Trace function too slow? (Keil)

[antoine]

Posted on August 02, 2016 at 14:43

I use two ADCs, working together on two different signals.

These two signals have the same frequency and amplitude. They are shifted, Signal 2 has a phase of 90°.The DMA put the converted values in an array. This array is printed circularly in the Debug Viewer.I have one column of values for each signal.The ADCs seem to work correctly, however I have a doubt: is it possible that the Trace is too slow?Typically, I have this kind of result: </colgroup>

1986 5

1924 3

1865 3

1803 4

1742 5

1683 11

1623 18

1564 27

1503 34

1439 50

1376 54

1314 68

1260 88

1202 108

1145 131

1091 155

1035 179

979 208

929 239

884 280

834 314

784 347

733 385

687 423

641 463

593 501

554 546

510 589

470 635

423 681

392 3603

2556 3578

2611 3553

2667 3524

So you can see here that there is a gap, several values are likely skipped during the printing process.Here is the graphic output of the values from both ADCs.As you can see, this happens several times, but this left aside, the two signals are correctly treated.During the execution in debug mode, I have the message ''Trace: data overflow''.So I think it is just about the display of the values, but I wanted to be sure.Should I be concerned about this, or should I just assume that the values exist in the memory and the Trace just fails to show them properly?

[AvaTar]

Posted on August 02, 2016 at 15:21

> The ADCs seem to work correctly, however I have a doubt: is it possible that the Trace is too slow?

If your trace runs concurrently with debugging over SWD, sure. Debug and trace are sharing bandwidth in this case. Professional debug pods with real-time trace (ETM) will cost you about 1k bucks (€ or $). Consider tracing (in your case) just useful for verification. Once the code-under-test is proven to work, turn tracing off.

[antoine]

Posted on August 02, 2016 at 15:23

Good to know, thank you 🙂