71M6521FE-IM/F Maxim Integrated Products, 71M6521FE-IM/F Datasheet - Page 65

• Manufacturer Part Number: 71M6521FE-IM/F
• Description: IC ENERGY METER 32K FLASH 68-QFN
• Manufacturer: Maxim Integrated Products

Specifications of 71M6521FE-IM/F

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

71M6521DE/DH/FE Data Sheet
The MPU Demo Code supplied with the Teridian Demo Kits has a direct interface for these coefficients and it directly
controls the RTC_DEC_SEC or RTC_INC_SEC registers. The Demo Code uses the coefficients in the form:
Note that the coefficients are scaled by 10, 100, and 1000 to provide more resolution. For our example case, the
coefficients would then become (after rounding):
Alternatively, the mains frequency may be used to stabilize or check the function of the RTC. For this purpose, the
CE provides a count of the zero crossings detected for the selected line voltage in the MAIN_EDGE_X address. This
count is equivalent to twice the line frequency, and can be used to synchronize and/or correct the RTC.
All digital input pins of the 71M6521DE/DH/FE are compatible with external 5 V devices. I/O pins configured as inputs
do not require current-limiting resistors when they are connected to external 5 V devices.
Rev 2
Y_CAL = 109, Y_CALC = 12, Y_CALC2 = 7
CORRECTION
32768.5
32768.4
32768.3
32768.2
32768.1
32767.9
32767.8
32767.7
32767.6
32767.5
(
32768
ppm
-50
)
=
Y
_
10
CAL
Figure 33: Crystal Compensation
Connecting 5 V Devices
+
-25
T
⋅
Y
_
100
CALC
crystal
curve fit
inverse curve
0
+
T
2
⋅
Y
_
1000
CALC
25
2
50
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