sampling rate versus continuous refresh interval

Thomas,

The Sampling rate HZ property in the CCS graph is used in conjunction with the Time Display Unit property. These two parameters set arbitrary values that simply format the X axis to display data, therefore have no correlation with the refresh rate the emulator is capable of.

Therefore if the sampling rate is too high and Acquisition Buffer Size is set to 1 (meaning reading a single sample at a time), chances are the graph will skip sampled values and will not look right. In other words, by the time the graph thinks it is displaying the "n+1" sample, the high rate in hardware will actually have its value updated to, say "n+5" sample.

To workaround this you can create a buffer of "n" values in the target code and update the Acquisition Buffer Size to the value "n". This way the graph update rate will be reduced - keep in mind that the emulator has a limit to its data throughput, therefore it is a process of trial and error to find a good buffer size that allows displaying the data. Also, the continuous graph updates stop the execution on the target (a breakpoint), therefore be aware of any potential effects this will cause to the real-time execution.

The pages below can help you with some of the configuration details:

http://processors.wiki.ti.com/index.php/Graph_Visualization_for_MSP430

http://processors.wiki.ti.com/index.php/GSG:Debugging_projects

Hope this helps,

Rafael