TWI with TCA6424A

RE: TWI with TCA6424A

Michal — Fri, 16 Mar 2018 13:42:11 GMT

I was using default gpios as in example. I think it was 27 for SCL and 26 for SDA. I will try modifying hardware setup and post here any results later. Thanks for help.

RE: TWI with TCA6424A

Jakub Rzeszutko — Fri, 16 Mar 2018 12:43:54 GMT

Hi,

I do not see any obvious inconsistency, our chip and TCA6424A are supporting 7 bit addressing.

Did you connect TCA6424A to our DK? Which PINs did you use?

RE: TWI with TCA6424A

Michal — Fri, 16 Mar 2018 11:52:12 GMT

Hi Kuba,

Can you confirm that is not possible that twi is incompatible with IC that communicates over i2c? Thanks

RE: TWI with TCA6424A

Jakub Rzeszutko — Fri, 16 Mar 2018 11:15:46 GMT

Hi,

TWI scanner is the best what you can use to check I2C communication. If it does not work I am affraid you need a logic analyzer or oscyloscope.

RE: TWI with TCA6424A

Sylvain — Fri, 16 Mar 2018 10:17:12 GMT

Sorry, I badly read your first post. In fact, if you just want to know the adress of your devices the I2C scanner is appropriate.

The external pull-up aren't obligatory since the nRF implement internal pull up.

So, the best way to fix your problem is to found an oscilloscope and check your hardware configuration.

RE: TWI with TCA6424A

Michal — Fri, 16 Mar 2018 10:06:36 GMT

Why it should be better or easer? Twi sensor example expects specific hardware on specific address while twi_scanner just tries to read from every single possible i2c address and checks if any responds with ACK. That looks like more reliable check. I can check with twi_sensor but I dont expect better results.

RE: TWI with TCA6424A

Sylvain — Fri, 16 Mar 2018 09:53:01 GMT

Seems better and easier to use the twi_sensor example.

Try and let me know ...

RE: TWI with TCA6424A

Michal — Fri, 16 Mar 2018 09:44:38 GMT

Thanks. As I mentioned I am using twi_scanner sample application from nordic SDK. I will have logic analyzer soon but for now I dont have any sophisticated tools. Although as I tak unmodified example from SDK 14.2 I expect that signals are correct. I also tried other sdk - 11, 12, 12.3 but there were no difference.

RE: TWI with TCA6424A

Sylvain — Fri, 16 Mar 2018 09:38:21 GMT

Hi Michal,

if you have an oscilloscope try to check your SCK and SDA lines to be sure that you have the right signal.

Can you post your main code ?

Sylvain.