Datasheet

POINTER REGISTER TEMPERATURE REGISTER
I/O
Control
Interface
SCL
SDA
Temperature
Register
Configuration
Register
T
LOW
Register
T
HIGH
Register
Pointer
Register
TMP112
www.ti.com ......................................................................................................................................................... SBOS473B – MARCH 2009 – REVISED JUNE 2009
Figure 11 shows the internal register structure of the The Temperature Register of the TMP112 is
TMP112. The 8-bit Pointer Register of the device is configured as a 12-bit, read-only register
used to address a given data register. The Pointer (Configuration Register EM bit = '0'; see the Extended
Register uses the two LSBs (see Table 11 ) to identify Mode section), or as a 13-bit, read-only register
which of the data registers should respond to a read (Configuration Register EM bit = '1') that stores the
or write command. Table 1 identifies the bits of the output of the most recent conversion. Two bytes must
Pointer Register byte. During a write command, P2 be read to obtain data, and are described in Table 3
through P7 must always be '0'. Table 2 describes the and Table 4 . Note that byte 1 is the most significant
pointer address of the registers available in the byte (MSB), followed by byte 2, the least significant
TMP112. The power-up reset value of P1/P0 is '00'. byte (LSB). The first 12 bits (13 bits in Extended
By default, the TMP112 reads the temperature on mode) are used to indicate temperature. The least
power-up. significant byte does not have to be read if that
information is not needed. The data format for
temperature is summarized in Table 5 and Table 6 .
One LSB equals 0.0625 ° C. Negative numbers are
represented in binary twos complement format.
Following power-up or reset, the Temperature
Register reads 0 ° C until the first conversion is
complete. Bit D0 of byte 2 indicates Normal mode
(EM bit = '0') or Extended mode (EM bit = '1'), and
can be used to distinguish between the two
temperature register data formats. The unused bits in
the Temperature Register always read '0'.
Table 3. Byte 1 of Temperature Register
(1)
D7 D6 D5 D4 D3 D2 D1 D0
T11 T10 T9 T8 T7 T6 T5 T4
(T12) (T11) (T10) (T9) (T8) (T7) (T6) (T5)
(1) Extended mode 13-bit configuration shown in parentheses.
Table 4. Byte 2 of Temperature Register
(1)
Figure 11. Internal Register Structure
D7 D6 D5 D4 D3 D2 D1 D0
T3 T2 T1 T0 0 0 0 0
Table 1. Pointer Register Byte
(T4) (T3) (T2) (T1) (T0) (0) (0) (1)
P7 P6 P5 P4 P3 P2 P1 P0
(1) Extended mode 13-bit configuration shown in parentheses.
0 0 0 0 0 0 Register Bits
Table 2. Pointer Addresses
P1 P0 REGISTER
0 0 Temperature Register (Read Only)
0 1 Configuration Register (Read/Write)
1 0 T
LOW
Register (Read/Write)
1 1 T
HIGH
Register (Read/Write)
Copyright © 2009, Texas Instruments Incorporated Submit Documentation Feedback 7
Product Folder Link(s): TMP112