Datasheet

DS75
9 of 14
CONFIGURATION REGISTER
The configuration register allows the user to program various DS75 options such as conversion
resolution, thermostat fault tolerance, thermostat polarity, thermostat operating mode, and shutdown
mode. The configuration register is arranged as shown in Figure 5 and detailed descriptions of each bit
are provided in Table 4. The user has read/write access to all bits in the configuration register except the
MSb, which is a reserved read-only bit. The entire register is volatile, and thus powers–up in its default
state.
Figure 5. CONFIGURATION REGISTER
MSb
b
it 6
b
it 5
b
it 4
b
it 3
b
it 2
b
it 1 LSb
0 R1 R0 F1 F0 POL TM SD
Table 4. CONFIGURATION REGISTER BIT DESCRIPTIONS
BIT NAME FUNCTIONAL DESCRIPTION
0
Reserved
Power-up state = 0
The master can write to this bit, but it will always read out as a 0.
R1
Conversion Resolution Bit 1
Power-up state = 0
Sets conversion resolution (see Table 5)
R0
Conversion Resolution Bit 0
Power-up state = 0
Sets conversion resolution (see Table 5)
F1
Thermostat Fault Tolerance Bit 1
Power-up state = 0
Sets the thermostat fault tolerance (see Table 6).
F0
Thermostat Fault Tolerance Bit 0
Power-up state = 0
Sets the thermostat fault tolerance (see Table 6).
POL
Thermostat Output (O.S.) Polarity
Power-up state = 0
POL = 0 — O.S. is active low.
POL = 1 — O.S. is active high.
TM
Thermostat Operating Mode
Power-up state = 0
TM = 0 — Comparator mode.
TM = 1 — Interrupt mode.
See the OPERATION–Thermostat section for a detailed description
of these modes.
SD
Shutdown
Power-up state = 0
SD = 0 — Active conversion and thermostat operation.
SD = 1 — Shutdown mode.
See the SHUTDOWN MODE section for a detailed description of
this mode.
Table 5. RESOLUTION CONFIGURATION
R1 R0 THERMOMETER
RESOLUTION
MAX CONVERSION
TIME
0 0 9–bit 150 ms
0 1 10–bit 300 ms
1 0 11–bit 600 ms
1 1 12–bit 1200 ms