Atmel studio / GCC - oprimalizace

Jan Waclawek konfera na efton.sk
Středa Duben 1 17:02:50 CEST 2020


Tieto moderne AVRka od Microchipu nepoznam, naposledy som AVRko programoval
pred eeee cojaviem asi 8 rokmi.

Takze stahujem DS, hladam MCLKCTRLA a hned druhy najdenie je

The Main Clock and Prescaler configuration registers (CLKCTRL.MCLKCTRLA,
CLKCTRL.MCLKCTRLB) are
protected by the Configuration Change Protection Mechanism, employing a
timed write procedure for changing these
registers.

Klikatelna linka vedie na
8.5.7.1  Sequence for Write Operation to Configuration Change Protected I/O
Registers
[...]
2. Within four instructions, the software must write the appropriate data
to the protected register.

Cize to treba napisat v asembleri. Bodka.

wek


----- Original Message ---------------

Subject: RE: Atmel studio / GCC - oprimalizace
   From: Pavel Hudecek <edizon at seznam.cz>
   Date: Wed, 1 Apr 2020 16:53:06 +0200
     To: HW-news <hw-list at list.hw.cz>

Tiny414 v kitu explained nano.

Inicializace hodin:

	unsigned char n;

	__asm__("cli");

	// Main clock source: 20MHz Internal RC Oscillator
	// 20MHz oscillator specified by the OSCCFG.FREQSEL fuse bits=0x02
	// Peripheral clock output on CLKOUT (PORTB, Pin 5): Off
	n=CLKCTRL_CLKSEL_OSC20M_gc | (0<<CLKCTRL_CLKOUT_bp);
	CPU_CCP=CCP_IOREG_gc;
	CLKCTRL.MCLKCTRLA=n;

	// Peripheral clock prescaler division ratio: 1
	// Peripheral clock: 20000,000 kHz
	n=0;
	CPU_CCP=CCP_IOREG_gc;
	CLKCTRL.MCLKCTRLB=n;

Takhle to vygeneroval codevision, pùvodnì tam byly ještì ty pragmy mìnící
optimalizaci, ale odmazal jsem je, aby neprudil že je ignoruje.

PH

Od: Jan Waclawek
No dobre ale ake je to vlastne AVR? Daju sa v nom vobec programovo menit
hodiny?




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