lm95172qa2 National Semiconductor Corporation, lm95172qa2 Datasheet - Page 13

• Manufacturer Part Number: lm95172qa2
• Description: 13-bit To 16-bit Digital Temperature Sensor With 3-wire Interface
• Manufacturer: National Semiconductor Corporation

1.4 COMMUNICATING WITH THE LM95172QA2 MDA
The serial interface consists of three lines: CS (Chip Select),
SC (Serial Clock), and the bi-directional SI/O (Serial I/O) data
line. See (Note 7)for CS voltage restriction. A high-to-low
transition of the CS line initiates the communication. The
master (processor) always drives the chip select and the
clock. The first 16 clocks shift the temperature data out of the
LM95172QA2 MDA on the SI/O line (a temperature read).
Raising the CS at anytime during the communication will ter-
minate this read operation. Following this temperature read,
the SI/O line becomes an input and a command byte can be
FIGURE 13. Reading the Temperature Register followed by a read or write from another register (Control/Status, T
FIGURE 14. Reading the Temperature Register followed by repeated commands and Data Register accesses (Control/
FIGURE 12. Reading the Temperature Register
Status, T
T
LOW
HIGH
, or Identification register)
, T
LOW
, or Identification register)
13
written to the LM95172QA2 MDA. This command byte con-
tains a R/W bit and the address of the register to be commu-
nicated with next (see Section 1.7 Internal Register Struc-
ture). When writing, the data is latched in after every 8 bits.
The processor must write at least 8 bits in order to latch the
data. If CS is raised before the falling edge of the 8th com-
mand bit, no data will be latched into the command byte. If
CS is raised after the 8th bit, but before the 16th bit, of a write
to a 16-bit data register, only the most significant byte of the
data will be latched. This command-data-command-data se-
quence may be performed as many times as desired.
30035714
30035716
www.national.com
30035715
HIGH
,