Datasheet
MCP9843/98243
DS22153C-page 24 © 2009 Microchip Technology Inc.
5.1.3 UPPER/LOWER/CRITICAL
TEMPERATURE LIMIT REGISTERS
(T
UPPER
/T
LOWER
/T
CRIT
)
The MCP9843/98243 device has a 16-bit read/write
Event output Temperature Upper-Boundary Trip
register (T
UPPER
), a 16-bit Lower-Boundary Trip
register (T
LOWER
) and a 16-bit Critical Boundary Trip
register (T
CRIT
) that contains 11-bit data in two’s
complement format (0.25°C). This data represents the
maximum and minimum temperature boundary or
temperature window that can be used to monitor
ambient temperature. If this feature is enabled
(Section 5.1.2 “Sensor Configuration Register
(CONFIG)”) and the ambient temperature exceeds the
specified boundary or window, the MCP9843/98243
asserts an Event output. (Refer to Section 5.2.3
“Event Output Configuration”).
REGISTER 5-4: UPPER/LOWER/CRITICAL TEMPERATURE LIMIT REGISTER (T
UPPER
/T
LOWER
/
T
CRIT
) → ADDRESS ‘0000 0010’b/‘0000 0011’b/‘0000 0100’b (NOTE 1)
U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
———Sign2
7
°C 2
6
°C 2
5
°C 2
4
°C
bit 15 bit 8
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 U-0 U-0
2
3
°C 2
2
°C 2
1
°C 2
0
°C 2
-1
°C 2
-2
°C — —
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 15-13 Unimplemented: Read as ‘0’
bit 12 Sign:
0 =T
A
≥ 0°C
1 =T
A
< 0°C
bit 11-2 T
UPPER
/T
LOWER
/T
CRIT
:
Temperature boundary trip data in two’s complement format.
bit 1-0 Unimplemented: Read as ‘0’
Note 1: This table shows two 16-bit registers for T
UPPER
, T
LOWER
and T
CRIT
located at ‘0000 0010b’,
‘0000 0011b’ and ‘0000 0100b’, respectively.