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Overclocking: My own visit — Parallax Forums

Overclocking: My own visit

Oldbitcollector (Jeff)Oldbitcollector (Jeff) Posts: 8,091
edited 2008-04-27 04:26 in Propeller 1
I finally broke down stripped several old motherboards & modems with my heatgun.
(If you do this, only do it outside and well ventilated.)

Among the parts I salvaged were several 14mhz and 25mhz crystals.
It appears that I have a prop running Graphics Demo with the 14, (black & white)
with the following settings.

  _clkmode = xtal1 + pll8x
  _xinfreq = 14_000_000



Unless my math is wrong it looks like I've got a nice 112MHZ running.
I know I'm not the first to try this, but are there other side effects that
I may experience due to pushing the Propeller this hard?

The 25MHZ test is next.... [noparse]:)[/noparse]

OBC

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New to the Propeller?

Getting started with the Protoboard? - Propeller Cookbook 1.4
Updates to the Cookbook are now posted to: Propeller.warrantyvoid.us
Got an SD card? - PropDOS
A Living Propeller FAQ - The Propeller Wiki
(Got the Knowledge? Got a Moment? Add something today!)

Comments

  • SapiehaSapieha Posts: 2,964
    edited 2008-04-26 21:38
    Hi Oldbitcollector

    In my tests 14.318000 MHz xtal from PC grapihc cards funktion ok.

    Bat problems start with 15.000000 MHz

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Nothing is impossible, there are only different degrees of difficulty.

    Sapieha
  • Oldbitcollector (Jeff)Oldbitcollector (Jeff) Posts: 8,091
    edited 2008-04-26 22:18
    Ok, Some updates.. {Edit: Corrected as per Sapieha's next post!}

    Either the 25Mhz idea was a bust, or I didn't set it correctly. Back to the 14.3mhz crystals.

    Yes, the motherboards that were scrapped had onboard video cards, hence the 14.3mhz speeds.

    Using the following settings, I've found the proper tweaks for both the Parallax TV Driver (used in Graphics Demo)
    as well as AiGeneric text driver (used in PropDOS)

    First, heres the speed settings.
      _clkmode = xtal1 + pll8x
  _xinfreq = 14_318_000



    Then find the "NTSC color frequency' setting in either driver. By default it will be: 3_579_545
    (It's near the top of the TV driver and AI_Generic_TV)

    Change the number to: 3_579_500

    I can't speak for the PAL users, as all I have is NTSC gear, but it's holding up well over the last hour,
    fast, and the color is right on.

    This information will likely find it's way to the Warrantyvoid site, in the Propeller Cookbook.

    OBC

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    New to the Propeller?

    Getting started with the Protoboard? - Propeller Cookbook 1.4
    Updates to the Cookbook are now posted to: Propeller.warrantyvoid.us
    Got an SD card? - PropDOS
    A Living Propeller FAQ - The Propeller Wiki
    (Got the Knowledge? Got a Moment? Add something today!)

    Post Edited (Oldbitcollector) : 4/27/2008 12:00:41 AM GMT
  • SapiehaSapieha Posts: 2,964
    edited 2008-04-26 23:10
    Hi Oldbitcollector

    XTal on PC cards is 14.318000 / 4 = 3_579_500

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Nothing is impossible, there are only different degrees of difficulty.

    Sapieha
  • Oldbitcollector (Jeff)Oldbitcollector (Jeff) Posts: 8,091
    edited 2008-04-26 23:16
    Perfect! Thanks!

    OBC

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    New to the Propeller?

    Getting started with the Protoboard? - Propeller Cookbook 1.4
    Updates to the Cookbook are now posted to: Propeller.warrantyvoid.us
    Got an SD card? - PropDOS
    A Living Propeller FAQ - The Propeller Wiki
    (Got the Knowledge? Got a Moment? Add something today!)
  • bambinobambino Posts: 789
    edited 2008-04-26 23:47
    OBC,
    Typically, what is the ambient temperature where you are testing this?
    I live in georgia, where it's common to see the air-conditioning switch to heating and back ,in the same day, this time of year!
  • Oldbitcollector (Jeff)Oldbitcollector (Jeff) Posts: 8,091
    edited 2008-04-26 23:56
    Local outside temp is 62f, my house is somewhere around 70f.
    I'm powering the Propeller with 7.5v DC

    By touch, I've detected no increase in temp in either the Propeller itself or the regulators.
    Sorry, I can't be more scientific than that..

    OBC

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    New to the Propeller?

    Getting started with the Protoboard? - Propeller Cookbook 1.4
    Updates to the Cookbook are now posted to: Propeller.warrantyvoid.us
    Got an SD card? - PropDOS
    A Living Propeller FAQ - The Propeller Wiki
    (Got the Knowledge? Got a Moment? Add something today!)
  • bambinobambino Posts: 789
    edited 2008-04-27 00:59
    That's the technical answer I wanted. I use the swag method myself sometimes (" Scientific Wild *** Guess")
    Basically, I was wondering if you were having to use a Heatsink of some kind to keep it cool.
  • hippyhippy Posts: 1,981
    edited 2008-04-27 01:16
    My 7,372,800 Hz XTAL + PLL16x @ ~20C has been running fine for over a week now with no problems ( 118MHz ). As with the 14.3MHz, it's keeping the system clock under 120MHz which seems to be the magic success factor.

    I didn't have any success with the 14.3MHz I tried previously but will go back and give them a re-test in case I configured something wrong. I'll report back.

    I bet I tried using PLL16x last time. Using 14.3MHz + PLL8X @ ~20C and there was no problem in my short tests. I'm quite surprised because that's 43% over the 160MHz PLL rating.

    10.24MHz and 12.288MHz also worked at PLL8x.

    Post Edited (hippy) : 4/27/2008 1:50:01 AM GMT
  • Lord SteveLord Steve Posts: 206
    edited 2008-04-27 04:26
    If I may add my 2 cents:· I have been running my DIP package Propeller at 100Mhz (6.25 MHZ + PLL16X) for a week now with zero problems.

    I love it.· Man, I love it.
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