71m6543h-igtr/f Maxim Integrated Products, Inc., 71m6543h-igtr/f Datasheet - Page 53

• Manufacturer Part Number: 71m6543h-igtr/f
• Description: Energy Meter Ic
• Manufacturer: Maxim Integrated Products, Inc.

Refer to
RTC_P[16:0] and RTC_Q[1:0]. The 8-bit values loaded in to NV RAM must be scaled correctly to produce
limiter ensures that the resulting look-up address is in the 6-bit plus sign range of -64 to +63 (decimal).
The 8-bit NV RAM content pointed to by the address is added as a 2’s complement value to 0x40000,
the nominal value of 4*RTC_P[16:0] + RTC_Q[1:0].
rate adjustments that are consistent with the equations given in
and RTC_Q[1:0]. Note that the sum of the looked-up 8-bit 2’s complement value and 0x40000 form a 19-
bit value, which is equal to 4*RTC_P[16:0] + RTC_Q[1:0], as shown in
Temperature Compensation is automatically loaded into the RTC_P[16:0] and RTC_Q[1:0] locations after
each look-up and summation operation.
The 128 NV RAM locations are organized in 2’s complement format as shown in
above, the STEMP[10:0] digital temperature values are scaled such that the corresponding NV RAM
addresses are equal to STEMP[10:0]/4 (limited in the range of -64 to +63). See
Temperature Sensor
STEMP[10:0] reading.
The above equation is used to calculate the two temperature columns in
the rightmost column). The second column uses the full 11-bit values of STEMP[10:0], while the values in
the rightmost column are calculated using the post-limiter (6+S) values multiplied by 4. Since each look-
up table address step corresponds to a 4 x 0.327 °C temperature step, two is added to the post-limiter
6+S value after multiplying by 4 to calculate the temperature values in the rightmost column. This method
ensures that the compensation data is loaded into the look-up table in a manner that minimizes
quantization error.
values of STEMP[10:0] outside the -256 to +255 range are not shown in this table. The limiter output is
confined to the range of -64 to +63, which is directly the desired address of the 128-byte look-up table.
The rightmost column gives the nominal temperature corresponding to each address cell in the 128-byte
compensation table.
v1.0
2.5.4.3 RTC Rate Control
STEMP
10+S
STEMP[10:0]
>>2
(decimal)
Table 44
(10+S)
-256
-255
-254
-253
…
on page
-4
-3
-2
-1
0
1
2
8+S
Figure 13: Automatic Temperature Compensation
LIMIT
-256
© 2008–2011 Teridian Semiconductor Corporation
shows the numerical values corresponding to each node in
54
-64
(Equation)
Temp (
for the equations to calculate temperature in degrees °C from the
-61.71
-61.39
-61.06
-60.73
20.69
21.02
21.35
21.67
22.00
22.33
22.65
-64
Table 44: NV RAM Table Structure
for information on the rate adjustments performed by registers
63
…
o
C)
63
255
STEMP[10:0]>>2
(decimal)
6+S
(8+S)
-64
…
-1
0
ADDR
Look Up
RAM
Q
2.5.4.3 RTC Rate Control
Limiter Output
7+S
(decimal)
(6+S)
-64
0x40000
…
-1
19
Figure 13.
0
Σ
Table 44
19
2.5.5 71M6543F/H
4*RTC_P+RTC_Q
(LU Table)
Temp (
71M6543F/H Data Sheet
Table
The output of the
(the second column and
-61.06
21.35
22.65
…
o
C)
44. As mentioned
Figure
for RTC_P[16:0]
13. The
53