MCP9808
the maximum and minimum temperature boundary or
temperature window that can be used to monitor
ambient temperature. If this feature is enabled
(Section 5.1.1 “Sensor Configuration Register
(CONFIG)”) and the ambient temperature exceeds the
specified boundary or window, the MCP9808 asserts an
Alert output. (Refer to Section 5.2.3 “Alert Output
Configuration”).
5.1.2
UPPER/LOWER/CRITICAL
TEMPERATURE LIMIT REGISTERS
(TUPPER/TLOWER/TCRIT
)
The MCP9808 has a 16-bit read/write Alert Output
Temperature Upper Boundary register (TUPPER), a 16-bit
Lower Boundary register (TLOWER) and a 16-bit Critical
Boundary register (TCRIT) that contain 11-bit data in
two’s complement format (0.25°C). This data represents
REGISTER 5-3:
TUPPER/TLOWER/TCRIT UPPER/LOWER/CRITICAL TEMPERATURE LIMIT REGISTER
(→ ADDRESS ‘0000 0010’b/‘0000 0011’b/‘0000 0100’b)(1)
U-0
—
U-0
—
U-0
—
R/W-0
Sign
R/W-0
27°C
R/W-0
26°C
R/W-0
25°C
R/W-0
24°C
bit 15
bit 8
R/W-0
23°C
R/W-0
22°C
R/W-0
21°C
R/W-0
20°C
R/W-0
2-1°C
R/W-0
2-2°C
U-0
—
U-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
bit 15-13
bit 12
Unimplemented: Read as ‘0’
Sign: Sign bit
0= TA ≥ 0°C
1= TA < 0°C
bit 11-2
bit 1-0
TUPPER/TLOWER/TCRIT: Temperature Boundary bits
Temperature boundary trip data in two’s complement format.
Unimplemented: Read as ‘0’
Note 1: This table shows two 16-bit registers for TUPPER, TLOWER and TCRIT, located at ‘0000 0010b’,
‘0000 0011b’ and ‘0000 0100b’, respectively.
DS25095A-page 22
© 2011 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
