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MDP200 Datasheet_V1.3

April 2018

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Equation (2)

Temperature = 0.2926 × Tcount - 124.7073

For example, while Tcount_Hi = 0x01, Tcount_Lo = 0xFF, Temperature ≈ 24.8ºC

Note:

‘0x’ mean the number is hexadecimal.

5.7

Reset Command

MDP200’s circuit can be reset to initial status by writing reset command 0xFE into

device.

Note:

The device will not work normally until 2 seconds after writing reset command. Do not write any

data into device within 2 seconds after writing reset command or there will be unpredictable error.

5.8

CRC-8 Redundant Data Transmission

MDP200 use cyclic redundancy checking (CRC) technique for error detection in

I2C transmission. The master appends an 8-bit checksum to the actual data

sequence. The checksum holds redundant information about the data sequence

and allows the receiver to detect transmission errors. The computed checksum

can be regarded as the remainder of a polynomial division, where the dividend is

the binary polynomial defined by the data sequence and the divisor is a “generator

polynomial”. The MDP200 implements the CRC-8 standard based on the

generator polynomial x8 + x5 + x4 +1.

The master’s program must use the 2 bytes differential pressure reading from

MDP200’s register 0 and polynomial x8 + x5 + x4 +1 to calculate out the one byte

result data. Then compare the result data calculated by master and the CRC code

from MDP200. If they are not equal, it indicates that there is error in I2C

communication. The master must discard the measurement data and trigger

measurement again, then read from MDP200’s register 0 until the result data and

the CRC code are equal. Appendix at the end of this document is C code for

reference.

Note:

CRC is only used for data transmitted from slave to master. For the details of the cyclic redundancy

check, please refer to the relevant literature.