Digital Discovery I2C Clock Stretching

[DavidLee1997]

Good Afternoon!

I am trying to use the Digital Discovery as an I2C master with clock stretching enabled.  The device I am talking to will hold SCL low while it processes an interrupt, and release SCL when it is ready to receive again.  I am running into an issue where the device will hold SCL low for about 12s.  During this time, the LabVIEW function call has already closed even though the required data has not been transmitted/received.

How long will the Digital Discovery wait for the clock/data if clock stretching is enabled?

Thank you!

Respectfully,

David Johnson

[attila]

Hi @DavidLee1997

https://forum.digilentinc.com/topic/8908-waveforms-beta-download/

[attila]

Hi @DavidLee1997

dwf.h

DWFAPI int FDwfDigitalI2cTimeoutSet(HDWF hdwf, double sec);
 

[attila]

Hi @DavidLee1997

timeout = normal-i2c-transfer-time + ( 25ms X number-of-bytes) + 1sec

The next SDK version will add timeout option.

[DavidLee1997]

@attila Thank you!

I am installing now, and will be testing this afternoon.

Respectfully,

David Johnson

[DavidLee1997]

@attila Will there be a new .h file?  I'm trying to add the function to the LabVIEW library.

Thank you!

[DavidLee1997]

@attila

This is exactly what I needed!  Thank you!  I have already run the test sequence and it appears that the issue has been fully resolved.

Respectfully,

David Johnson