Device connected on i2c doesn't get discovered.

Dip Bhanvadiya

Other Parts Discussed in Thread: TCA6408

Hi,

I am using custom board based on AM335x.

on that I have connected 5 device on i2c bus(in Linux it is i2c-1 device).

but when i try to detect those devices (using 'i2cdetect' command in Linux), i got only 3 of them.

that two IO-Expanders(TCA6408ARGTR) doesn't get discovered, hence i can not communicate with it.

can anyone suggest what can i do to make it work.

Thanks.

0 Biser Gatchev-XID over 10 years ago

Hi,

Did you check for I2C address conflicts?

0 Dip Bhanvadiya over 10 years ago in reply to Biser Gatchev-XID

Hi,

yes I am sure that there are no conflicts.

we have set 0x20 and 0x21 for our IO-expanders, which is not used for any other devices.

and we do not get any devices on these addresses.

but we should get our devices there, which is not happening.

Thanks.

0 Biser Gatchev-XID over 10 years ago in reply to Dip Bhanvadiya

Addresses seem OK. What about the RESET input on the TCA6408?

0 Dip Bhanvadiya over 10 years ago in reply to Biser Gatchev-XID

Hi,

Thanks for reply.

The Reset pin is pulled up connected to 3.3V through 10K resistor.

and now, if we perform write operation on 0x20 address, it allows us to write and then read.

but if we do not perform write operation first, then device remains undetected.

means device only get detected after doing one write operation.

i don't understand why it is happening.

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