Jump to content

Search the Community

Showing results for tags 'pokey'.

More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


  • Atari Systems
    • Atari 2600
    • Atari 5200
    • Atari 7800
    • Atari Lynx
    • Atari Jaguar
    • Dedicated Systems
    • Atari 8-Bit Computers
    • Atari ST/TT/Falcon Computers
  • Gaming General
  • Marketplace
  • Community
  • Game Programming
  • Site
  • Classic Gaming News
  • The Club of Clubs's Discussion
  • I Hate Sauron's Topics
  • 1088 XEL/XLD Owners and Builders's Topics
  • Atari BBS Gurus's Community Chat
  • Atari BBS Gurus's BBS Callers
  • Atari BBS Gurus's BBS SysOps
  • Atari BBS Gurus's Resources
  • Atari Lynx Programmer Club's CC65
  • Atari Lynx Programmer Club's ASM
  • Atari Lynx Programmer Club's Lynx Programming
  • Atari Lynx Programmer Club's Music/Sound
  • Atari Lynx Programmer Club's Graphics
  • The Official AtariAge Shitpost Club's Shitty meme repository
  • The Official AtariAge Shitpost Club's Read this before you enter too deep
  • Arcade Gaming's Discussion
  • Tesla's Vehicles
  • Tesla's Solar
  • Tesla's PowerWall
  • Tesla's General
  • Harmony/Melody's CDFJ
  • Harmony/Melody's DPC+
  • Harmony/Melody's BUS
  • Harmony/Melody's General
  • ZeroPage Homebrew's Discussion
  • Furry Club's Chat/RP
  • PSPMinis.com's General PSP Minis Discussion and Questions
  • PSPMinis.com's Reviews
  • Atari Lynx 30th Birthday's 30th Birthday Programming Competition Games
  • 3D Printing Club's Chat
  • Drivers' Club's Members' Vehicles
  • Drivers' Club's Drives & Events
  • Drivers' Club's Wrenching
  • Drivers' Club's Found in the Wild
  • Drivers' Club's General Discussion
  • Dirtarians's General Discussion
  • Dirtarians's Members' Rigs
  • Dirtarians's Trail Runs & Reports
  • Dirtarians's Wrenching
  • The Green Herb's Discussions
  • Robin Gravel's new blog's My blog
  • Atari Video Club's Harmony Games
  • Atari Video Club's The Atari Gamer
  • Atari Video Club's Video Game Summit
  • Atari Video Club's Discsuuions
  • Star Wars - The Original Trilogy's Star Wars Talk
  • DMGD Club's Incoming!
  • DASM's General
  • AtariVox's Topics
  • Gran Turismo's Gran Turismo
  • Gran Turismo's Misc.
  • Gran Turismo's Announcements
  • The Food Club's Food
  • The Food Club's Drinks
  • The Food Club's Read me first!
  • The (Not So) Official Arcade Archives Club's Rules (READ FIRST)
  • The (Not So) Official Arcade Archives Club's Feedback
  • The (Not So) Official Arcade Archives Club's Rumor Mill
  • The (Not So) Official Arcade Archives Club's Coming Soon
  • The (Not So) Official Arcade Archives Club's General Talk
  • The (Not So) Official Arcade Archives Club's High Score Arena
  • Adelaide South Australia Atari Chat's General Chat & Welcome
  • Adelaide South Australia Atari Chat's Meets
  • Adelaide South Australia Atari Chat's Trades & Swaps
  • KC-ACE Reboot's KC-ACE Reboot Forum
  • The Official Lost Gaming Club's Lost Gaming
  • The Official Lost Gaming Club's Undumped Games
  • The Official Lost Gaming Club's Tip Of My Tounge
  • The Official Lost Gaming Club's Lost Gaming Vault
  • The Official Lost Gaming Club's Club Info
  • GIMP Users's Discussion


There are no results to display.

There are no results to display.


  • AtariAge Calendar
  • The Club of Clubs's Events
  • Atari BBS Gurus's Calendar
  • ZeroPage Homebrew's Schedule

Find results in...

Find results that contain...

Date Created

  • Start


Last Updated

  • Start


Filter by number of...


