ST HDMI Out

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alexh
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Re: ST HDMI Out

Post by alexh »

DrCoolZic wrote:Apparently one key element to succeed is to to have an Atari with a modulator. Unfortunately this type of machine was never released for STE in France :(
Presumably this is because without a modulator you have separate HSYNC and VSYNC and no CSYNC?

This board has been used in the Amiga community just recently with some success

http://timeharvest.net/new-arrival-cga- ... p-706.html
Guest

Re: ST HDMI Out

Post by Guest »

http://www.keene.co.uk/av-distribution/ ... rough.html
here is a £60 version of the same thing
some cable boxes have TWO scart sockets i and o
and an hdmi output
although they will NOT scale but this box will
the crap small amount of P an atari has to 720p atleast...
as a tv signal is only scalled at the TV not the converter
so your TV switches mode to scale
even hdmi detects 720 or 1080
the above converter maybe £60 youll find it cheeper on fleebay
but it does the job VERY WELL
and works already
if you have several machines to run on one monitor
it also has pass thru to all hdmi or RGB thru it also
so several machines can be used without any cable changes
and i feel this is what pisses people off the most
i just use four monitors and use cheep 15" LCD for the falcon and TT
i dont need much
but hdmi??
1080p your pixels are like oxo cubes and the screen swims in sync soup
its a simple flag signal to tell a TV to switch to 1080p a tv doesnt detect the mode other than the flag present
bit like the stereo led comes on if the FM detected signal has a 19khz subcarrier
because it is usually interlaced as bigger pixels blocks in blocks again after frame store reinterlaced
so it looks poo.... brurry and not sharp
youll beg for an old sony trinatron and scart,,
i get it
this is a topic for making one just too make one perhaps that can fit inside
but its like to reinvent the wheel..... this box will fit inside
if you change the psu for a micro atx psu
why cant the makers of fgpa glory just sign an NDA and ask the makers for the code
this box guy uses????
usually if your credible and promise not too share youll get it
ive done this in the past,.,,

i just dont why to tie up a 700mhz fpga etc etc what ever
to do this menial task
and spend like heaps of time to get it right
decoding and recoding non interlaced video and the latency it introduces
so its NOT the same experience than playing the machine on a RGB non interlaced in time frame monitor or projector via svideo
if you add an adapter you add latency so you turn your response into a few bits less
etc etc
waist of time where video is concerned
the only way is too ask me nicely for my C++ shifter ic dll
then you can turn it into a C .lib and inc it ...
very easy i have software too do the exchange...
i so far have modeled the shifter at 16mhz and the DMA ic
although the code will need some tweaks it works
the back end data registers interaction etc of the shifter must be retained
but an FPGA chip that REPLACES the shifter or gst shifter
while retaining the original function is important
so all i/os of the shifter are preserved and the back end video data exchange from 4 or 5 bit to hdmi scalled to 720p
so... use a riser dil with an fpga on it and ports
i can draw this up in a few hours....!!!!!

lets face it to replace the shifter in an ste or mega ste takes smd work
to convert the video here adds latency and several layers of rubbish
ie you would need to strip to D-A R2R on the output of the gst shifter and serialize it ... to 5bit by 3 block transfer
and recover the clocks needed to do this exchange

to do the same to an st or mega st take replacing the shifter only with a dil FPGA
so its worth it
but only by replacing the shifter ic as data from it isnt wide enough and needs centered {shifted left }and padded

above all you cant polish a turd and even 720p on hdmi will look terrible and not sharp
Guest

Re: ST HDMI Out

Post by Guest »

a hardware hack to change the glue made up frequencies is a better idea using a GAL to the hires 19khz range
then you can have 3 colours in a quadrant of the normal VGA picture
then scale it using an fpga chip perhaps... interlacing it take a frame store in sram or dram
and this also takes control of said chips
with simple mods to the frequencies you can get your fpga translation much easier
like 15khz and not 15.4 and 20khz and not 19 easier for conversions and less interpolation
now VGA complient then mod it to hdmi ffs too much time waisted
if i remember if you switch to hires then you get all three colours anyway but lack of sync

what ever way you need to use higher sync regen perhaps using a pll and dual pll to get 19khz..

:P

st only mod this

ste or mega ste with gstshifter smd is only converted by recovering the digital colour data at the shifter pins to the R2R rgb driver

padding it proplery and shift it left to allign it in 3 x5 bit blocks.. as 3 bytes... so 3 bytes non interlaced frames so you need a frame store to reorder the frames then output them a little later...
its to do with signed and unsigned bytes data...
you can do it in pure code without a frame store
as a thread on a brigade line and pluk off the interlaced bytes... to an array set

so fpga shifter replacement is only an option for st and mega st

if you want any help if i can i will
wietze
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Re: ST HDMI Out

Post by wietze »

Is this project still alive? Its been a good while since we last heart from the author :(
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