Shop OBEX P1 Docs P2 Docs Learn Events
SD write speed — Parallax Forums

SD write speed

BasilBasil Posts: 380
edited 2008-09-08 20:44 in Propeller 1
Hi All,

I'm sure Ive seen a thread on this around but I cant find it for the life of me!

How fast can one write to a micro SD using the library SD routine?

I need to write 3 byte 200 times per second.

I also need to know how fast I could write 600 bytes (in ms)

Any links appreciated [noparse]:)[/noparse]

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
-Alec

My our page

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2008-09-08 14:54
    Look at the FAT File System object in the Object Exchange (here: obex.parallax.com/objects/92/).
    The documentation quotes some transfer speeds (in bits / second). Note that this speed is dependent on the speed
    of the SD card itself, but is way beyond what you need.
  • BaggersBaggers Posts: 3,019
    edited 2008-09-08 15:27
    Basil, you'd also be better off writing in 512byte chunks, so pad 600 bytes out into 1024 bytes, when you write, that way, it doesn't cross sectors, and need multiple accesses.
    you should also easily do 1024 bytes per second, with time to spare [noparse];)[/noparse]

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    http://www.propgfx.co.uk/forum/·home of the PropGFX Lite

    ·
  • rjo_rjo_ Posts: 1,825
    edited 2008-09-08 17:35
    Basil,


    The only uSD card I have is hooked up to an old 4D Systems uoled-prop-96.... which is limited to 64mhz.

    Using Spin only, i was able to write about 20000 individual characters per second.

    A word of warning to my lazy American counterparts ... New Zealanders are a lot like the Brits when it comes to productivity... when they show up, it is time to get back to work[noparse]:)[/noparse]

    Rich
  • jazzedjazzed Posts: 11,803
    edited 2008-09-08 18:01
    Rich,
    Considering the great wines coming out of Marlborouh, I can understand the drive to get the job done so you can enjoy your time off [noparse]:)[/noparse]

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    --Steve
  • Beanie2kBeanie2k Posts: 83
    edited 2008-09-08 18:04
    rjo_ said...
    Basil,

    ...
    A word of warning to my lazy American counterparts ... New Zealanders are a lot like the Brits when it comes to productivity... when they show up, it is time to get back to work[noparse]:)[/noparse]

    Rich

    Hmmm... That's a new one on me. rolleyes.gif I thought the rest of the world thought we were a bunch of workaholics.
  • ElectricAyeElectricAye Posts: 4,561
    edited 2008-09-08 18:21
    rjo_ said...
    New Zealanders are a lot like the Brits when it comes to productivity... when they show up, it is time to get back to work[noparse]:)[/noparse]

    Rich

    I guess "when" is the key word here. There's always that 6 month "holiday" that seems to slow things down a wee bit.

    devil.gif
  • rjo_rjo_ Posts: 1,825
    edited 2008-09-08 19:15
    Holidays are what the Prop was made for[noparse]:)[/noparse]
  • BasilBasil Posts: 380
    edited 2008-09-08 20:44
    Lol, thanks for the answers firsty [noparse]:)[/noparse]
    Baggers, Im trying to replace a dataflash chip so what you have suggested makes complete sense [noparse]:)[/noparse] Ill put the 2 buffers inside the prop
    ElectricAye said...
    I guess "when" is the key word here. There's always that 6 month "holiday" that seems to slow things down a wee bit

    Noone told me about a 6month holiday!?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    -Alec

    My our page
Sign In or Register to comment.