  • Start










Custom Status



Currently Playing

Playing Next

Found 31 results

  1. Hi everyone, I'm a complete n00b and I'm looking for some advice. I've dusted off my old 600xl which was a hand-me-down from my uncle back in the late 80s and decided that it would be a great project to get it back working again. Upgrade it and show it to my uncle, who's now in his 60s. its a stock 600xl, PAL region, membrane (mylar I think) keyboard. I've created a twitter thread here documenting my progress to date: So far I've given things a general clean and retro-brightened the case and that of the 1010 cassette deck. I've checked the PSUs, 600xl is fine but the tape drive doesn't work. I've sourced one that will do the tape drive from my parts bin. Everything went back together fine, hooked it up to the TV, turned it on and very surprisingly got the "ready" prompt. Unfortunately the keyboard isn't working with the exception of reset, option, select, start, and break. Thinking it was membrane oxidation, I stripped the keyboard back down and used a magic sponge to clean all the traces. I was surprised at how well that worked! I also swapped around the 2x 4051 chips and reseated C012294-19 (POKEY, I think) to see if that would make a difference. Unfortunately not, same as before only the silver buttons & break work. Those keys were enough to get into the diagnostics; memory checked out ok but no sound over the antenna cable. So I'm looking for a bit of guidance on where to go next. Pokey dead? I can imagine they're hard to come by these days. Some googling lead me to something called POKEYMAX. Keeping in mind that I'd like to upgrade the memory too, what options do I have? Advice and guidance welcomed! Thanks T
  2. Warning: severe music geekiness ahead. I’ve been looking at Synthpopalooza’s POKEY tables, and thinking about what he wrote in the Popeye thread (in 16+8+8 mode using the 16-bit channel for bass, which makes sense after being initially counterintuitive to me) and how some POKEY games don’t sound as good as I think they should. I wanted to look at the errors of various frequencies, meaning the difference between what POKEY produces and what that note ideally should be. The easiest way for me to do that was to roll my own note table. Here’s what I initially noticed: No surprise in 16-bit mode: errors are very small throughout the range. 64 kHz clock has a good range of about an octave and a major third. 15 kHz clock has a slightly wider good range, but there are some sketchy combinations (example: E1+B1 and especially E1+E2). I was hoping to find some cases where using an off-table value would be more correct in certain circumstances. There are a few (examples: with 64 kHz clock D3+B3 chord would be more consonant using $D8 for the D, and with 15 kHz clock some keys would work better using $BD for E1) but not many immediately apparent. My initial plan had been to make tables in different temperaments, but at this point I started wondering: what if we had different pitch tables for different keys? That would let us approximate just intervals. Unlike a piano, a 7800 program can easily change tunings on the fly. And what if we switch the tuning basis from A4=440 to whatever nearby number happens to work well for POKEY 8-bit in that key? A=440 Hz is not a law of nature. The Berlin Philharmonic used to tune to A=448, and I know of commercial recordings done as low as A=392. I started working on B major since 64 kHz clock’s lowest possible note (AUDF=$FF) is a B. Tuning to that (which gives A=449.44) produces numbers that look pretty decent with either clock. The D#2 to E2 interval is not ideal, but in real music it may not be noticeable. If it is, tweaking the E2 value might help. I moved to C major. After a little experimenting, I found something very interesting: with A4=436.11, and D=C*10/9 (a slightly different form of just intonation, hear samples here), the 15 kHz clock gives near-perfection from C1 all the way up to C5. The only bad note is F4. Every other note is right on target. Note that this not only goes much lower than the equal temperament chart with 64 kHz clock, it also provides several more in-tune notes on the high side. That C modulates well to G major, with a similar range. The Ds and F#s get farther off than I’d like but can be tweaked to at least match each other. The other notes in the G scale are correct. When 8-bit bass is unneeded, a higher tuning (A4=443.90) with 64 kHz clock produces a perfect C scale from C3 all the way up to C7 except for F6. Just to be clear: when I say tune to some number, I’m just talking about how I determine the AUDF values for the tables. The tuning itself is not a setting. It’s all theoretical right now, but I hope to put it to use soon. How? Well, the low C scale looks good enough that it could work with 4 channels as-is, avoiding that F4. The G and B scales could also be used that way, but might be better suited to 16+8+8 mode, but instead of using 16 for some specific line, use it for whichever note needs it at the moment. It also might make sense to compose for 4 voices, but drop one voice when another needs 16 bits. Or, could use Synthpopalooza’s preferred 16 (for bass)+8+8 configuration, but with the high-range C tuning. Compared to conventional tuning this provides two extra octaves up top, and tighter intonation to boot. If this works out I will expand it to other keys and other distortion settings. link: Yet Another POKEY Table Explanations of colors are at the bottom of the 64 kHz columns. The light-colored text can be difficult to read, which is somewhat intentional, considering the meanings of the colors. Use the bottom tabs to switch keys or to conventional equal temperament.
