4-bit SD interface?

RaymanRayman Posts: 10,063
edited 2013-03-22 - 09:28:47 in Propeller 2
I've said in the past that 4-bit SD interface seemed to make more sense for P2...
Lonesock also meantioned that the speed up wouldn't be that great on P1.

I just took another look at the SD web site and some wiki pages and the legality of using 4-bit interface is still a little murky to me.
Actually, the legality of using the SPI interface also looks murky.
There is nothing there that says it's OK to use the SPI interface without a license...

So, appears to me that using a 4-bit interface is just as wrong as using a 1-bit interface...

It's pretty easy to find some 4-bit C code on the internet. You'd think the SD association would have shut that off, if it really were a problem...

Plus, I've read that Linux includes 4-bit access code (although I couldn't find the actual code).

Anyway, I think I'm going to plan on using all 4 bits on my first Prop2 board...

Comments

  • SapiehaSapieha Posts: 2,964
    edited 2013-03-22 - 06:53:12
    Hi Rayman.

    I don't think it is any problem to use it.

    DE2-115 come with 4-Bit interface to SD and all necessary "C" programs to run that.

    Rayman wrote: »
    I've said in the past that 4-bit SD interface seemed to make more sense for P2...
    Lonesock also meantioned that the speed up wouldn't be that great on P1.

    I just took another look at the SD web site and some wiki pages and the legality of using 4-bit interface is still a little murky to me.
    Actually, the legality of using the SPI interface also looks murky.
    There is nothing there that says it's OK to use the SPI interface without a license...

    So, appears to me that using a 4-bit interface is just as wrong as using a 1-bit interface...

    It's pretty easy to find some 4-bit C code on the internet. You'd think the SD association would have shut that off, if it really were a problem...

    Plus, I've read that Linux includes 4-bit access code (although I couldn't find the actual code).

    Anyway, I think I'm going to plan on using all 4 bits on my first Prop2 board...
  • tonyp12tonyp12 Posts: 1,950
    edited 2016-08-12 - 16:54:53
    I say go for it, as you don't need a license to use the connector and I can not see that they will tell you to not use all 4 traces on the pcb.
    As the user is supplying the software, I would assume they don't go after individual users.
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