[Coco] Introduction

[Mark McDougall]

On 25/02/2013 2:10 PM, John Kent wrote:

> Dave Vanden Bout from XESS has released an IP core for talking to an SD
> card on the XuLA2 board.
> I'm not sure if it's just an I2C or SPI driver or if it has more in it to
> read and write sectors.
> I find CF cards easier to use, but I suspect they are being phased out.
> They are much bulkier than SD cards.

My colleague's core runs in parallel mode, not SPI. SPI's quite easy to
use and I believe there's a number of SPI cores available - but they
require state machines and are more suited to be bit-bashed from a
soft-core micro. Besides, he wanted the challenge of doing a 'proper' core...

I agree for CF; I first emulated the Cloud9 SuperIDE controller using the
opencores OCIDE controller on a board with CF. When I ported the design to
the DE1, I wanted to keep the existing code in-tact so I wrote what is
effectively an IDE<->SD interface. Because my colleague's core had quite a
simple and "raw" interface, it was easy to hook onto the back of the IDE
controller. I also did the same on the TRS-80 Model I implementation.

Regards,

-- 
|              Mark McDougall                | "Electrical Engineers do it
|  <http://members.iinet.net.au/~msmcdoug>   |   with less resistance!"