  3. Some time ago I finished working on a document where I describe results of my research on the POKEY's C distortion. It says about the rules related to generating the distortion as well as about the ways to stabilize bass sounds referred to as C bass (or "Donkey Kong" bass by Synthpopalooza). The instability issue has been already mentioned in the threads: http://atariage.com/forums/topic/116835-polycounter-reset-on-pokey http://atariage.com/forums/topic/212280-pokey-question-distortion-12-donkey-kong-bass Beside the document there is an excel file attached, which is a supplement for the study and contains POKEY frequency/note tables for all its clocks. There are also slides which I was presenting on WAPNIAK party in 2017 and a Bass Tester program which allows you to play a bit with the C distortion in practice. The program is compiled in three versions differing in the method of counter synchronization - two variants of first method and the second metod. The Bass Tester is provided together with its complete source code. On screen you will see what keys can be used for various settings. The manual is actually included in the slides. If used under the Altirra emulator, it's worth turning on the Audio Monitor to watch oscillograms. What is not mentioned in the manual is key 0 which toggles accurate phase modulation. I hope you will find it all useful. c-distortion.zip
  4. How many mods has someone actually squeezed into a 600XL? I love the small size, but realistically I know there is limited real estate inside. It would be great to have everything: U1MB, VBXE, stereo pokey board, u-switch, TK-II or AKI, Rapidus, and I'd have to do the 64k and a/v mods. Is it doable or do I need to play it safe with a larger model?
  5. Hi All, Seriously, I have no idea what is happening here. I am working on a TURBO BASIC program that will let the user exercise their (relative) ear. It is planned to test intervals melodic and harmonic and probably a few other things. To come as close as possible to the wanted frequency (I have really a sensitive and precise ear) I use 16-bit pokey registers in stead of 8bit. Downside is that I only can play 2 tones together, but ok... Perhaps I might decide later to go to the 8bit 4# voice capabilities of pokey. Earlier today I found that DSOUND 0,4020,10,10 would produce a perfect 220Hz A and and DSOUND 0,2008,10,10 would produce a perfect 440Hz A. I was very happy with the results, I saved my program to disk and that was that. Now I fired up the Atari with Turbo Basic and I was playing again with the DSOUND command and I was not as satisfied as I was earlier today. I was like: hmm it is not right. So I started playing again with it and I found different values. After checking: DSOUND 0,4028,10,10 gives the perfect 220Hz A DSOUND 0,2017,10,10 gives the perfect 440Hz A DSOUND 0,1001,10,10 gives the perfect 880Hz A Ok it is not really a big difference, but still, I was not as close as I would have thought. So my 2 questions are: How stable is this anyway? Can I assume that pokey in 16bit modus produces a steady frequency or does it fluctuate (when colder/warmer) or is it a different part on the PCB that might have influence on the frequency? (Like the audio-out circuit)? I am using the speaker of my television set, so it is not directly what comes out of pokey. In the Turbo Basic Manual by Wil Braakman I read a formula: "de berekende frequentie in HERZ nu 1789790 / (2*freq+14) bedraagt. De frequentie bedraagt dan 16 bit (0 . . . . 65535)" (Braakman, 1988, p. 3-36). This means that the 16bit pokey value for 440Hz would be: 1789790 / (2*440+14) is approx. 2002 which is closer to my earlier find of 2008, and than my newer find of 2017. It seems that either this formula is wrong, or my ears/tuner-app. My personal findings using ear and tuner-app come way more close to 220Hz, 440Hz and 880hz than this formula. Is there a better formula somewhere? Or is there something else wrong? Or do I ask too much of a formula anyway? I am really interested in this stuff, I hope someone can help. Marius -- Braakman, W. (1988). TURBO BASIC XL 1.5 MANUAL. 's-Hertogenbosch, Netherlands: Stichting Atari Gebruikers.
