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Port pins too slow

Erwin Meyer

Hi..

I have a problem with the xc167ci. Its I/O-Pins toggle too slowly. If I have e.g. pin 4^0 toggeling, it only works with 2,85 MHz instead of 40 MHz (system clock).
I use the following sourcecode:

while(1)
{
P9_0 = 0;
P9_0 = 1;
}
In EBC-Mode the pins are pretty fast, they work on a 25 ns basis. Why does that not work on normal I/O-Pin operations?

Thanks,
Erwin

Parents
  • 0

    Just a guess: maybe your program execution is generally slow, say, because it is being executed from external memory with slow access times. Besides, I got the impression that Keil's startup code for XC16x does not enable CPU speedups, such as Branch Prediction, Zero Cycle Jump, Instruction FIFO etc. I'm not very familiar with XC16x, so please look that up in the manuals.

    - mike

Reply
  • 0

    Just a guess: maybe your program execution is generally slow, say, because it is being executed from external memory with slow access times. Besides, I got the impression that Keil's startup code for XC16x does not enable CPU speedups, such as Branch Prediction, Zero Cycle Jump, Instruction FIFO etc. I'm not very familiar with XC16x, so please look that up in the manuals.

    - mike

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