primax: Thread: D600

Yet more investigation as to why the D600 won't scan at 600 DPI...

I had originally put this down to a timing or throughput problem, but I have 
now repeated the tests on 3 sets of hardware (P90, K6+ 400 and Athlon 1400) 
and all have similar results.

Also the new libieee1284 version exhibits the same problem, so I don't think 
that it can be timing.

Having put in extensive diagnostic statements, I am still at a loss to see 
where things are going wrong. The scanner simply scans the first through 
lines and then refuses to output the bit pattern needed to exit the first do 
loop in get_scan_data ().

It seems that the scanner is never filling the FIFO with the necessary data 
for the next scan line.

However it isn't at all clear for the reason. For example an image 2 inches 
wide (command line param -d 2x11.5) will work okay at 600dpi, but not an 
image 4 inches wide.

Likewise an image 4 inches wide will scan okay at 400dpi.

Another thought was a buffer overflow somewhere, but I can't find it!

So my conclusion is that the D600 has a slightly different internal FIFO 
architecture, or command set. Perhaps it is necessary to scan each line in 
two halves?

I think I have got to the stage whereby the only way to make this work is to 
get hold of the Primax documents. So if anyone on this mailing list has a 
copy I would be very grateful to receive it.

Best regards,

Mike Rothon.

On Thu, Jan 02, 2003 at 09:37:00PM +0000, Mike Rothon wrote:
> Yet more investigation as to why the D600 won't scan at 600 DPI...
as the D600 only supports 600x300dpi (and not 600x600), 600dpi scanning
is not implemented. 300dpi should work fine instead.

-- 
Christian Ordig
Germany

> as the D600 only supports 600x300dpi (and not 600x600), 600dpi scanning
is not implemented. 300dpi should work fine instead.>

Just to be sure, are you saying that the D600 won't work at 600dpi
(according to Primax it supports 600x1200dpi optical) or that the
primax_scan program doesn't support 600dpi scanning on the D600?

I appreciate that the 1200dpi optical claim is a function of the stepper
motor drive, but presumably it should be possible to send the correct values
to get this to step at maximum resolution.