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  • Author Author: COMPACT
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Project "code name" PostScript 010

COMPACT

July 15th

Some Odd Quirks

I've been busy performing System Integration Testing and Unit Testing and have encountered a few hurdles on the way.

 

1. CCSv5/MSP430 C Compiler and handling of long variables.

I've always used long variables with the premise that they have a minimum size of 32 bits.

After encountering odd behaviour and through debugging I have found that with CCSv5 and MSP430FR5739 the compiler wants to use a 16 bit register thus truncating its value.

A work around is available. I forced the compiler to use RAM with the volatile keyword.

After using it I got the expected behaviour.

 

Note: The MSP430 Optimizing C/C++ Compiler v 4.1 manual says that longs are 32 bit values.

The E2E Community forum confirms my finding.

 

I also noticed that the stepping function through some long arithmentic was not consistent. some lines were skipped but at the end of the calculations the value of the long variable was correct.

 

 

2. Basic WiFi Demo Buffer size strikes again.

From odd behaviour from my project I had to perform some debugging to find that there appears to be a 256 byte limit for the receive buffer size.

The work around is to limit the receive buffer size to 256.

  • Getting buffer size correct is a common problem I have observed in most distributed architectures.

    It usually takes a while to assess the message traffic to see if your are sending too much data or too rapidly updating the status readouts.

    Most projects I reviewed end up adjusting buffer size and message timing to work around the undocumented limitations of some of the components.

     

    Overall, you have done a good job keeping the readers updated on your progress and issues.  I think we all learned a lot about the MSP430 line during the road test.

     

    Good job,

    DAB