Dieter wrote:
The TMS320DM6446-594 is supposed to do HD-TV and has a TMS320C64x™ DSP
clocked at 594 MHz.
So, perhaps the issue is that the CPU needs to be a DSP.
This looks promising. Being programmable, new codecs would not require
new hardware. (Unless you needed a faster DSP.)
The bad news is that they are expensive. I am not that familiar with
TI's DSPs. More exploration is needed but I find that this is a 32 bit
bus 600 MHz: TMS320C6418 costs $50.30 or $56.00 depending on the package
(ZTS or GTS) in 1K quantities.
OTOH, I wonder how much of a graphics board could be implemented with
such a chip.
Yeah, they cost more than I'd like, (the 6446 is US$47.85) but it looks
like they have nearly everything onchip.
In fact, it looks like it might be easier to build a standalone box
with this thing than an expansion card. It already has Ethernet
and the DSP can do general purpose stuff. Add RAM and glue. Maybe
additional ROM. Put it in a box. Add a wall wart p/s.
I haven't found a max power rating yet, but the numbers I have found are
like 1.5 Watts, so probably 2 Watts or so worst case. Is that low
enough that we could just heat sink it to an aluminum box and not need
a fan?
Any codec patent issues get moved from hardware to software.
I'm not saying it is perfect, but I see a lot of advantages. It is
programmable, but costs a lot less than a FPGA. It uses less power
than a FPGA. No gazillion dollar ASIC mask. It looks like what we
have been looking for: a documented graphics chip.
Did you also look at the TMS320DM643? 600 MHz with 64 bit bus but only
supports 133 MHz SDRAM for memory. One would hope that they will come
out with one that can use 200 MHz DDR2 SDRAM and perhaps an HPI that
will run at 66 MHz. This one appears to have a limit of 50 MHz which
would mean only 33 MHz x 32 bit system bus when accessing its RAM but
that is fast enough to read in compressed video.
IAC, this has the video refresh controller and sync generator but
requires an external RAMDAC. Small problem since nobody makes them anymore.
I presume that this could run the scan converter in software.
--
JRT
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