Vicor PI33XX-2X I2C Digital Interface Guide - Manual (Page 16)

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PI33XX-2X I
2
C Digital Interface Guide
Programming Initial Conditions
Once the user has selected the configuration for the timing register, the burn process can be initiated. To begin
this process, the user must be ready to be able to enable and disable the PI33XX-2X, since this is required to enter
the burn mode and actually burn the bits. The initial conditions to begin the burn process are as follows:
1. Proper input voltage should be applied to the target PI33XX-2X.
2. The unit can be either enabled and producing output voltage or disabled with the output voltage at zero. The
preferred method is disabled since in some cases multiple units may depend on proper phase delay for best
performance. The user must adhere to the instructions from the GUI to ensure proper burn results.
The burn process consumes power from the internal bias for the controller, so only a single bit can be burned at a
time. Picor Buck GUI takes care of this for the user and will generate the appropriate number of bus commands to
ensure each bit is burned correctly. Users that write their own software or operate from a different GUI will need
to consider this. In addition, power should not be removed from the PI33XX-2X during the burn process. The Picor
Buck GUI will prompt the user when to enable and disable the target. Enabling and disabling is done using the EN
pin. One important note to consider is that if the enable polarity has been changed already due to a separate
operation, the new enable polarity must be used when enabling and disabling. The procedure along with the Picor
Buck GUI commands, for changing the SYN[3:0] register so that the synchronization polarity is falling edge and the
delay is 3/4 MP is as follows: