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CCS4 PLL multiplier limitation to 10

Cristian Bogus
Prodigy 140 points

          I'm using CCS4.1.1.00014 with a F28335 experimenter kit (20MHz oscilator). I would like to use the F28335 at 150MHz (PLL multiplier or 15, divider of 2). However, in CCS the FLASH programming tool limits the multiplier at 10. A PLL multiplier of 15 is simply NOT AVAILABLE!

Is there any problem if the F28335 chip is configured to work with a 150MHz frequency (PLL multiplier of 15, divider 2) but the FLASH programming is made with a PLL multiplier limited at 10?

Is there any problem in using a PLL multiplier of 15 as long as the 150MHz frequency is not exceeded? 

Regards,

Cristian

  • 0
    TI__Guru* 91970 points

    Cristian Bogus said:

              I'm using CCS4.1.1.00014 with a F28335 experimenter kit (20MHz oscilator). I would like to use the F28335 at 150MHz (PLL multiplier or 15, divider of 2). However, in CCS the FLASH programming tool limits the multiplier at 10. A PLL multiplier of 15 is simply NOT AVAILABLE!

    Is there any problem if the F28335 chip is configured to work with a 150MHz frequency (PLL multiplier of 15, divider 2) but the FLASH programming is made with a PLL multiplier limited at 10?

    Is there any problem in using a PLL multiplier of 15 as long as the 150MHz frequency is not exceeded? 

    Regards,

    Cristian

    Early 2833x control cards used a 20MHz clock so that the user would only need to make a few changes to any F280x software (runs at 100MHz) when ported to F2833x parts. It was only after production began that the developers realized that the 15x PLLCR setting is not supported (ref www.ti.com/lit/SPRS439).  

    Note: while the PLLCR will allow you to set this value, it is not supported and may not yield a robust design.

    Controlcards now shipping have the 30Mhz.   If you want to replace it yourself a known 30MHz replacement is part # 644-1043-1-ND from Digikey. The PLL multiplier setting (PLLCR) would then be 0xA.

    Sorry for any confusion this has caused.

    Please also see this related post: http://e2e.ti.com/support/microcontrollers/tms320c2000_32-bit_real-time_mcus/f/171/p/21462/82956.aspx#82956

    -Lori