2C devices connected to the same I2C line using an I2C multiplexer/switch such as this IC:http://www.ti.com/product/pca9548a.
It will be great if adafruit can make a breakout board for those I2C multiplexer/switch as there are more devices using I2C on adafruit's store
and we possibly need that to use several devices with the same I2C address.

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