MSP430FR5739 CRC C code example

Andres Mora

Other Parts Discussed in Thread: MSP430FR5739, MSP430WARE, MSP430F6638

Hello forum,

I have a 9600 8N1 communication going on between two MSP430FR5739s and would like to integrate a check for corrupted messages using the CRC module. Does anyone have some C code around or can point me to an example that implements it?

Thanks in advance!

over 13 years ago

0 kazola over 13 years ago

Guru 18605 points

Hi!

Some time ago I used something similar to the page 32 in this link:

http://www.metratec.com/fileadmin/docs/en/documentation/metraTec_MiFare_Protocol-Guide.pdf

In this link you have also something which the authors claim to be tested with Code Composer Studio :)

http://www.ccsinfo.com/forum/viewtopic.php?t=24977

Good luck!

0 Andres Mora over 13 years ago in reply to kazola

Prodigy 205 points

Thanks Kazola!

Those are helpful linkns, however, I am not looking into writing the CRC check routine but in learning how to use the already present CRC module/registers of the MSP430FR5739. I think implementing the CRC code would be doing the same job twice.

Thanks again for you help though!

Andres

0 Chester Gillon over 13 years ago in reply to Andres Mora

Guru 92251 points

Have you seen the examples\devices\5xx_6xx\MSP430F563x, MSP430F663x Code Examples\C\msp430f66xx_crc16_01.c example in MSP430ware_1_20_01_08?

It compares the results of a software CRC against the CRC hardware module.

(While this example was written for a different device, it also works on a MSP430FR5739 - you just have to change the #include<msp430f6638.h> to #include <msp430.h>)

0 Andres Mora over 13 years ago in reply to Chester Gillon

Prodigy 205 points

Hi Chester,

Thanks for the information! Do you have the actual link to those files?

Cheers!

0 TonyKao over 13 years ago in reply to Andres Mora

Genius 3770 points

If you look at the device family user guide http://www.ti.com/lit/ug/slau272a/slau272a.pdf it appears the CRC unit is just a collection of registers to read and write data.

// initializes CRC with seed, depends on CRC version
  CRCINIRES = seed;
  // write each word to input register
  for(i = 0; i < len; ++i)
    CRCDI = data[i];
  // reads CRC result
  int crcResult = CRCINIRES;

I don't have the particular device so couldn't test it, but that should give you an idea for how to use the CRC unit.

Tony

0 Chester Gillon over 13 years ago in reply to Andres Mora

Guru 92251 points

Andres Mora said:
Do you have the actual link to those files?

They are part of MSP430Ware.

If you have Code Composer Studio 5 installed, the examples will under a directory such as C:\ti\ccsv5\ccs_base\msp430\msp430ware_1_20_00_16

Failing that, http://www.ti.com/tool/msp430ware contains a download link.

0 Andres Mora over 13 years ago in reply to Chester Gillon

Prodigy 205 points

Thanks a lot TonyKao and Chester!

TonyKao that was what I was looking for and Chester, sorry I didn't understand before what you meant but yes, after looking at CSS I found the examples you mentioned.

Once again thanks a lot to the both of you!

0 Andy Aoe over 11 years ago in reply to Andres Mora

Prodigy 160 points

I'm glad I found this page.

I've copied the CCITT_Update algorithm into my code and have verified that it matches the results of the CRC hardware.

I'm using the CCITT_Update function to calculate the CRC for BSL packets to the MSP430FR5739. The BSL User Guide (SLAU319H) tells me to calculate the CRC using the payload. So in the example:

Host: 80 02 00 52 02 90 55

The payload is 52 and 02 so when I calculate the CRC, I have to treat the second number as the MSB and calculate the CRC using 0x0252 and I indeed get 0x5590 which matches with this example. Hurray!

In the next example:

Host: 80 01 00 1A 8B 52

There is only 1 byte payload, 0x1A, so I calculate the checksum with 0x001A but it does not produce 0x528B.

Does anybody know how to calculate the CRC with single or odd sized payloads?

0 Chester Gillon over 11 years ago in reply to Andy Aoe

Guru 92251 points

Andy Aoe said:
In the next example:
Host: 80 01 00 1A 8B 52

There is only 1 byte payload, 0x1A, so I calculate the checksum with 0x001A but it does not produce 0x528B.

I looked at the source files in the BSL scripter slau319h.zip

Looking at the CRC calls made by the UART_5xx_TXPacket() function in BSL_Files/BSL Scripter/source/BSL_UART_Protocol_5xx.c, by manually calculating the CRC for a one byte payload of 0x1A as that example code does, the CRC was 0x528B.

0 Andy Aoe over 11 years ago in reply to Chester Gillon

Prodigy 160 points

Hi Chester, how do I get my hands on slau319h.zip?

0 Chester Gillon over 11 years ago in reply to Andy Aoe

Guru 92251 points

Andy Aoe said:
Hi Chester, how do I get my hands on slau319h.zip?

The download link for the software is http://www.ti.com/lit/zip/slau319

And for the documentation http://www.ti.com/lit/pdf/slau319

0 Andy Aoe over 11 years ago in reply to Chester Gillon

Prodigy 160 points

Awesome Thanks!

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MSP430FR5739 CRC C code example