Averagecurrent register (0bh), Maxmincurrent register (1ch), Cgain register 2eh/coff register (2fh) – Rainbow Electronics MAX17047 User Manual
Page 37: Figure 52. averagecurrent register forma, Figure 53. maxmincurrent register format
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MAX17047
ModelGauge m3 Fuel Gauge
AverageCurrent Register (0Bh)
The AverageCurrent register reports an average of
current-register readings over a configurable 0.7s to
6.4h time period. See the FilterCFG register descrip-
tion for details on setting the time filter. The resulting
average is placed in the AverageCurrent register with
an LSb value of 1.5625FV/R
SENSE
. The first Current
register reading after device power-up sets the start-
ing point of the AverageCurrent filter. The last value
of the AverageCurrent register is maintained when the
device enters shutdown mode.
AverageCurrent register format.
MaxMinCurrent Register (1Ch)
The MaxMinCurrent register maintains the maximum and
minimum Current register values since the last fuel gauge
reset or until cleared by host software. Each time the
Current register updates, it is compared against these
values. If the reading is larger than the maximum or less
than the minimum, the corresponding value is replaced
with the new reading. At power-up, the MaxCurrent value
is set to 80h (the minimum) and the MinCurrent value is
set to 7Fh (the maximum). Therefore, both values are
changed to the Current register reading after the first
update. Host software can reset this register by writing it
to its power-up value of 807Fh. The maximum and mini-
mum voltages are each stored as two’s-complement 8-bit
values with 0.4mV/R
SENSE
resolution.
shows
the MaxMinCurrent register format.
CGAIN Register (2Eh)/COFF Register (2Fh)
The CGAIN and COFF registers adjust the gain and off-
set of the current measurement result. The current mea-
surement A/D is factory trimmed to data-sheet accuracy
without the need for the user to make further adjustments.
The default power-up settings for CGAIN and COFF
apply no adjustments to the Current register reading. For
specific application requirements, the CGAIN and COFF
registers can be used to adjust readings as follows:
Current Register = Current A/D Reading O
(CGAIN Register/16384) + (2 O COFF Register)
Figure 53. MaxMinCurrent Register Format (Output)
Figure 52. AverageCurrent Register Format (Output)
Figure 53
MSB—ADDRESS 1Ch
LSB—ADDRESS 1Ch
S
MAX
6
MAX
5
MAX
4
MAX
3
MAX
2
MAX
1
MAX
0
S
MIN
6
MIN
5
MIN
4
MIN
3
MIN
2
MIN
1
MIN
0
MSb
LSb
MSb
LSb
UNITS: 0.4mV/R
SENSE
Figure 52
MSB—ADDRESS 0Bh
LSB—ADDRESS 0BH
S
2
14
2
13
2
12
2
11
2
10
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
MSb
LSb
MSb
LSb
UNITS: 1.5625FV/R
SENSE