[En-Nut-Discussion] Timing on AVR32

[Daniel Fiedler (Ethernut)]

Hello,

i have read back the PLL Control register of PLL0:

It's hex value: 0x10 0x09 0x01 0x0D

PLLMUL is set to 9
PLLDIV is set to 1

PLLOPT[0] uses 80 ... 180MHz range
PLLOPT[1] selects f(pll) = f(vco)/2

With these options f(pll) is calculated: 
f(vco)= ( 9 + 1 ) / 1 * f(osc) = 120MHz
f(pll) = 60MHz

Seems to be correct. 

In file /nut/arch/avr32/dev/ostimer.c I found this function.

void NutRegisterTimer(void (*handler) (void *))
{
    /* Set compare value for the specified tick frequency. */
//    Set_system_register(AVR32_COMPARE, NutGetCpuClock() / NUT_TICK_FREQ + Get_system_register(AVR32_COUNT));
	Set_system_register(AVR32_COMPARE, NutGetCpuClock() / NUT_TICK_FREQ );

    sig_sysCompare.ir_handler = handler;

    register_interrupt(SystemCompareIrqEntry, AVR32_CORE_COMPARE_IRQ, AVR32_INTC_INT0);
}

I changed line 4 in line 5. Now system seems to run at the correct speed. 
But Nut/os needs about 15-20s for boot/init. 

Could someone explain this function?


Best regards
Daniel

-----Ursprüngliche Nachricht-----
Von: en-nut-discussion-bounces at egnite.de [mailto:en-nut-discussion-bounces at egnite.de] Im Auftrag von Ethernut
Gesendet: Mittwoch, 16. Mai 2012 12:36
An: Ethernut User Chat (English)
Betreff: Re: [En-Nut-Discussion] Timing on AVR32

Hi Ole,

yes i think this too. I use the EVK1100. 

I'm new to Nut/os so i don't have figured out how board init works exactly yet.

An other possibility:
I have read something about a System Timer with 1ms. This Timer could Maybe to Slow.

Greetings
Daniel

Von meinem iPhone gesendet

Am 16.05.2012 um 12:05 schrieb Ole Reinhardt <ole.reinhardt at embedded-it.de>:

> Hi Daniel,
> 
>> I have written an Time-Clock for AVR32. I used an NutTimer with 
>> 1000ms timing. But clock counting is twice to slow.  I also created a 
>> BlinkingLed Thread. With a NutWait command with 150ms wait time but LED blinks slowly.
>> I resume the clock frequency of cpu is set not correctly. Or the 
>> system timer of nut/os is to slow.
> 
> I've never worked with the AVR32 plattform yet, but it sounds like a
> (wrong) PLL or Clock source setting issue. 
> 
> Do you use one of the supported development boards or an own setup?
> 
> bye,
> 
> Ole
> 
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