4-bit SD interface?
Rayman
Posts: 13,892
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...
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
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.
As the user is supplying the software, I would assume they don't go after individual users.