Modbus RTU for RM46

Safiullah Hussaini

Other Parts Discussed in Thread: RM46L852

Hi,

I am trying to implement a Modbus RTU library for the RM46L852 chip. Is there an existing library that I can use as a starting point?

What would be the correct way to use the DMA, CRC and SCI peripherals? Should I even use the DMA and the CRC units at all?

over 9 years ago

0 KARTHIKEYAN RAJAMANICKAM over 9 years ago

TI__Genius 11645 points

Safiullah,

We might not have a Modbus library that is readily available with Hercules.

Following is the closest thread that I was able to search through
e2e.ti.com/.../1193910

DMA aids faster data transfers and SCI for communication.

But CRC module inside hercules devices are intended to verify the integrity of the memory sub system by calculating signature for a set of data and compare the signature to make sure data is consistent.

0 Safiullah Hussaini over 9 years ago in reply to KARTHIKEYAN RAJAMANICKAM

Intellectual 885 points

So I cant really perform a CRC-16 check on the data packet residing in memory?

0 KARTHIKEYAN RAJAMANICKAM over 9 years ago in reply to Safiullah Hussaini

TI__Genius 11645 points

Saifullah,

our CRC is based on a 64-bit PSA derived from a primitive polynomial as per the following equation

f(x) = x64+ x4+ x3+ x + 1.

During a non-doubleword write access to PSA, all unwritten byte lanes are padded with zero’s before compression, and the compressed value is always expressed in 64 bit.

If you are looking for using a different polynomial then it doesn't help.

0 Safiullah Hussaini over 9 years ago in reply to KARTHIKEYAN RAJAMANICKAM

Intellectual 885 points

Thanks, thats exactly what I wanted to know.

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Modbus RTU for RM46