MS4515DO Datasheet, PDF (16/19 Pages) List of Unclassifed Manufacturers – PCB Mounted Digital Output Transducer

MS4515DO
2. SPI Interface Specification
The SPI interface of sensor can be programmed for falling-edge MISO change.
2.2 SPI Read_DF (Data Fetch)
For simplifying explanations and illustrations, only falling edge SPI polarity will be discussed in the following
sections. The SPI interface will have data change after the falling edge of SCLK. The master should sample
MISO on the rise of SCLK. The entire output packet is 4 bytes (32 bits). The high bridge data byte comes first,
followed by the low bridge data byte. Then 11 bits of corrected temperature (T[10:0]) are sent: first the
T[10:3]byte and then the {T[2:0],xxxxx} byte. The last 5 bits of the final byte are undetermined and should be
masked off in the application. If the user only requires the corrected bridge value, the read can be terminated
after the 2nd byte. If the corrected temperature is also required but only at an 8-bit resolution, the read can be
terminated after the 3rd byte is read.
SCLK
MISO HiZ
S1 S0 B13 B12
B7 B6
B0 T10 T9
T1 T0 HiZ
SS
Packet = [ {S(1:0),B(13:8)},{B(7:0)},{T(10:3)},{T(2:0),xxxxx}] Where
S(1:0) = Status bits of packet (normal, command, busy, diagnostic)
B(13:8) = Upper 6 bits of 14-bit bridge data.
B(7:0) = Lower 8 bits of 14-bit bridge data.
T(10:3) = Corrected temperature data (if application does not require corrected temperature, terminate read early)
T(2:0),xxxxx =. Remaining bits of corrected temperature data for full 11-bit resolution
HiZ = High impedance
Figure 2.2 – SPI Output Packet with Falling Edge SPI_Polarity
MS4515DO
www.meas-spec.com
16/19
April 2012