MCP9808 MICROCHIP [Microchip Technology], MCP9808 Datasheet - Page 16

• Manufacturer Part Number: MCP9808
• Manufacturer: MICROCHIP [Microchip Technology]

MCP9808
5.1
The MCP9808 has several registers that are
user-accessible. These registers include the Tempera-
ture register, Configuration register, Temperature Alert
Upper Boundary and Lower Boundary Limit registers,
Critical Temperature Limit register, Manufacturer
Identification register and Device Identification register.
The Temperature register is read-only, used to access
the ambient temperature data. This register is double-
buffered and it is updated every t
Alert Upper Boundary and Lower Boundary Limit
registers are read/write registers. If the ambient
temperature drifts beyond the user-specified limits, the
MCP9808 outputs a signal using the Alert pin (refer to
REGISTER 5-1:
DS25095A-page 16
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7-4
bit 3-0
Note 1:
W-0
—
Registers
Some registers contain calibration codes and should not be accessed.
W: Writable bits
Write ‘0’.
Bits 7-4 must always be cleared or written to ‘0’. This device has additional registers that are reserved
for test and calibration. If these registers are accessed, the device may not perform according to the
specification.
Pointer bits
0000 = RFU, Reserved for Future Use (Read-Only register)
0001 = Configuration register (CONFIG)
0010 = Alert Temperature Upper Boundary Trip register (T
0011 = Alert Temperature Lower Boundary Trip register (T
0100 = Critical Temperature Trip register (T
0101 = Temperature register (T
0110 = Manufacturer ID register
0111 = Device ID/Revision register
1000 = Resolution register
1xxx = Reserved
W-0
—
REGISTER POINTER (WRITE-ONLY)
W = Writable bit
‘1’ = Bit is set
CONV
(1)
W-0
. The Temperature
—
A
W-0
)
—
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
CRIT
Section 5.2.3 “Alert Output
addition, the Critical Temperature Limit register is used
to provide an additional critical temperature limit.
The
configure the MCP9808 device’s various features.
These registers are described in further detail in the
following sections.
The registers are accessed by sending a Register
Pointer to the MCP9808, using the serial interface. This
is an 8-bit write-only pointer. However, the four Least
Significant bits are used as pointers and all unused bits
(Register Pointer<7:4>) need to be cleared or set to ‘0’.
Register 5-1
each register.
W-0
)
Configuration
UPPER
LOWER
describes the pointer or the address of
W-0
)
)
Pointer bits
register
© 2011 Microchip Technology Inc.
x = Bit is unknown
W-0
provides
Configuration”). In
access to
W-0
bit 0