DS1631-DS1731 DALLAS [Dallas Semiconductor], DS1631-DS1731 Datasheet - Page 8

• Manufacturer Part Number: DS1631-DS1731
• Description: High-Precision Digital Thermometer and Thermostat
• Manufacturer: DALLAS [Dallas Semiconductor]

and Access TL commands. When making changes to the T
stopped using the Stop Convert T command if the device is in continuous conversion mode. Note that if
the thermostat function is not used, the T
Another thermostat feature is the temperature high and low flags (THF and TLF) in the configuration
register. These bits provide a record of whether the temperature has been greater than T
at anytime since the device was powered up. These bits power up as 0s, and if the temperature ever
exceeds the T
the TLF bit is set to 1. Once THF and/or TLF has been set, it remains set until overwritten with a 0 by the
user or until the power is cycled.
DS1631A STAND-ALONE THERMOSTAT OPERATION
Since the DS1631A automatically begins taking temperature measurements at power-up, it can function
as a standalone thermostat (i.e., it can provide thermostatic operation without microcontroller
communication). For standalone operation, the NV T
the configuration register should be programmed to the desired values prior to installation. Since the
default conversion resolution at power-up is 12 bits (R1 = 1 and R0 = 1 in the configuration register), the
conversion resolution is always 12 bits during standalone thermostat operation.
Figure 5. THERMOSTAT OUTPUT OPERATION
CONFIGURATION REGISTER
The configuration register allows the user to program various DS1631 options such as conversion
resolution, T
status, EEPROM activity, and thermostat activity. The configuration register is arranged as shown in
Figure 6 and detailed descriptions of each bit are provided in Table 5. This register can be read from and
written to using the Access Config command. When writing to the configuration register, conversions
should first be stopped using the Stop Convert T command if the device is in continuous conversion
mode. Note that the POL and 1SHOT bits are stored in EEPROM so they can be programmed prior to
installation is desired. All other configuration register bits are SRAM and power up in the state shown in
Table 5.
Figure 6. CONFIGURATION REGISTER
OUT
H
register value, the THF bit is set to 1, or if the temperature ever falls below the T
polarity, and operating mode. It also provides information to the user about conversion
*NV (EEPROM)
DONE
LOGIC 1
LOGIC 0
MSb
THF
bit 6
TLF
bit 5
T
POL = 1 (T
H
L
and T
NVB
bit 4
L
T
OUT
registers can be used as general-purpose NV memory.
OUT
8 of 14
IS ACTIVE HIGH)
H
bit 3
R1
and T
H
T
and T
H
L
bit 2
registers and the POL and 1SHOT bits in
R0
L
registers, conversions should first be
POL* 1SHOT*
TEMP
bit 1
LSb
DS1631/DS1631A/DS1731
H
or less than T
L
value,
L