MS5803-30BA
Miniature 30 bar Module
SENSOR SOLUTIONS ///MS5803-30BA
FUNCTIONAL DESCRIPTION
Figure 1: Block diagram of MS5803-30BA
GENERAL
The MS5803-30BA consists of a piezo-resistive sensor and a sensor interface IC. The main function of the MS5803-
30BA is to convert the uncompensated analogue output voltage from the piezo-resistive pressure sensor to a 24-
bit digital value, as well as providing a 24-bit digital value for the temperature of the sensor.
FACTORY CALIBRATION
Every module is individually factory calibrated at two temperatures and two pressures. As a result, 6 coefficients
necessary to compensate for process variations and temperature variations are calculated and stored in the 128-
bit PROM of each module. These bits (partitioned into 6 coefficients W1 to W6) must be read by the microcontroller
software and used in the program converting D1 and D2 into compensated pressure and temperature values.
The 2 coefficients W0 and W7 are for factory configuration and CRC.
SERIAL INTERFACE
The MS5803-30BA has built in two types of serial interfaces: SPI and I
2
C. Pulling the Protocol Select pin PS to low
selects the SPI protocol, pulling PS to high activates the I
2
C bus protocol.
SPI MODE
The external microcontroller clocks in the data through the input SCLK (Serial CLocK) and SDI (Serial Data In). In
the SPI mode module can accept both mode 0 and mode 3 for the clock polarity and phase. The sensor responds
on the output SDO (Serial Data Out). The pin CSB (Chip Select) is used to enable/disable the interface, so that
other devices can talk on the same SPI bus. The CSB pin can be pulled high after the command is sent or after the
end of the command execution (for example end of conversion). The best noise performance from the module is
obtained when the SPI bus is quiet and without communication to other devices during the ADC conversion in
progress.
