I2C Start Condition - Implementing I2C Communication Protocol in LabVIEW FPGA

[johnsoja]

I'm attempting to use the I2C FPGA code shown in the article "Implementing I2C Communication Protocol in LabVIEW FPGA" located at https://forums.ni.com/t5/Example-Code/I2C-Bus-Communication-Example-Using-LabVIEW-FPGA/ta-p/3996143 on a PXI-7852R.  However, the start condition logic appears to be incorrect as shown.  The I2C protocol dictates that the start condition is set by high to low transition on the Data line while the Clk is high.  However, Figure 12 of this article appears to show that the SDA line is held high for the start condition with no transition low.  It seems to me that the second sequence frame should set SDA to "False" instead of "True".  Is this an error in the document or am I missing something?

[BoKnows]

It looks like an error.  Otherwise, it wouldn't make sense for the second frame of the sequence to set the SDA to True.  It was already set to True in the first frame.

[mita1234]

We too have the same query.. Please help us get enlightened on this. We still are figuring out if its a bug or that we have failed to understand some missing link in here.

[Trevor.H]

Hi there,

It seems the link in the original post is broken, so I can't see the context.  Was it something similar to this?  Additionally, it may be worth making a new post, as this one is a bit older, and may not get the same visibility.

[wiebe@CARYA]

No white papers called "Implementing I2C Communication Protocol in LabVIEW FPGA" anymore, but the top two results for "Implementing I2C Communication Protocol in LabVIEW FPGA" search for white papers seems relevant\related.

[Trevor.H]

I'm going to assume https://www.ni.com/en/shop/electronic-test-instrumentation/add-ons-for-electronic-test-and-instrumen... on Figure #10 is the closest comparison to the original post.  While both the frames are setting enable to true, it is worth noting the first sets SDA, and the second sets SCL. After this original assertion, figure #11 shows the data transfer. 

If this is not a comparable situation to the original post, please let me know!