Copying variables

RE: Copying variables

Kenneth — Mon, 03 Dec 2018 13:12:00 GMT

It's the first I have seen of this. Can you modify one of the \nRF5_SDK_15.2.0_9412b96\examples such that I can recreate it here?

RE: Copying variables

iQd — Sat, 01 Dec 2018 15:54:55 GMT

I am having a strange behaviour also elsewhere.

I make an if conditional:

if (var1 != buffer[1] || var2 != buffer[2] || var3 != buffer[3] || var4 != buffer[4] || var5 != buffer[5] || var6 != buffer[6])
    {
        // do something.
    }

var1...var6 are uint8, buffer[x] array is uint8 as well.
Even though the var1...6 variables have the SAME values as the comparison buffer indexes, the code in the if conditional will be run.

I have tested the above problem and this on three different machines, they work the same way.

Only if I break this conditional statement into six separate blocks where I compare only one variable to one array index, AND add a 50us delay before that - the code actually works.

I have entered the Twilight Zone somehow, I cannot even trust a processor run it's code without random issues.
I tried this also on another Nordic 52832 DK board - same effect.

What could I have so much wrong that code starts behaving like this?
I get no errors, code compiles normally and runs otherwise ok.

RE: Copying variables

iQd — Fri, 30 Nov 2018 17:27:33 GMT

I tested how low I can go with the delays and still get values copied ok.

It seems that 5 us is the limit between working code and non-working code.

If I set the delay to 2 us, only one or two variable values are copied.
Delay of 3 us will make all but the first two variables copied ok.
Delay of 4 us will make only the two last array indexes copied ok.

When the delay is 5 us, all values are copied ok and the code actually works.

I have never seen an issue like this, I lose valuable time with this kind of problems that should not even exist.
This is not even the first time this happens with the 52832, I am starting to lose trust in the 52832.

I had earlier a similar issue where, at startup I set a variable to a certain value, nothing else touches this variable until the main loop.
Then, at the main loop when I check the value, the variable is somehow changed to a different value.
I was able to go around this only by setting the variable to the value I want, two times right before the main loop.

I am using the Nordic DK board, Segger v3.40 in Windows 7 x64, GNU ARM Embedded Toolchain version 7-2017-q4-major.