CRCMB - Revision history

Admin: Created page with "= Action = Returns the Modbus CRC value of a variable or array.
2017-01-17T20:27:34Z

Created page with "= <span class="f_Header">Action</span> = Returns the Modbus CRC value of a variable or array. <span style="font-family: Arial;"> </span> <span style="font-family: Aria..."

New page
= <span class="f_Header">Action</span> =

Returns the Modbus CRC value of a variable or array.

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= <span class="f_Header">Syntax</span> =

Var = <span class="f_Syntax">CRCMB</span>( source , L)

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= <span class="f_Header">Remarks</span> =
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Var

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The variable that is assigned with the modbus checksum of variable source. This should be a word variable.

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Source

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The source variable or first element of the array to get the checksum of.

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L

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The number of bytes to check.

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CRC8 is used in communication protocols to check if there are no transmission errors.

The Modbus checksum uses a different polynome.

 

<span style="font-family: Arial;">Modbus.lbx or modbus.lib need to be included in your project using the $LIB directive</span>

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= <span class="f_Header">See also</span> =

[[CHECKSUM]] , [[CRC16]], [[CRC16UNI]] , [[CRC32]] , [[TCPCHECKSUM]] , [[CRC8]]

 

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= <span class="f_Header">Example</span> =

<source lang="bascomavr">
$regfile = "m48def.dat" ' specify the used micro
$crystal = 8000000 ' used crystal frequency
$baud = 19200 ' use baud rate
$hwstack = 32 ' default use 32 for the hardware stack
$swstack = 10 ' default use 10 for the SW stack
$framesize = 40 ' default use 40 for the frame space

Config Com1 = Dummy , Synchrone = 0 , Parity = None , Stopbits = 1 , Databits = 8 , Clockpol = 0

Dim Ar(10) As Byte
Dim W As Word

Ar(1) = 1
Ar(2) = 2
Ar(3) = 3

W = CrcMB(ar(1) , 3) 'calculate value

Print W

End
</source>

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[[Category:BASCOM Language Reference]]