UG:309
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The “Clear” button allows the user to clear the PI33xx‑xx fault telemetry information.
The “ENA POL” button allows the user to read the EN polarity by left clicking on it. Changing the
polarity can be accomplished by entering the desired value in the dialog box and then left clicking the
“BURN” button. The Buck GUI will then instruct the user for the remaining steps. The burn function
is irreversible and requires careful consideration. For that reason, further details can be found in the
section “Configuration Programming”.
The “SYNC” button allows the user to read the SYNC polarity and delay settings by left clicking on it.
Changing the polarity can be accomplished by entering the desired value in the dialog box and then left
clicking the “BURN” button. The Buck GUI will then instruct the user for the remaining steps. The burn
function is irreversible and requires careful consideration. For that reason, further details can be found in
the section “Configuration Programming”.
The “KILL BIT2” button allows the user to prevent further changes to any programmed register value
when used in conjunction with the “BURN” button. The burn function is irreversible and requires careful
consideration. For that reason, further details can be found in the section “Configuration Programming”
The “MARGIN” button operates using volatile memory. Any changes made to this register are dynamic
and will change as soon as the command is sent. The user simply enters the value they wish to margin
and then clicks margin. Any value sent to this register will be lost as soon as power is removed. Note
that margining down 20% or more in one step may cause a VOUT_HI fault, which is a normal condition.
Fault Telemetry Command Structure
The PI33xx‑xx command structure is always a 2‑byte write and a 1‑byte read following the start
condition and the base address when using Buck GUI and the LinkM interface. The second data byte is
either 00h or additional data based on the command being sent. Figure 5 is an example of an I
2
C™ bus
command to read the fault register and it can be implemented using the Buck GUI by left‑clicking the
“FAULT” button. In a similar fashion, the actual fault register can be read from a generic I
2
C™ device
as shown in Figure 6 by sending the commands shown followed by stop bits. The I
2
C device used for
sending the command required a R/W bit for addressing so the address of 4Ch was sent as 98h.
In Figure 5, the address of 4Ch was sent followed by the first data byte. “4Ch” represents the base
address of the PI33xx‑xx as determined by ADR0 and ADR1. The first data byte is the address decode
of the internal register to be read (or written); in this case, read. “1Ah” is address of the fault register as
shown in Table 2.
Table 5
PI33xx‑xx margin
register assignments
Figure 5
Fault register read no fault
MRGN[3:0]
% V
OUT
1100
–20
1101
–15
1110
–10
1111
–5
0000
0
1000
5
1001
10
1010
15
1011
20
Summary of Contents for PI33 EVAL1 Series
Page 13: ...UG 309 Page 13 Figure 14 PI33xx xx SYNC 1000 timing Figure 15 PI33xx xx SYNC 1111 1 4MP ...
Page 14: ...UG 309 Page 14 Figure 16 PI33xx xx SYNC 1110 1 3MP Figure 17 PI33xx xx SYNC 1101 1 2MP ...
Page 15: ...UG 309 Page 15 Figure 18 PI33xx xx SYNC 1100 2 3MP Figure 19 PI33xx xx SYNC 1001 3 4MP ...