  6. Both with and without GUI available here in 32 and 64-bit flavors: http://messui.the-chronicles.org/ Necessary BIOS files - leaved zipped - do not unzip - and create a ROMS folder in the root MESS folder (I.E. C:\MESS\ROMS): NTSC: a7800.zip PAL: a7800p.zip For those interested in utilizing all the fancy HLSL video options you need these files: hlsl.zip The hlsl.zip file you need to unzip and place the folder in the MESS root folder (I.E. C:\MESS\HLSL) Here are some additional support folders - to be handled similarly to the HLSL folder: Artwork (Provides additional screen/monitor effects and overlays): artwork.zip [C:\MESS\ARTWORK] Controller Mappings (X-Arcade, HotRodSE, etc.): ctrlr.zip [C:\MESS\CTRL] Emulator Documents (Command line options, explanation of settings, etc.): docs.zip [C:\MESS\DOCS] Donkey Kong XM and Bentley Bear - Crystal Quest are now playable with full POKEY support. Of course Commando, Ballblazer, Beef Drop, Froggie, Pac-Man Collection XM/POKEY edition still work beautifully as well. Any game images you have can be zipped or unzipped, but must have a header (*.a78 files) and placed in a folder called software (I.E. C:\MESS\SOFTWARE). Of course, you may place you game images anywhere, but need to configure MESS accordingly.
  7. I have an Atari 800 that I'm using for parts because it has no sound and acted as though the space bar was always pressed down. I needed a POKEY for my Cuttle Cart 2, so I harvested the one from the 800. The CC2 wouldn't work after I installed the POKEY but worked fine after I removed it. I went to Wikipedia and read that the POKEY is also responsible for scanning the keyboard. Is it possible that the bad POKEY was causing the space bar issue? I read elsewhere that many 800s had bad space bars because Defender players used it so ofter for hyperspace. Thanks for any advice.
  8. So I pulled my 800XL and gear from storage. It'll boot up to READY prompt, play a cartridge game, and pass all self tests. However, I'm unable to use any of my peripherals (2x 810 drives - one Happy, 1010 recorder, and 1025 printer). Any help isolating the problem is greatly appreciated. Here's what I've tried so far... - CSAVE: No apparent issues trying to save "hello world" program to cassette. Beeps and starts spinning while recording. Back to READY prompt and recorder stops when done. - CLOAD: Error 138. Apparently didn't record. RETURN key properly starts recorder playing but no noises. - LIST/LOAD D1 & D2: Error 130. Nothing. Neither drive will spin when turning computer on. OPTION-on goes straight to test screen. Drive switches are set to 1 & 2, and have tried swapping them, plus each individually as D1. Note: Drives will power up with momentary busy light when computer is off. - LIST "P:": Error 138. Nothing. Printer head resets position when turning on computer. I've tried all peripherals daisy chained and individually, swapping out the IO cables with same results. I removed all socket chips from the motherboard, cleaned everything and no difference. Need a new POKEY chip? Anything else it could be? Thanks for the help guys!
  9. Hey, I've released a new music album that contains 11 tracks written between 2010-2015 for Atari pokey sound chip (found in 8-bit Atari computers) with Raster Music Tracker. I thought this might interest a few folks here. Check it out: https://warlord.bandcamp.com/album/pokey-nights
  10. I've tried to get a sort of PWM sound in a tracker. And I don't mean an accidental effect, but something more or less stable and predictable. The idea is a development of Raster's idea from his 'Delta' cover and 'C64 synth' instrument. Here is a mediocre example, but I hope you can hear and see what is going on the first channel. XEX included as well. KORTO.xex
  11. Hi Guys! Does anyone know where I can buy a Harmony-like or Everdrive-like SD Cartridge for the Atari 7800 with a Pokey chip or who can make one if I sent them a Pokey chip? Thanks! My email is [email protected]
  12. Recently I have been "collecting" all the different ways to generate pulse, sawtooth and triangle waves with the pokey chip, and while doing that, I thought of a new way to approximate a sawtooth wave. Well, I think it's a new way because I did not read about it somewhere else, but I'm not sure. It works like this: play frequency divider F on channel a, distortion 10 play frequency divider F/2 on channel b, distortion 10, half volume F/2 must be an integer, so F&1 == 0 (i.e. only even numbers for F) AUDFx are loaded with F-1 and (F/2)-1 after setting AUDFx's, restart the polycounters by writing to STIMER This results is one channel playing exactly double the frequency of the other and both are almost exactly in-phase. The result is as follows: a: 001100110011 b: 010101010101 r: 012301230123 To the ear, this sounds a lot like a sawtooth wave. Basically, both waves add up if they're in sync. There is no decrease in volume as is the case with interfering 1.79MHz based waves resulting in a sawtooth.
