Vicor PI33XX-2X I2C Digital Interface Guide - Manual (Page 19)

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PI33XX-2X I
2
C Digital Interface Guide
Configuration Example - Enable Polarity
Figure 25 shows the complete procedure for changing the enable polarity along with the I
2
C bus capture of all of
the commands required to make the changes using Picor Buck GUI or some other generic software. Since the
enable polarity is not changed until AFTER the burn is completed, always use the default polarity of the signal
before the burn process to enable and disable the target PI33XX-2X. It should be pointed out that the SYN[3:0]
register had already been programmed to “0010” on the PI33XX-2X target prior to the enable polarity change.
Note that the first two bus transactions occur when the target PI33XX-2X is enabled and the final transaction
occurs when it is disabled. Failure to follow this exact sequence will prevent successful storage of the desired
configuration settings. If an error message occurs or the incorrect results are obtained, refer to the section titled
“Error Messages” for more information.
Figure 25 - Changing ENA_POL Register to “1” With SYN[3:0] Programmed to “0010”