Datasheet

LTC3883/LTC3883-1
62
3883fa
For more information www.linear.com/LTC3883
APPLICATIONS INFORMATION
Figure 33. Example of a Command Write of VOUT_COMMAND
Command data buffering handles incoming PMBus writes
by storing the command data to the Write Command Data
Buffer and marking these commands for future process
-
ing. The internal processor runs in parallel and handles
the sometimes slower task of fetching, converting and
executing commands marked for processing.
Some computationally intensive commands (e.g., timing
parameters, temperatures, voltages and currents) have
// wait until bits 6, 5, and 4 of MFR_COMMON are all set
do
{
mfrCommonValue = PMBUS_READ_BYTE(0xEF);
partReady = (mfrCommonV
alue & 0x70) == 0x70;
}while(!partReady)
Figure 31. LTpowerPlay Screen Shot
DECODER
CMD
INTERNAL
PROCESSOR
WRITE COMMAND
DATA BUFFER
PAGE
CMDS
0x00
0x21
0xFD
3883 F32
x1
•
•
•
•
•
•
MFR_RESET
VOUT_COMMAND
S
CALCULATIONS
PENDING
PMBus
WRITE
R
FETCH,
CONVERT
DATA
AND
EXECUTE
DATA
MUX
Figure 32. Write Command Data Processing
internal processor execution times that may be long relative
to PMBus timing. If the part is busy processing a command,
and new command(s) arrive, execution may be delayed
or processed in a different order than received. The part
indicates when internal calculations are in process via bit5
of MFR_COMMON (‘calculations not pending’). When the
part is busy calculating, bit 5 is cleared. When this bit is
set, the part is ready for another command. An example
polling loop is provided in Figure 33 which ensures that
commands are processed in order while simplifying error
handling routines.