  13. I'm unable to find the answers to these two items, probably due to some failure on my part. I've found mention of these mods, or occasionally a link to a dead external site, but I haven't found the step-by-step handholding that I need to get them done. I've recently composite modded my 7800. I notice that the Pokey audio level is significantly lower than non-Pokey. I'm pulling Pokey from the top pin of C10, next to the channel select switch, and it's wired it directly to my audio output jacks. What do I need to do to fix my audio level issues? I also have a 7800 that is not compatible with Supercharger (it seems to go into a reset loop). I've heard mention of a simple mod to fix this, but could not find it. How is this done, and could I get a link to it? Are there any down sides to this modification?
  14. Greetings, I've just been trying to load this program on my 800XL from a disk image available here: http://jaskier.atari8.info/# - It's TMC2.atr It loads for a minute and then displays a DOS-looking prompt. I'm new to Atari 8-bit comps, so I don't know what the problem is. I thought with these machines the prog would load automatically when the machine powers on. Does the same in an emulator, and I have a disk full of games that loads just fine. The amount of time I've spent on this is starting to get ridiculous, so I'm hoping someone can just tell me in 5 seconds what it is I need to do Thanks!
  15. I recently picked up a 5200 4-port. It's missing several case screws. Can anyone confirm the correct screws used for the case? I think the screws that came with this 5200 are type b #6-20 3/4 sheet metal screws. Is that what it should be or perhaps these were used to replace the original screws that were of a different type? Here's what was in my 5200: It didn't have a power supply, but I found one elsewhere. It's an 11.5v version. I tested it with a multimeter and it's outputting 14.5 volts. From what I've found the voltage regulators in both the case and the switchbox should be capable of handling over 30 volts. Do I have any reason to worry about using the power supply? 3 volts over seems like a big difference, is that typical or should I start looking for another power supply? The traces (or is it the soldermask) on the back side of the board on is wrinkly (see the POKEY to C104 wire image below). Is that normal or is it a sign of something I need to be worried about? It looks like the VCS adapter compatibility mod was applied to this board, but I also see a capacitor between pins 1 and 17 on the POKEY and a wire on the underside between pin 1 of the POKEY and C104. Is this a known mod? Any idea what it's for? Trying to smooth out power to the POKEY perhaps? In the middle of the rat's nest that is the VCS mod, I see a resistor and a capacitor (?) wired in parallel from between the two resistors connecting R11 and C10 as part of the VCS mod. There's also a diode wired to either side of R10. Any idea what they're for? The parts side of the pcb, marked CA018087, has no revision. The solder side, marked C018085 is rev 7. I will probably apply the mod to separate the power from the RF. I was also thinking about doing the mod for composite and/or s-video, but doing that would make the VCS mod pointless, right? If I did the composite/s-video mod I could pull the VCS mod out. If I did that would I need to reconnect pin 24 on the cartridge slot to ground? Thanks for any help/information you can provide. I hope to get this 5200 up and running soon.
  16. Hi all, I've been browsing the Atariage forums for a long time now and with help from a lot of great posts I've modded and resurrected quite a few Atari systems. Thank you, to all of the knowledgeable and friendly people who post here. I finally came up against some issues that I haven't been able to sort out by searching the forums. I'll start out by telling everybody about the system I have. It is a 4 port 5200, (the non VCS adapter compatible one). I bought it untested from ebay with 3 games and 4 controllers, but no power supply or switchbox. I bought an original 4 port power supply and did the power mod to eliminate the need for the all in one switchbox, (thank you Mitch and CPUWIZ). I am using the original soldered on RF cable to connect the 5200 to my TV, (I'll likely do the video mod after I sort out the issues I'm having). I've cleaned up 2 of the controllers and the buttons are working good. The joysticks were too, but that's changed. Anyhow after I completed the power mod and hooked the 5200 to my TV it looked and sounded great, no problems with any of the games I tried. However some of the controller inputs weren't reading, but the system seemed to be working great otherwise. After a while thought a new problem started. The system would not turn off with the power button and I started getting graphical errors with lockups. The power is on as soon as I plug it in, without even pressing the power button. After reading a few posts here it seemed that I my power problem and graphics troubles were likely due to a bad 4013 flip flop. I bought a pack of 25 and have tried about half of them - no change, the problems remain. As a matter of fact even without a 4013 socketed the 5200 powers on as soon as I plug it in and will on turn off. I also still get graphical corruption and lockups after a short time too. Aside