[vdr] Re: Increasing SDRAM on DVB cards

[Hermann Gausterer <mrq1@gmx.net>]

after some mandatory sport i am back again ;-)

in the meantime, i have studied the pdf of the av711x

some NEWS ;-)

> > SCS1 ? 0xCC00 0000 - 0xCC1F FFFF
> > SCS2 ? 0xCC20 0000 - 0xCDFF FFFF
> > so each has a range of 2Mbyte

if you look closer, you can see that the second space is
much greater the the first, the first is equal to 2Mbyte
but the second is equal to 32Mbyte

but the docu speaks only from 16mbit rams .. so this is
inconsistent .. but that does not disturb me at the moment

next on page 20, we see the memory layout of an PAL chip
(looks quite simular to my guesed one ;-)

and from this layout we can extract real new INFO :-))

we see that the lower array is used for audio and video
the higher for osd ...
but whats new here .. new is that the second array
the OSD .. is selected with the, in the meantime "famous"
SCS2 line ;-) (page 19 says this)

so ... what can we do here? we can only extend the OSD
memory and nothing more . and that to a maximum of
32 Mbyte .. and i think that is enough for a true color OSD ;-)

so again, we can nothing more and nothing less do then search
for an pin-compatible 64 mbit chip and solder it to the board

we cannot do anything like an external adressdecoder we all
learned at school, because the ram is adressed with a
timemultiplexed adressbus (row & column)

there are ENOUGH adresslines solderd to the chip
the real problem is to find another chip .. ore the hard way
make an riserboard with an complitly different dram chip
and solder it with wires to the right pins 

> Well, thanks for pointing out this page - I guess I must have been
> blind so far, not to have seen this...

it is now the first time i was looking to this docu ;-)

> So basically this means that we definitely need access to SCS2, otherwise
> we can flat out forget about this.

again:
the scs2 is allready routed to the osd ram chip ... i hope the 
HY57V161610D is the one used for OSD and not the other
but i read today somewhere which chip is used for what

hermann

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