RV-3029 Datasheet, PDF (39/67 Pages) MICORO CRYSTAL SWITZERLAND – DTCXO Temperature Compensated Real Time Clock

Micro Crystal
DTCXO Temperature Compensated Real Time Clock / Calendar Module
RV-3029
5.2.1.THERMOMETER AND TEMPERATURE VALUE
The function of the Thermometer is controlled by “ThP” and “ThE” (bit 0 & bit 1 in the register EEPROM Control).
Register EEPROM Control Thermometer Control (address 30h…bits description)
Address
Function
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3 Bit 2
30h
EEPROM Control
R80k
R20k
R5k
R1k
FD1
FD0
Bit
Symbol
1
ThE
0
ThP
Value
0
1
0
1
Description
Disable Thermometer
Enable Thermometer
Thermometer scanning interval: 1 second
Thermometer scanning interval: 16 seconds
Bit 1
ThE
Bit 0
ThP
The measured temperature value is stored in the register “Temperature” at address 20h.
The measured temperature is binary coded ranging from -60°C (=0d) to +190°C (=250d).
Example: Temperature of 0°C corresponding to a content of = 60d.
The thermometer has a resolution of 1°C per LSB; the typical accuracy is +/-4°C within the temperature range
-40°C to +125°C. The Thermometer is automatically disabled if status bit “Vlow1” is set = “1”, the result of the last
temperature measurement is frozen in register “Temperature” and the frequency compensation continues working
with this last temperature reading.
The actual temperature value can be read from register “Temperature” at address 20h. The Thermometer has to be
disabled by ThE = “0” to externally write a temperature value into the register “Temperature” at address 20h.
Temperature Value (address 20h…bits description)
Address
Function
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3 Bit 2 Bit 1
20h
Temperature
128
64
32
16
8
4
2
These bits hold the Temperature Value coded in binary format
Temperature
-60°C
-59°C
0°C
Value hex
00h
01h
3Ch
Bit 7
0
0
0
Bit 6
0
0
0
Bit 5
0
0
1
Bit 4
0
0
1
Bit 3
0
0
1
Bit 2
0
0
1
Bit 1
0
0
0
194°C
FEh
195°C
FFh
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Bit 0
1
Bit 0
0
1
0
0
1
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