MCP9804 Microchip Technology, MCP9804 Datasheet - Page 24

• Manufacturer Part Number: MCP9804
• Description: Accuracy Digital Temperature Sensor
• Manufacturer: Microchip Technology

MCP9804
5.1.3
The MCP9804 uses a band gap temperature sensor
circuit to output analog voltage proportional to absolute
temperature. An internal ΔΣ ADC is used to convert the
analog voltage to a digital word. The digital word is
loaded to a 16-bit read-only Ambient Temperature
register
two’s complement format.
The T
Therefore, the user can access the register while, in the
background, the MCP9804 performs an analog-to-
digital conversion. The temperature data from the ΔΣ
ADC is loaded in parallel to the T
refresh rate.
REGISTER 5-4:
DS22203A-page 24
bit 15
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 15
bit 14
bit 13
bit 12
bit 11-0
T
A
Note 1: Bits 15, 14 and 13 are not affected by the status of the Alert output configuration (bits 5 to 0 of CONFIG)
vs. T
2
R-0
R-0
A
3
register bits (bits 12 thru 0) are double-buffered.
°C
(T
2: Bits 2, 1, and 0 may remain clear '0' depending on the status of the resolution register
CRIT
A
AMBIENT TEMPERATURE
REGISTER (T
)
(Register
The Power-up default is 0.25°C/bit, bits 1 and 0 remain clear '0'.
that contains 13-bit temperature data in
T
T
0 = T
1 = T
T
0
1 =
T
0 =
1 =
SIGN Bit:
0 =
1 =
Ambient Temperature (T
12-bit Ambient Temperature data in two’s complement format.
A
A
A
A
=
vs. T
vs. T
vs. T
vs. T
2
R-0
R-0
2
T
T
T
T
T
T
5-2).
AMBIENT TEMPERATURE REGISTER (T
°C
A
A
A
A
A
A
A
A
UPPER
CRIT
UPPER
LOWER
< T
≥ T
≤ T
> T
≥ T
< T
≥ 0°C
< 0°C
A
CRIT
CRIT
UPPER
UPPER
LOWER
LOWER
(Note 1)
)
(Note 1)
(Note 1)
W = Writable bit
‘1’ = Bit is set
T
A
vs. T
A
Bit:
2
register at t
R-0
R-0
1
Bit:
Bit:
°C
LOWER
A
) Bits:
CONV
(Note 2)
SIGN
2
R-0
R-0
0
°C
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
In addition, the T
and 13) to reflect the Alert pin state. This allows the
user to identify the cause of the Alert output trigger (see
Section 5.2.3); bit 15 is set to ‘1’ if T
equal to T
T
The T
conditions are described in
UPPER
2
2
R-0
R-0
-1
7
°C
°C
A
A
and bit 13 is set to ‘1’ if T
) → ADDRESS
CRIT
register bit assignment and boundary
, bit 14 is set to ‘1’ if T
2
2
A
R-0
R-0
-2
6
register uses three bits (bits 15, 14
°C
°C
© 2009 Microchip Technology Inc.
‘0000 0101’b
Register
x = Bit is unknown
2
2
R-0
R-0
A
-3
5
is less than T
°C
°C
A
5-4.
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is greater than or
A
(Register
is greater than
(NOTE 1)
2
2
R-0
R-0
-4
4
LOWER
°C
°C
5-7).
bit 8
bit 0
.