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CCS/TMS320F28035: How frequently "Graph" can update its data?

Hisao Uchikoshi
Genius 15170 points
Part Number: TMS320F28035
Other Parts Discussed in Thread: C2000WARE

Tool/software: Code Composer Studio

Hi,

I would like to monitor a specific RAM data defined as global variable by graph function on CCS. I tested below.

CCS 8.2

Windows 10

F28035 Control card

Sample code : C:\ti\c2000\C2000Ware_1_00_05_00\device_support\f2803x\examples\c28\adc_soc

Modified the code to remove an increment to watch a single buffer as below.

Below is the graph property for Voltage1[0].

Now the signal generator inputs 1Hz analog sin wave to AIN4 pin of F28035. The graph shows as below.

Then, inputting 0.1Hz signal which is slower than 1/10 and the graph now looks like good.

It looks that the most fastest frequency is less than 1Hz. I would like to monitor the data more frequently more than 1000Hz or 1KHz. What is the realistic maximum "sampling Rate Hz" for F28035?

Does TI have any solution for our inquiry?

Regards,

Uchikoshi

  • 0
    TI__Guru**** 171309 points
    Uchikoshi,

    Do you know where are you setting the breakpoint to update the graph? This operation takes quite some time to complete (when compared to the speed of the ADC) due to the lag introduced by the JTAG communications.

    That is the main reason to use a buffer, given that a bulk data transfer of several variables is faster than several transfers of a single value. This allows time for the data transfer to happen and increases the chances the data will be graphed without gaps.

    In this case, you can uncomment line 250 and set a breakpoint that updates the graph. Then you can set the Acquisition Buffer to 10, which will cause the graph tool to read ten 16-bit signed integers starting from the address of Voltage1.

    Also, given that arrays are pointers in nature, you can simply pass "Voltage1" as the "Start Address " parameter.

    Realistically the graphs can be updated at about 1/2 second and, under very special circumstances, get down to 1/10 second.

    Hope this helps,
    Rafael