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Topic: Overclocking the Arduino DUE (Read 624 times) previous topic - next topic

janost

Thought I try some DUE overclocking just for the fun of it :)
So I tried some different PLL MUL/DIV settings.

It seem that 120MHz is max what the SAM3X8E Cortex M3 chip will run.
This is not because of the flash read speed but because of the internal SRAM and that has no waitstate setting.

So at 114MHz it runs stable with the original 4FWS setting (20MHz AHB bus-speed).

That is 136% overclocking without any problems.

Code: [Select]

#define SYS_BOARD_PLLAR (CKGR_PLLAR_ONE | CKGR_PLLAR_MULA(18UL) | CKGR_PLLAR_PLLACOUNT(0x3fUL) | CKGR_PLLAR_DIVA(1UL))
#define SYS_BOARD_MCKR ( PMC_MCKR_PRES_CLK_2 | PMC_MCKR_CSS_PLLA_CLK)
       
/* Set FWS according to SYS_BOARD_MCKR configuration */
EFC0->EEFC_FMR = EEFC_FMR_FWS(4); //4 waitstate flash access
EFC1->EEFC_FMR = EEFC_FMR_FWS(4);

/* Initialize PLLA to 114MHz */
PMC->CKGR_PLLAR = SYS_BOARD_PLLAR;
while (!(PMC->PMC_SR & PMC_SR_LOCKA)) {}

PMC->PMC_MCKR = SYS_BOARD_MCKR;
while (!(PMC->PMC_SR & PMC_SR_MCKRDY)) {}

prismatics

Thanks for sharing this valuable information. It's interesting to see that you can reduce power consumption down to 20% by lowering the processor clock speed to some MHz. This can be very interesting for low power battery-operated devices as you can recover the full processor speed in some microseconds... Additionally, disabling all unused peripherals can lead to even lower power consumption and greater battery life without losing any functionality.

janvier123

can this be used on a UNO too  or is it not possible ?
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robtillaart

No not the same as UNO and DUE are completely different processors.

That said, there have been many overclocked UNO's  google is your friend)

Saving power with an UNO is well described here - http://www.gammon.com.au/forum/?id=11497 
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

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