Maximum clock speed for the propeller

EyalMEyalM Posts: 2
edited 2009-11-10 - 15:16:36 in Propeller 1
I'm designing a very fast tracking system based on the propeller. For the moment I use 5MHz external crystal and x16 PLL. There are a lot of FP calculations and I would like to speed up the system.
What is the actual tested internal clock of the propeller? By the specification it looks like I can connect an 80MHz external crystal, set the clock mode to XTAL3 + x16PLL and theoretically get an internal clock of 1.28GHz. Is that correct and allowed for the propeller?
If the answer is yes, what is the impact on current consumption and heat dissipation of the chip, does it need cooling?



  • BeanBean Posts: 8,041
    edited 2009-11-10 - 13:04:55
    No. I think about 120MHz is the max without special cooling.

    I would recommend you try to eliminate as many floating point operations as possible by using integer or fixed point math instead.


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    Does that byte of memory hold "A", 65, $41 or %01000001 ?
    Yes it does...

  • localrogerlocalroger Posts: 3,269
    edited 2009-11-10 - 13:05:15
    Eyal, you can't push the prop nearly that fast. There are people regularly pushing 100 MHz with 6 MHz crystals and some claim to have pushed it to 120 MHz with cooling, but much beyond that neither the PLL nor the cog cores themselves will work at all.
  • mctriviamctrivia Posts: 3,772
    edited 2009-11-10 - 13:06:56
    i beleive the fastest people have goten it running at is 130Mhz or so.

    6.25 * 16 = 100Mhz has been shown to be very stable.

    24 bit LCD Breakout Board coming soon. $21.99 has backlight driver and touch sensitive decoder.
  • Mike GreenMike Green Posts: 22,919
    edited 2009-11-10 - 14:41:45
    During the testing to develop the Propeller datasheet information, there were experiments made to test the maximum operating frequency of the Propeller at different temperatures and operating voltages. The results are given in the datasheet in graph form on page 31. Download it and have a look.
  • StefanL38StefanL38 Posts: 2,287
    edited 2009-11-10 - 15:16:36
    virtual multiplying is so easy - but the reality is so hard ....
    [x] <== SLAM in nail here to hook up the new screen! :lol:
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