MPS-301A World Products, Inc., MPS-301A Datasheet - Page 7

• Manufacturer Part Number: MPS-301A
• Description: Integrated, Absolute Pressure Sensor
• Manufacturer: World Products, Inc.

SPI INTERFACE DESCRIPTION – OPTION’ S
SPI PIN SIGNALS
There are four I/O signals associated with SPI transfers: SCK (pin 4), MISO (pin 2), MOSI (used by the
manufacturer for calibration purposes only) and SS (pin 3). SCK is an input pin for the clock signal from the master
which synchronizes the data transfer between the master and slave devices. Slave devices ignore the SCK signal
unless the SS pin is active low. Data is shifted on the rising edge of the SCK signal and is sampled on the opposite
edge where the data is stable.
The MISO and MOSI data pins are used for transmitting and receiving serial data. For the slave the MOSI is the
data input line and the MOSI is the data output line. Once selected by the master the slave optionally drives data
out its MOSI pin to the MISO of the master. The MOSI pin of the MTCM is solely for manufacturer’ s use and the
customer is advised to disconnect this in their application.
The SS pin is used by the master to enable the SPI slave for a transfer. If the SS pin of a slave is inactive (High),
the device ignores SCK clocks and keeps the MISO output pin in a high impedance state. The MBAP is always the
slave and it is assumed in most cases the master is a microcontroller (MCU).
READING THE PRESSURE AND TEMPERATURE (OPTION ST)
To read the pressure/temperature value, power up the device and wait for > 25ms. After that read the data from the
MISO pin. Five bytes have to be read out. MSB is transmitted first. The first byte is a dummy byte always set to
0xFF. For the second and fourth byte only the last seven bits should be considered with the eighth bit (the MSB)
always set to binary 0. The third and fifth byte should be read as normal, MSB first. The pressure and temperature
SCK
SS
MISO
Integrated, Absolute Pressure Sensor
T1 T2
T3
First Byte (dummy)
Always 0xFF
MPS-301A
1907 Westlands Centre, 20 Westlands Road, Quarry Bay, Hong Kong
Tel : [phone]
Email : [e-mail]
Website : www.jlworld.com
Second Byte (only last
7 bits considered) 0x10
Note 1
Fax : [phone]
Note 2
Third Byte 0x00
Document #E:DS-SHPS-MPS301A Rev A
Note 3
060347-A2
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