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What Is the real CCLK referenced ? (used for IAP and FlashFS)

Hardware : MCB2300 Board (LPC2378)
Xtal : 12Mhz

I read on some post that the CCLK to set in the IAP code is 12000 (KHz)
http://www.keil.com/forum/10740/

When I give a look at the LPC_IAP2_512 project in the fs_init() function I see that for LPC23XX devices CCLK is set to 4000 (KHz)

But I think that conforming to the user manual §4 fig 16 the CCLK is CPU clock after going from Xtal (if selected) * PLL * CPU Clock divider.

If I look at the default config in LPC2300.s I see that the PLLCFG Multiplier is 12 and divider is 1, and the CCLKCFG divide by 6.

So

CCLK = (1/6) x (12/1 x 2) * XtalCLK = 4 x XtalCLK
Freq(CCLK) = 1/4 Freq(Xtal) = 3 MHz


So we should put in the IAP fs_init() or IAP routines CCLK = 3000. Right ?
Or this CCLK is not the "user manual definition".

Parents
  • So low value when the spec says that the uc can work up to 72 MHz let me think I missed something :

    After reading DEEPER I found the following text in the doc §4.4.2 : "... The ARM processor clock frequency is referred to as CCLK".

    So we are talking in terms of frequency :

    CCLK = (1/6) x (12/1 x 2) * XtalCLK = 4 x XtalCLK = 48 MHz
    

Reply
  • So low value when the spec says that the uc can work up to 72 MHz let me think I missed something :

    After reading DEEPER I found the following text in the doc §4.4.2 : "... The ARM processor clock frequency is referred to as CCLK".

    So we are talking in terms of frequency :

    CCLK = (1/6) x (12/1 x 2) * XtalCLK = 4 x XtalCLK = 48 MHz
    

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