Chain tool speed

[roscop13]

Hello I'v just ordered a NRF51-DK kit.

I'm looking at the different tool chain. In my application speed is critical 16Mhz is actually bearly enough, so my question is:

-Is there a difference in the execution speed of the same code written : Keil , eclipse GCC, or Mbed?

-I see that the NRF51-DK is actually running at 32Mhz, is this ok to put a 32 Mhz Cristal to a nRF51822??

Thanks

[Stian Røed Hafskjold]

I don't think it is a definitive answer for that, except that i believe Mbed would be slower because it is higher level. Both in Keil and GCC you have optimization options:

gcc.gnu.org/.../Optimize-Options.html

www.keil.com/.../uv4_dg_adscc.htm

In Keil you have the -Otime optimization, which will optimize for execution time. But, in the end I believe you just have to test, because it depends on your code.

You can use a 32MHz crystal, but the chip only runs on 16MHz anyway. It just divides the clock.