RV-3029 Datasheet, PDF (40/67 Pages) MICORO CRYSTAL SWITZERLAND – DTCXO Temperature Compensated Real Time Clock

Micro Crystal
DTCXO Temperature Compensated Real Time Clock / Calendar Module
RV-3029
5.2.2.SETTING THE FREQUENCY COMPENSATION PARAMETERS
In order to achieve best time accuracy, correct parameters have to be stored into the corresponding registers of the
EEPROM Control page.
Attention: these parameters are factory calibrated, it is recommended not to modify these register values.
XTAL Offset (address 31h…bits description)
Address
Function
Bit 7
31h
XTAL Offset
sign
Bit 6
64
Bit 5
32
Bit 4
16
Bit 3
8
Bit 2
4
Bit
7
6 to 0
Symbol
Sign
XTAL Offset
Value
0
1
0 to 121
Description
- Deviation (slower) of 32.768kHz frequency at T0
+ Deviation (faster) of 32.768kHz frequency at T0
Frequency Offset Compensation value
Bit 1
2
Bit 0
1
The register value “XTAL Offset” is used by the Frequency Compensation Unit “FCU” to compensate the initial
frequency deviation of the 32.768 kHz clock at the crystal’s turnover temperature “XTAL T₀”.
The required register value “XTAL Offset” is calculated as follow:
XTAL Offset = Xtal_OFFSET x 1.05
XTAL COEF Temperature Coefficient (address 32h…bits description)
Address
Function
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3 Bit 2
32h
XTAL Coef
128
64
32
16
8
4
Bit
7 to 0
Symbol
XTAL Coef¹⁾
Value
Description
0 to 255 Quadratic Coefficient of XTAL’s Temperature Drift
1) _{The factory programmed register value XTAL Coef may also contain thermometer error compensation.}
Bit 1
2
Bit 0
1
Reference
The register value “XTAL Coef” is used by the Frequency Compensation Unit “FCU” to compensate the frequency
deviation caused by 2^nd order temperature coefficient of the 32.768 kHz crystal (frequency drift vs temperature).
The required register value “XTAL Coef” is calculated as follow:
XTAL Coef = Xtal_{TEMPERATURE COEFFICIENT} x 4096 x 1.05
XTAL T0 Turnover Temperature (address 33h…bits description)
Address
Function
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3 Bit 2 Bit 1
Bit 0
33h
XTAL T0
x
x
32
16
8
4
2
1
Bit
7 to 6
5 to 0
Symbol
x
XTAL T0¹⁾
Value
-
4 to 67
Description
unused
XTAL’s Turnover Temperature in °C
Reference
1) _{The factory programmed register value XTAL T0 may also contain thermometer error compensation.}
The register value “XTAL T0” is used by the Frequency Compensation Unit “FCU” to compensate the frequency
deviation caused by the turnover temperature T0 of the 32.768 kHz crystal.
The required register value “XTAL T0” is calculated as follow:
XTAL T0 = Xtal_{TURNOVER TEMP T0} - 4
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