Vicor PI33XX-2X I2C Digital Interface Guide - Manual (Page 10)

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PI33XX-2X I
2
C Digital Interface Guide
Figure 7 shows the bus capture of the instructions sent after clicking on the “Clear” button using Picor Buck GUI.
Here there are four I
2
C messages sent. The address field shows the address of the PI33XX-2X and then there are
two bytes of data. The first byte is the address of the FREG_CLR register. The second byte is the data. The next
message is a read of the address. This read is performed by the LinkM and is not needed to make the transaction
complete. This command could be sent by a generic I
2
C interface as:
START WRITE 98h 2 Bytes 1Bh,00h followed by STOP
START WRITE 98h 2 bytes 1Ah,00 followed by STOP
START READ 99h 1 Byte followed by STOP
The data returned should be the same as seen previously. In the event an actual fault occurs, the Picor Buck GUI
will indicate the fault graphically as a result of decoding the fault register. Figure 8 shows the I
2
C bus capture of the
event, while the Picor Buck GUI decodes the fault and gives a visual indication as shown in Figure 9.
Figure 8 - I
2
C Bus Capture Input Under Voltage Fault Register Read Using Picor Buck GUI and Linkm
Figure 10 shows several more common faults displayed by the Picor Buck GUI along with the corresponding I
2 C bus
capture of each event. The first fault SLOW_IL, the second fault is VOUT_HI and the third fault is OVLO.
Figure 11 shows the I
2
C bus capture of dynamically margining the PI33XX-2X output voltage down -20% by entering
“1100” in the “MARGIN” dialog box and clicking the “MARGIN” button. Note that “0Ch” is sent in the second data
byte, which is the margin value.