MCP9800 View Datasheet(PDF) - Microchip Technology
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MCP9800 Datasheet PDF : 42 Pages
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MCP9800/1/2/3
5.3.1 AMBIENT TEMPERATURE
REGISTER (TA)
The MCP9800/1/2/3 has a 16-bit read-only Ambient
Temperature register that contains 9-bit to 12-bit
temperature data. (0.5°C to 0.0625°C resolutions,
respectively). This data is formatted in two’s
complement. The bit assignments, as well as the
corresponding resolution, is shown in the register
assignment below.
The refresh rate of this register depends on the
selected ADC resolution. It takes 30 ms (typical) for
9-bit data and 240 ms (typical) for 12-bit data. Since
this register is double-buffered, the user can read the
register while the MCP9800/1/2/3 performs
Analog-to-Digital conversion in the background. The
decimal code to ambient temperature conversion is
shown in Equation 5-2:
EQUATION 5-2:
Where:
TA = Code 2–4
TA = Ambient Temperature (°C)
Code = MCP9800 output in decimal
REGISTER 5-2:
Upper Half:
R-0
Sign
bit 15
AMBIENT TEMPERATURE REGISTER (TA) – ADDRESS <0000 0000>b
R-0
26 °C
R-0
25 °C
R-0
24 °C
R-0
23 °C
R-0
22 °C
R-0
21 °C
R-0
20 °C
bit 8
Lower Half:
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
2-1 °C/bit
2-2 °C
2-3 °C
2-4 °C
0
0
0
0
bit 7
bit 0
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
Note 1: When the 0.5°C, 0.25°C or 0.125°C resolutions are selected, bit 6, bit 7 or bit 8 will remain clear <0>,
respectively.
DS21909D-page 16
2010 Microchip Technology Inc.
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