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KEA8 clock configuration

Question asked by Alessio De Marchi on Nov 22, 2016
Latest reply on Dec 2, 2016 by Mark Butcher



I'm working with TRK-KEA8 board and try a simple toggle pin main cycle:


GPIOA_PTOR |= 0x00010000;   // LED toggle


with ICS configuration as FEI 40MHz and 20 MHz bus frequency:


ICS_C1 |= ICS_C1_IRCLKEN_MASK; /* Enable the internal reference clock*/

ICS_C3 = 0x90; /* Reference clock frequency = 31.25 KHz*/
while(!(ICS_S & ICS_S_LOCK_MASK)); /* Wait for PLL lock, now running at 40 MHz (1024 * 39.0625Khz) */
ICS_C2|=ICS_C2_BDIV(1); /*BDIV=2, Bus clock = 20 MHz*/


I'm expecting a two edge of LED toggle time less of 100 ns, bus I see about 800 ns of main cycle time.

What's wrong?


Alessio De Marchi