NCT214
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9
Table 7. TEMPERATURE DATA FORMAT
(TEMPERATURE HIGH BYTE)
Temperature
Binary
Offset Binary
(Note 1)
55癈
0 000 0000
(Note 2)
0 000 1001
0癈
0 000 0000
0 100 0000
+1癈
0 000 0001
0 100 0001
+10癈
0 000 1010
0 100 1010
+25癈
0 001 1001
0 101 1001
+50癈
0 011 0010
0 111 0010
+75癈
0 100 1011
1 000 1011
+100癈
0 110 0100
1 010 0100
+125癈
0 111 1101
1 011 1101
+127癈
0 111 1111
1 011 1111
+150癈
0 111 1111
(Note 3)
1 101 0110
1.  Offset binary scale temperature values are offset by 64癈.
2.  Binary scale temperature measurement returns 0癈 for all
temperatures < 0癈.
3.  Binary scale temperature measurement returns 127癈 for all
temperatures > 127癈.
The user can switch between measurement ranges at any
time. Switching the range likewise switches the data format.
The next temperature result following the switching is
reported back to the register in the new format. However, the
contents of the limit registers do not change. It is up to the
user to ensure that when the data format changes, the limit
registers are reprogrammed as necessary. More information
on this is found in the Limit Registers section.
NCT214 Registers
The NCT214 contains 22, 8-bit registers in total. These
registers store the results of remote and local temperature
measurements, high and low temperature limits, and
configure and control the device. See the Address Pointer
Register section through the Consecutive ALERT
Register
section of this data sheet for more information on the
NCT214 registers. Additional details are shown in Table 8
through Table 12. The entire register map is available in
Table 13.
Address Pointer Register
The address pointer register itself does not have, nor does
it require, an address because the first byte of every write
operation is automatically written to this register. The data
in this first byte always contains the address of another
register on the NCT214 that is stored in the address pointer
register. It is to this register address that the second byte of
a write operation is written, or to which a subsequent read
operation is performed.
The power-on default value of the address pointer register
is 0x00. Therefore, if a read operation is performed
immediately after power-on, without first writing to the
address pointer, the value of the local temperature is returned
because its register address is 0x00.
Temperature Value Registers
The NCT214 has three registers to store the results of local
and remote temperature measurements. These registers can
only be written to by the ADC and can be read by the user
over the SMBus/I
2
C. The local temperature value register is
at Address 0x00.
The external temperature value high byte register is at
Address 0x01, with the low byte register at Address 0x10.
The power-on default for all three registers is 0x00.
Configuration Register
The configuration register is Address 0x03 at read and
Address 0x09 at write. Its power-on default is 0x00. Only
four bits of the configuration register are used. Bit 0, Bit 1,
Bit 3, and Bit 4 are reserved; the user does not write to them.
Bit 7 of the configuration register masks the ALERT
output. If Bit 7 is 0, the ALERT
output is enabled. This is the
power-on default. If Bit 7 is set to 1, the ALERT
output is
disabled. This applies only if Pin 6 is configured as ALERT
.
If Pin 6 is configured as THERM2
, then the value of Bit 7
has no effect.
If Bit 6 is set to 0, which is power-on default, the device
is in operating mode with ADC converting. If Bit 6 is set to
1, the device is in standby mode and the ADC does not
convert. The SMBus does, however, remain active in
standby mode; therefore, values can be read from or written
to the NCT214 via the SMBus. The ALERT
and THERM
outputs are also active in standby mode. Changes made to
the registers in standby mode that affect the THERM
or
ALERT
outputs cause these signals to be updated.
Bit 5 determines the configuration of Pin 6 on the
NCT214. If Bit 5 is 0 (default), then Pin 6 is configured as
an ALERT
output. If Bit 5 is 1, then Pin 6 is configured as
a THERM2
output. Bit 7, the ALERT
mask bit, is only
active when Pin 6 is configured as an ALERT
output. If
Pin 6 is set up as a THERM2
output, then Bit 7 has no effect.
Bit 2 sets the temperature measurement range. If Bit 2 is
0 (default value), the temperature measurement range is set
between 0癈 to +127癈. Setting Bit 2 to 1 sets the
measurement range to the extended temperature range
(64癈 to +191癈).
Table 8. CONFIGURATION REGISTER BIT
ASSIGNMENTS
Bit
Name
Function
Power-On
Default
7
MASK1
0 = ALERT
Enabled
1 = ALERT
Masked
0
6
RUN/STOP
0 = Run
1 = Standby
0
5
ALERT
/
THERM2
0 = ALERT
1 = THERM2
0
4, 3
Reserved
0
2
Temperature
Range Select
0 = 0癈 to 127癈
1 = Extended Range
0
1, 0
Reserved
0