I2C clock issue

Technical Support
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1

Hi,

I am working on a custom board using Wince 7 on a Colibri T20.

In order to use a capacitive touchscreen, I followed the steps to install the Multi touch driver:

But I struggle to communicate in I2C with my touchscreen device using the “multi touch hardware adaptation” software.

I try to set the clock to 400kHz but I observe a frequency between 37Khz and 41kHz by monitoring my I2C signals.

You can find below an extract of the code I used (derived from multi touch hardware adaptation software for fusion touchscreen using Toradex CE libraries):

image
image1464×827 128 KB

And here is the data I was able to observe:

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image1723×1050 36.3 KB

You can see in red my SDA signal and in red my scl signal.

Do you have any idea what might happen?

Best regards,
Romain FONCK

2

Hi @eiffonck ,

Are you sure that you are measuring on the right pins? What I2C port are you using? can you sent me the code with the exact i2c init sequence?
Also: on the HW side: what value of pull-up resistors are you using?

3

Hi,

I solved my issue by changing (but not deleting) the register key at: HKEY_LOCAL_MACHINE\init\Launch48

A dll named “RTCsync.dll” was previously used.

Best regards,

eiffonck