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Everything posted by jum

  1. Good work! BTW what tools did you use to make the tunes?
  2. I've recently been modding a "Pixels Past" 32k 5200 cartridge PCB to be able to switch between 2 16k rom images in the 32k EPROM, using an external switch. This setup assumes that the 16k rom is mapped to 0x8000 in the 5200 memory space. However I noticed that many 16k roms seem to be mapped to 0x6000, and then the last 8k of the rom is repeated at 0xA000. (I also noticed this when writing the Jum52 5200 emulator) What I'm curious about is why this was done? Was it maybe some kind of anti-piracy mechanism, to make it harder to copy the cartridge?
  3. See attached picture (blue wire). Looks like resistor R41 (on my 2-port 5200, I think 4-port is the same). Like the other guys say, may be a good idea to add a resistor to the audio out (although mine sounds fine and the level seems OK).
  4. Should work with the 5200. Let us know how it goes.
  5. Here's a quick hand-drawn schematic. Not 100% sure about the polarity of the 0.1uF cap, or the connections to the 2N2222 / 2N3904 transistor (you should attach the transistor as per the schematic in your post). You could also try the schematic in your post. Will be interesting to see which gives a better picture. Disclaimer: I take no responsibility for any dead 5200's resulting from the use of this mod.
  6. Wow, this is super impressive! Screenshot from Jum52 emulator:
  7. Yeah, pretty unusual fault. Lots of pondering over schematics and datasheets, and probing with an oscilloscope, was involved... Have now discovered the GTIA may be faulty - the player to player collisions don't seem to work! (Also unusual).
  8. Final install of the composite mod, with screenshots from a small LCD monitor:
  9. Finally some closure to this forum post Fixed my 5200 after 14 years - turns out it was a faulty inductor L3, which is on the SELECT line for the 74LS245s that multiple the address going into the RAM.
  10. Here are the pictures, although in person the images on the screen is not so bright and the ghosting is much less noticeable. Hopefully putting the mod onto a proto board and a bit of tweaking will give a slightly better image. Note: - RF modulator removed completely - Resistor R33 leg (audio) lifted off the board - Video signal taken from left side of L12 (green clip) - +5V taken from top of L13 (red clip) - Ground taken from top side of C40 - Transistor used in mod circuit is KSP2222N (2N2222?) - Resistor used in mod circuit is 100 Ohms These are just the first points I saw on the schematics that looked like they have the right signals, possibly there are better points to take the signal off.
  11. Just removed the RF modulator from my 2-port 5200 and wired in a simple composite connection using 1 transistor (2N2222?) and one resistor between video out and ground. Also cut the one leg of the resistor (R33?) that connects the audio to the video output. Have yet to connect the audio output. Very surprised at how good it looks (way better than 2600 and 7800 composite mods I have done). Will post pictures later. Tweaked the big pot on the lower right side of the board to get the colours correct. Video output may be a bit "hot", need to check that and maybe add voltage divider to the circuit.
  12. I was just testing an NTSC ANTIC in my PAL 800XL - It stretches the screen vertically compared to the PAL ANTIC.
  13. Fantastic project, great work Thomas. I am definately going to try build one of these (for PAL my 600XL and 800XL). Would love to contribute code / testing / 3D case designs etc, but will probably not get the time (too many other projects that I am obliged to finish first).
  14. Should this "fix" not be add to the standard cc65 repository: https://github.com/cc65/cc65/blob/master/libsrc/lynx/bootldr.s ??? (Just asking because this is the version of cc65 that I use).
  15. jum


    Yes, that is true for this specific example, but only because you have optimised it, not the compiler. It's not a good example, maybe a better example is something like: for (i = 0; i < 32; i++) { B[i] = A[i] * 2 + 1; // some processing is happening, not just a memcpy } As said before, the point of the comparison is to see how the the 2 compilers handle the same code construct.
  16. jum


    OK here's the cc65 code and ASM output for comparison. Note I used the cc65 "-Or" optimisation flag to enable register variables: cc65 code: void main() { uchar i; asm("nop"); i = 31; do { MIKEY.palette[i] = work_palette[i]; i -= 1; } while ( i >= 0 ); asm("nop"); for (i = 0; i < 32; i++) MIKEY.palette[i] = work_palette[i]; asm("nop"); } Assembler output (.s file): ; --------------------------------------------------------------- ; void __near__ main (void) ; --------------------------------------------------------------- .segment "CODE" .proc _main: near .segment "CODE" jsr decsp1 nop lda #$1F L0060: sta (sp) ldx #$FD lda #$A0 clc adc (sp) bcc L0044 inx L0044: jsr pushax ldy #$02 lda (sp),y tay lda _work_palette,y ldy #$00 jsr staspidx lda (sp) sec sbc #$01 bra L0060 L005F: lda (sp) cmp #$20 bcs L004E ldx #$FD lda #$A0 clc adc (sp) bcc L0058 inx L0058: jsr pushax ldy #$02 lda (sp),y tay lda _work_palette,y ldy #$00 jsr staspidx lda (sp) ina sta (sp) bra L005F L004E: nop jmp incsp1 .endproc Way longer/slower (for this example), and very hard to follow!
  17. jum


    Love that 8bitworkshop web IDE ( https://8bitworkshop.com/v3.4.2/? )
  18. jum


    Would be nice to see a comparison with cc65 generated ASM. If I get a chance tonight I will do same code in cc65 and upload the asm generated. Also would need to expand the lynx lib/module for Millfork.
  19. Wouldn't mind getting a box for my MegaPak cartridge.
  20. Has anyone tried using Millfork language to compile something for the Lynx? A "middle-level programming language targeting 6502-based, 8080-based and Z80-based microcomputers." https://github.com/KarolS/millfork Readme says that it can target Atari Lynx and Atari 8-bit. (although primarily for C64).
  21. I admit I first thought the concept was a bit simple/stupid. But the game is great! The added challenge curve through the levels is perfect, the gameplay is also perfect for a handheld. Somehow it reminds me of Klax (different challenges that get harder as you progress).
  22. Cool game! It kind of sucks you in and keeps you interested. Very playable/fun. Nice gfx and music. Got stuck after a while, but definately going to play the final version. Like someone else above, I also noticed the (lack of) jump physics/curve, and the music can get repetitive after a while.
  23. Very impressive looking version of 3D Tic Tac Toe. Also cool chiptune style music On my Lynx II (original screen) the gfx look a little tiny, very difficult for me to read the text. Maybe the grids should take up more space on the screen. (Also note my eyes are not good).
  24. Fun game! Great gfx, sound and gameplay. Never played it on Atari 8-bit before. I think it's the sort of game that fits the Lynx perfectly. Played on Lynx II via RetroHQ SD cart.
  25. Well I did finally manage to get the game running on my Lynx II with RetroHQ SD card. I blame TGI for messing up my fancy "dual layer SCB" system Game is very fast on the real Lynx (and a bit blurry!), but very slow in Handy... Here is the latest version: Sky Raider 20190906.zip
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