Inherited a legacy PSoC 4 project and am trying to get up to speed on the family and PSoC Creator. After building the project, under the "Debug" menu, the options for Debug, Debug without Programming, etc. are greyed out. If I try to "Select Debug Target", the box is empty. I compared this with a sample project from the PSoC 4 Pioneer kit (which debugs fine), and can't seem to figure out if there's a setting or something I'm missing. 

Anyone have any suggestions?  

Hello,

I am using PSoC 4500 S to estimate the execution time of algorithms. For this purpose, I started to measure different arithmetic operations with the Systick-Timer (microbenchmarks).

However, especially floating point operations show a non-linear progression of execution time depending on the input data. For example cosf varies between 79000 us and 1051020 us (each for 1000 iterations). This missing determinsim makes it difficult to extract a tight bound from the microbecnhmarks for execution time estimation.

I attached a little overview of the min and max measurements as an excel sheet. It is also noticeable that floating point division highly depends on the  input data and the order of the operations (denominator and numerator). For validation I measured the times with code optimization (O3) and without code optimization (Debug). Furthermore, I analyzed the assembler code to gain further information - without success. 

Here a code snippet how I measure the cosf function. The entire measurement routine is validated and can be excluded as a source of error:

////////////////////////////////////////////////////////////////////////////////////////////

int num_points;
float sortedArray[2000];

for(i = 0; i < 2000; i++)
{
 sortedArray[i] = i*3.1415;
}

for (num_points = 0; num_points <= 2000; num_points++)

{
START_TIME = SysTick->VAL // Start timer

// Microbenchmark: cos

for( i = 0; i < 1000; i++)
{
result1 = cosf(sortedArray[num_points]);
}

STOP_TIME = SysTick->VAL; // Stop timer

}

////////////////////////////////////////////////////////////////////////////////////////////

On the second sheet of the excel file you find the measurements for the first 100 number of points (num_points) for cosf-microbenchmark . Here is mean the metric of interest.

How is this non-determinsim in arithmetic operations explainable?

I expected approximately equal execution times for each class of arithmetic operations (fDiv, fMul, fcos,...).

Best Regards

Jannik 

hi friends

  i have a trouble when i am using  SPI to communicate with a fram .I would like to know why using spi communication must use a delay function after sending a byte and before reading it, if no delay function is used, there will be a shift.(0x01,0x02,0x03 will become 0x00 0x01 0x02).And the delay time is different, the shift is different