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Interfacing pca9535 with arm using i2c expanders (J5)(i2c5)
Added by Thejas Raj 3 days ago
Hello,
We are trying to interface external pca9535 with the evk via the i2c5 bus. We'll be using the J5 extension on the board to do so.
As far as I know, 0x21 is the memory address that is supposed to be used by pca9535 but i2cdetect -y -r 4 returns
root@mitysom-am57x:~# i2cdetect -y -r 4
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- UU -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- 47 -- -- -- -- -- -- -- --
50: UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- UU --
70: -- -- -- -- -- -- -- --
even when data is coming from pca9535. I suppose the 20 1 column should show 21, but it is not coming up.
Kindly elaborate on the necessary changes to be made in the dtsi files and any other changes that should be made for the proper interface.
Thanks in advance
correction: the extension is J4
even when data is coming from pca9535. I suppose the 20 1 column should show 21, but it is not coming up.
What does this mean? How is data coming from the pca9535 if you cannot talk to it?
As far as I know, 0x21 is the memory address that is supposed to be used by pca9535 but i2cdetect -y -r 4 returns
What are the address A0, A1, A2 pins set to? The i2c address should be 0x20-0x27 depending.
Did you make sure to hook it up to the 3.3V side?
Sorry for the late reply.
We were able to interface the pca9535 after adding the respective nodes for it in the i2c5 bus configuration in the am57xx-mitysom-baseboard.dts file.
Will update if anything else comes up.
Thank you
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