
MFR_SPECIFIC_10: BLOCK_READ (DAh)
The
BLOCK_READ
command
concatenates
the
DIAGNOSTIC_WORD with input and output telemetry infor-
mation (IIN, VOUT, VIN, PIN) as well as TEMPERATURE to
capture all of the operating information of the LM25066 in a
single SMBus transaction. The block is 12 bytes long with
telemetry information being sent out in the same manner as
if an individual READ_XXX command had been issued
(shown below). The contents of the block read register are
updated every clock cycle (85ns) as long as the SMBus in-
terface is idle. BLOCK_READ also guarantees that the VIN,
VOUT, IIN and PIN measurements are all time-aligned
whereas there is a chance they may not be if read with indi-
vidual PMBus commands.
The Block Read command is read via the PMBus block
read protocol.
TABLE 31. BLOCK_READ Register Format
Byte Count (always 12)
(1 byte)
DIAGNOSTIC_WORD
(1 Word)
IIN_BLOCK
(1 Word)
VOUT_BLOCK
(1 Word)
VIN_BLOCK
(1 Word)
PIN_BLOCK
(1 Word)
TEMP_BLOCK
(1 Word)
MFR_SPECIFIC_11: SAMPLES_FOR_AVG (DBh)
The SAMPLES_FOR_AVERAGE is a manufacturer specific
command for setting the number of samples used in comput-
ing the average values for IIN, VIN, VOUT, PIN. The decimal
equivalent of the AVGN nibble is the power of 2 samples (e.g.
AVGN=12 equates to 4096 samples used in computing the
average). The LM25066 supports average numbers of 1, 2,
4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096. The
SAMPLES_FOR_AVG number applies to average values of
IIN, VIN, VOUT, PIN simultaneously. The LM25066 uses sim-
ple averaging. This is accomplished by summing consecutive
results up to the number programmed, then dividing by the
number of samples. Averaging is calculated according to the
following sequence:
Y = (X
(N) + X(N-1) + ... + X(0)) / 2
AVGN
When the averaging has reached the end of a sequence (for
example, 4096 samples are averaged), then a whole new se-
quence begins that will require the same number of samples
(in this example, 4096) to be taken before the new average is
ready.
TABLE 32. SAMPLES_FOR_AVG Register
AVGN
N=2N averages
Averaging/Register
Update Period (ms)
0000
1
0001
2
0010
4
0011
8
0100
16
0101
32
0110
64
0111
128
1000
256
AVGN
N=2N averages
Averaging/Register
Update Period (ms)
1001
512
1010
1024
1011
2048
1100
4096
Note that a change in the SAMPLES_FOR_AVG register will
not be reflected in the average telemetry measurements until
the present averaging interval has completed. The default
setting for AVGN is 0000 and therefore the average telemetry
will mirror the instantaneous telemetry until a value higher
than zero is programmed.
The SAMPLES_FOR_AVG register is accessed via the PM-
Bus read / write byte protocol.
TABLE 33. SAMPLES_FOR_AVG Register
Value
Meaning
Default
0h – 0Ch
Exponent (AVGN)
for number of
samples to
average over
00h
MFR_SPECIFIC_12: READ_AVG_VIN (DCh)
The READ_AVG_VIN command will report the 12-bit ADC
measured input average voltage. If the data is not ready, the
returned value will be the previous averaged data. However,
if there is no previously averaged data, the default value
(0000h) will be returned. This data is read with the PMBus
Read Word protocol. This register should use the coefficients
shown in the Telemetry and Warning Conversion Coefficients
Table.
TABLE 34. READ_AVG_VIN Register
Value
Meaning
Default
0h – 0FFFh
Average of
measured values
for input voltage
0000h
MFR_SPECIFIC_13: READ_AVG_VOUT (DDh)
The READ_AVG_VOUT command will report the 12-bit ADC
measured average output voltage. The returned value will be
the default value (0000h) or previous data when the average
data is not ready. This data is read with the PMBus Read
Word protocol. This register should use the coefficients
shown in the Telemetry and Warning Conversion Coefficients
Table.
TABLE 35. READ_AVG_VOUT Register
Value
Meaning
Default
0h – 0FFFh
Average of
measured values
for output voltage
0000h
MFR_SPECIFIC_14: READ_AVG_IIN (DEh)
The READ AVG_IIN command will report the 12-bit ADC
measured current sense average voltage. The returned value
will be the default value (0000h) or previous data when the
average data is not ready. This data is read with the PMBus
Read Word protocol. This register should use the coefficients
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LM25066