BLITTER RE-CREATION THOUGHTS

[Badwolf]

I can't think of anything intelligent to say but this is an awesome achievement.

Congratulations

AOL!

BW

[mrbombermillzy]

Good progress so far.

Hopefully this is still being worked on?

Ive been knee deep in blitter code optimising (for game use both on the ST and the C64DTV), so with a clearer view of what would help create a better blitter than before (and seeing how the DTV blitter has been improved substantially over the ST/Amiga versions), I was throwing some info out there, just so its noted and if at some point you wish to add any extra features:

1. 'Copy if ! = ' logical operator:

For typical game use with 'sprites'/BOBs over a background image, this would save ~33% of blitter use (certainly for packed pixel operations anyway). So instead of 3 blits to the same location (background restore/mask/image), it would be reduced to 2 (background restore/image).

2. Source/Destination step rate:

Step rate being how many pixels are 'stepped' (think TT shifter smear mode) per S/D linear increment iteration. So e.g. a source step =1 and destination step =2 would create a destination image block of 200% size. Alternatively, a source step =2 and a destination step =1 would reduce the destination image to half size (possibly useful for some form of sample playback filtering too?) Step rates can possibly have decimal point position at say bit 4 for e.g. sub pixel/smooth zoom effects, etc, but at the cost of the zoom/reduce size extremes.

3. Extra logic input comparator operations:

Adding an extra input source would give more scope for source combining operators to allow for such things as low latency alpha blending/additive alpha effects, or other stuff I havent thought of yet.

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Im sorry if you think I may be 'jumping the gun' a bit and I understand it is very likely to be too early to be thinking about any of this, but I just wanted to make a permanent note somewhere while I was 'in the zone' otherwise I may well forget it all or suffer loss of focus (blame the kids!) when someone asks me for my thoughts. (Im thinking of what happened in a conversation with @Badwolf at one of the earlier CL events!)

Anyway, perhaps have a look at the C64DTV blitter documentation for more 'creative insights':

https://www.c64-wiki.com/wiki/C64DTV_Pr ... _REGISTERS

[exxos]

@Icky looking back here viewtopic.php?t=4585

There is V4.1

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I have PCB for V4.0 and schematic for 4.1. So not sure if my files got corrupted at some point.

I don't remember if I was doing fixes to it or something over the V4.0 now.

But IIRC it was chip shortages causing all the delays.

Though I thought the MAX10 series could do 5V inputs ? So not sure why we have IO buffers ? Or was it some other chip which could do 5V ? Really can't remember now

The BGA chip was a problem, but the UK PCB guy I am using is still talking to me after some months, so I could ask him about BGA stuff..

[exxos]

@ijor It looks like the 10M02SCU169A7G was used for the blitter. Do you know how much space is left in that device ? Using the 02 will make buying the chips a lot cheaper than going for the 04.

[ijor]

Though I thought the MAX10 series could do 5V inputs ?

No, it is not 5V tolerant.

It looks like the 10M02SCU169A7G was used for the blitter. Do you know how much space is left in that device ? Using the 02 will make buying the chips a lot cheaper than going for the 04.

I don't remember, but I will check and let you know later.

But the devices are pin compatible. Altera supports something that they call Vertical Migration. You can use the same board for either the 02, 04, or even larger devices. Conceivable, larger devices could have optional extra features that don't fit in the basic (02) version.

[alexh]

Is the BLITTER a PLCC chip? There has been some what looks like great "open source" work done in the Amiga world at making FPGA boards that plug into empty PLCC sockets. I can share the links if relevant.

[exxos]

Is the BLITTER a PLCC chip? There has been some what looks like great "open source" work done in the Amiga world at making FPGA boards that plug into empty PLCC sockets. I can share the links if relevant.

Worth a look either way

[exxos]

But the devices are pin compatible. Altera supports something that they call Vertical Migration. You can use the same board for either the 02, 04, or even larger devices. Conceivable, larger devices could have optional extra features that don't fit in the basic (02) version.

Good to know thanks.

[Icky]

Ooo I am back.

Though I thought the MAX10 series could do 5V inputs ?

No, it is not 5V tolerant.

Correct and hence the board has 5V <-> 3V3 IO

It looks like the 10M02SCU169A7G was used for the blitter. Do you know how much space is left in that device ? Using the 02 will make buying the chips a lot cheaper than going for the 04.

I don't remember, but I will check and let you know later.

But the devices are pin compatible. Altera supports something that they call Vertical Migration. You can use the same board for either the 02, 04, or even larger devices. Conceivable, larger devices could have optional extra features that don't fit in the basic (02) version.

We used the 02 on the original board we got working and I believe it had a little space left not much.

One thing I have noticed about the Max10 Vertical Migration it doesn't go from 02 to the others well. 04 upwards migrate well. That said a small tweak of the board will be easy.

Is the BLITTER a PLCC chip? There has been some what looks like great "open source" work done in the Amiga world at making FPGA boards that plug into empty PLCC sockets. I can share the links if relevant.

I had been playing with a PLCC version of the board but that could work. The board pictured was for H5 so we could develop and then eventually end up with a PLCC plug-in board.

I'll come back here shortly once I sort out where I got to with this design.

[Icky]

Ah now it has come back to me after looking at my files. I was last working on a PLCC version and also a board that could be configured as BLITTER, GLUE or MMU.

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