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TAQOZ - Tachyon Forth for the P2 BOOT ROM



  • jmgjmg Posts: 11,673
    TAQOZ itself is now frozen in ROM and Chip is making images available. I've attached the combined source and listing.

    Great :)

    Is there a table yet, of the various boot-paths and boot times for each ?
    There were comments about making boot faster ?

  • Peter JakackiPeter Jakacki Posts: 7,466
    edited May 30 Vote Up0Vote Down
    Unfortunately, the SD boot is not that fast because it is meant to be callable and so runs in hubexec mode which slows things down because of a tight loop. If it is called at full clock speed it won't be so bad but the booter however could load a 2nd stage minimal SD booter which could operate from cog at 2.5MHz SPI speeds even at 20MHz clock rate but of course could switch to a 200MHz clock and run at 25MHz SPI speeds. So that would make 2 stage SD booting very fast. This is also how Chip has the SPI Flash working, as it is meant to load in a 2nd stage that can then ramp up the clock etc.

    TAQOZ itself runs separate SPI read/write routines in cog so even at 20MHz the SPI speeds are 2.5Mhz.

    BTW, the 2nd stage loader is probably the way most code will end up loading as we explore the P2 and find better ways of doing things. If we could use the smartpins for SPI bus I think we can access SD at 50MHz SPI speeds as the old standard back in 2003 specified 25MHz max but IIRC this was upgraded to 50MHz.

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  • ErNaErNa Posts: 1,090
    "how ingrained our thinking becomes because that is how we are so used to writing programs"
    That gives hope. Our thinking is not ingrained, it becomes ingrained. And that can be changed. We have to adapt our successful thinking to programming. First look into your purse: 300$, then spend the money. Not spend (300), then realize, nothing to spend!
    The world mist the train when HP overprized the HP35 and TI introduced the cheap "scientific calculators for pupils".
    The advantage now is: tachyon in frozen in silicon and there will always be a fallback when progress comes to fast to keep track ;-)
    Thanks to all for the great work!
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