LPC55S69 : flash prefetch bit is dropped after PowerDown

[EugeneHiihtaja]

Hello !

I'm setting Flash prefetch bit for accelerate performance.

Testing show that it set to 0 while PowerDown mode.

Is this true ?

Before :

+SYSCON->FMCCR 0xB03A  -> 150Mhz, prefetch ON

After:
-SYSCON->FMCCR 0x101A -> 12Mhz, prefetch OFF

Setting on FMCCCR in BOARD_BootClockFRO12M(); 

done in correct way.

Regards,

Eugene

[Sabina_Bruce]

Hi Eugene,

Could you please confirm the revision of your LPC55S69?

Can you please clarify what testing is done?

Testing show that it set to 0 while PowerDown mode.

Best Regards,

Sabina

[EugeneHiihtaja]

Hi sabinabruce‌ !

Everything is latest. Board revision A2.

When prefecth is enabled it is +25% gain in performance of software cryptography tests.

So prefecth is working if it enabled.

Regards,

Eugene