[coreboot] Yet another idea of an SPI flash chip programmer

[FENG Yu Ning]

On Tue, Dec 23, 2008 at 10:40 PM, Peter Stuge <peter at stuge.se> wrote:
> I wonder how easy these are to order..

I did not post this because I felt it was like advertising, but here it is:

  http://www.dediprog.com/SPI-flash-accessories/SPI-Flash-Socket-8pin

I have contacted with the company and I am told the MOQ is 10.
Shipping fee is high except for Taiwan.

> I know that 1 second would be ideal, but what would be good enough?
>
> 30s? 1min? 2min? 3min?
>
> And for which flash chip size? That is also important, because double
> the size will double the time. :) 4Mbit vs. 16Mbit = 4x the time.

Could the words, between parentheses after "not slow" in my original
post, serve as a specification of that kind?
I think what I meant in the original post is I do not want to wait for
more than 3 mins for any chip. Of course that is not a proper spec.
Since 8Mbit chips are widely used these days (is it?), my spec would
be: 3 mins - 8Mbit.

> Please do. The 2232 MPSSE mode's maximum SPI clock is 6MHz, but the
> problem is with turnaround time between each sequence of bytes that
> are read or written. ..., this need for status reads can slow the
> process down quite a lot.

I did not realize that. Let's see.

> Another option is to download the data to be flashed "just in time"
> so that no buffering is needed. But then the PC communication link
> needs more care. I think that is easier than adding RAM however.

After all, a (not so) fast GPIO peripheral interface, with a simple
(stupid) protocol, solves the problem. The philosophy of PC decides we
do not have things of that kind.

  Serial and parallel ports are simple, but they are a bit slow.
  USB is fast, but the protocol is complicated (for SPI programming
application).

> I'm looking forward to hearing more about this. When your programmer
> is finished we should look closer at how to make plugins for
> flashrom.

Sure. I am looking forward to coding again.


yu ning