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Oswald
Registered: Apr 2002
Posts: 5094 |
DTV programming
ok, are there any docs / tuts whatever except Jeri's frighteningly cryptic text? Someone can tell Jeri to atleast debug her docs ? (for example: it claims the dtv vic can read 4 bytes while displaying 8 pixels. hows 8bpp mode done then?)
how about collecting them on cswiki (if any)?
I have checked a dtv forum but its mainly about soldering, how can ppl be happy with their modded dtvs, when there's nothing to show off the HW capabilities? :P
Yesterday I was wondering about making a demo for the DTV, but the lack of information scared me away. On what I understand it should be possible to speed up ANY effetct ATLEAST by a 3.3x, but with clever coding one can take it to way much more.. and I havent yet taking into account the DMA& the Blitter... :P
anyone? |
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Scout
Registered: Dec 2002
Posts: 1570 |
tlr posted some of his dtv sources here at csdb.
You might take a look at that.
As for setting up a 256 color 8bpp screen and doing dma memory transfers i can give you some help too.
Another nifty thing of the DTV is the segment mapper; this makes able to map high memory to access it as normal memory.
Take a look at this doc for that: http://picobay.com/dtv_wiki/images/2/28/Segmapper_1c.pdf
I agree about that dtv forum. Too much modding, not much coding.
I can count the total amount of DTV democoders on 1 hand over there ;(
Let's change that =) |
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tlr
Registered: Sep 2003
Posts: 1790 |
So you have a DTV now Oswald?
I'm looking forward to seeing some new stuff on it! :)
There is a wiki at http://picobay.com/dtv_wiki/ but it doesn't contain much about hardware details.
There is some info at the DTV hacking forums and forum64.de.
I'm afraid it's not fully documented. There are effects left to discover. :)
You'll just have to find out how it works by experimenting.
EDIT: @scout: Fast reply! :) |
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Oswald
Registered: Apr 2002
Posts: 5094 |
I have one since it was sold in hungary, but somehow was even too lazy to make the most basic hacks so far :) |
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Shadow
Account closed
Registered: Apr 2002
Posts: 355 |
Great to see more people interested in the DTV. I just released my first (very simple) demo for it. I didn't even scratch the surface but I can tell the potential of that hardware is huge! |
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tlr
Registered: Sep 2003
Posts: 1790 |
Quote: I have one since it was sold in hungary, but somehow was even too lazy to make the most basic hacks so far :)
I guess you'll want keyboard + IEC at least. Those are very easy to add.
You probably want the color fix aswell which is a bit fiddly.
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Shadow
Account closed
Registered: Apr 2002
Posts: 355 |
Yeah, colorfix is a must. It's not easy to do, but without it the 256 color modes are almost worthless. |
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Oswald
Registered: Apr 2002
Posts: 5094 |
ok there's an awesome doc about the segment registers and virtual registers, (tho going into too much details at straightforward issues and skipping important ones) out there but I have a few questions.
what is the meaning at the SAC opcode of setting the virtual registers as source / destination ? LDA #$00 sets the destination virtual reg, and STA #$00 does write value of the source virtual reg?
how about the reserved registers? is it possible to use them or are they implementing internal registers such as program counter lo / hi, stack pointer, status reg ?
when it comes to segmenting there's one bit (most significant?) whose role is undescribed.
what does the 2 bit / segment do when I set it to rom/ram mode? does $01 does work the old way when it comes to ram/rom settings?
so much for now.
edit: wow this is wonderful, you can read at vich cpu cycle you are on a given line, and set the cycle where an irq is triggered :D |
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Scout
Registered: Dec 2002
Posts: 1570 |
Quote:what is the meaning at the SAC opcode of setting the virtual registers as source / destination ? LDA #$00 sets the destination virtual reg, and STA #$00 does write value of the source virtual reg?
I'm not sure what happens if you set SAC #$DE (source=$4000, destination=$8000) but doing a LDA *right* after a SAC actually performs the segment mapping.
LDA #$40
SAC #$DD ; Set accumulator mapping @ $4000
LDA #$04 ; Set highmem segment to $100000 (%xx0[b]00001 00[/b]000000 00000000)
LDA #$12
STA $4000 ; Writing in high memory now
SAC #$00 ; Accumulator is 'normal' again; filled with #$40
Tlr, Streetuff? Am I right about this? |
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Oswald
Registered: Apr 2002
Posts: 5094 |
scout, and what does SAC #$10 or SAC #$01 do ? you seem to be mixing things up as SAC itself does not change any segmenting itself only changing the ACC register mappings afaik. |
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Scout
Registered: Dec 2002
Posts: 1570 |
Quote:scout, and what does SAC #$10 or SAC #$01 do ?
I don't know. That is something I want to test myself too.
Keep you posted about that (or maybe the other dtv coders beat me to it ;)
Quote:
you seem to be mixing things up as SAC itself does not change any segmenting itself only changing the ACC register mappings afaik.
No, i am not mixing up things.
You must see the SAC and the following LDA as a pair.
First you set up the accumulator mapping (SAC) and after that the segment mapping using a LDA. |
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