from changing out the 4013 I've also tested the power switch for continuity. It has continuity when the button is pushed and none when it isn't, so the button isn't the problem. This has me really stumped, any suggestions would be greatly appreciated. On to problem 2 - the controller input issue. As mentioned I've cleaned and got working 2 of the controllers. So after some searching of the posts it seemed likely that my problem was due to faulty CD4052 ICs. I bought a pack of 25 and replaced the 5 that are on the board. Success! All of the buttons now work as they should. However I am having trouble with the joysticks. The joysticks worked fine initially, before I changed the CD4052s, but started to give me trouble before I did the swap and it didn't go away with the swap. As soon as I start any game it acts like the joystick is being pushed all the way down and to the right. This happens even if the joystick is centered and does not change even if I move the stick all the way up and to the left, or any other direction for that matter. It's the same with both controllers and the same with both ports 1 and 2, I have not tried ports 3 or 4. More reading on the forums is leading me to suspect I've got a fault Pokey chip. The Pokey looks slightly discolored around the edges. I don't have another to swap out, yet, but that is what I plan on trying next. I've also cleaned the pins in all 4 or the ports. Again any suggestions would be greatly appreciated. I do own a multi-meter and a decent soldering iron, (which I am pretty good at using). I also got really lucky with the board revision in my 5200, every IC on the board is socketed, so no de-soldering required to swap out chips. This is the first 5200 I've owned and I've got a lot of great games that I want to start playing. I know some of you guys have seen it all with these systems, so I'm hopeful that I'll be able to sort it out with your help. Thanks in advance.
  17. Hi everyone, I just want to share some tunes I made using 15 kHz clocked Pokey in basic version of Raster Music Tracker (1.28). I believe they sound a bit different than tunes made with a regular clock (64 kHz). So check please if you wish and enjoy! I think they sound best when listened to on a real hardware, therefore I made recordings also and put on my bandcamp profile. So if someone doesn't use a real piece of hardware, please follow the links: http://makarybrauner.bandcamp.com/track/echoes http://makarybrauner.bandcamp.com/track/step-it-up EchoesMB.xex StepItUpMB.xex
  18. Title pretty much says it all. I need a POKEY for a 5200 but have no soldering skills. Ballblazer is cheaper than Commando, so I thought I'd go that route. Thanks!
  19. The loud "SQUAWK" made by the Asm-Ed cartridge, and Cntl-2, and some other software has always been very irritating to me. Does anyone know how to calm it down (short of muting the sound on the speaker)? Thanks, Larry
  20. I've been meaning to start a topic about my abbuc hardware competition entry, a replacement for the Pokey chip. It's been mentioned in a couple of threads but I thought many people may have overlooked it. I tried to be sensitive to cost in my design, though once the full details are released (after competition result) it will be fun here to brainstorm ideas to make it even cheaper! Clearly there are still plenty of real pokey chips, however the supply is starting to become more limited and prices are on the increase. --- PokeyMAX Introduction The PokeyMAX is a complete replacement for the Pokey chip. It is derived from the work on the EclaireXL project, a complete FPGA based Atari 800XL clone. The intention is to build replacements for all of the Atari custom chips using this technology and Pokey has been built first. It can be used either to replace a broken/missing pokey, as a stereo upgrade, or just for fun! Features If pokey is socketed, zero wire installation (mono) Dual pokey mode Pins for 3 audio outputs (left channel/right channel/mixed) Small footprint, only a few mm larger than original IC Supports all features: 8x paddle inputs, IRQ, serial I/O, audio output, two tone mode, high pass filter and keyboard scan High level of compatibility Digital logic The PokeyMAX is built around the Altera MAX10 FPGA. This was chosen due to its integrated flash memory, power conversion, small size and low cost. The contained logic itself is described in VHDL and Verilog and then synthesized using the Quartus II software. Level conversion Most modern FPGAs no longer support 5V logic. While it is possible to find a few they are a vanishing breed. The MAX10 only supports up to 3.3V logic, so an IDT quickswitch level converter IC is used to connect to the high speed lines (A/D/IRQ/serial io etc) safely. Chip select Unfortunately I needed more level conversion lines than provided. TI came to the rescue with some 5V tolerant multi-function logic chips with which I was able to combined CS/!CS into one. Power The MAX10 requires a single 3.3V power supply, it then internally generates the rest of its supplies. This is very convenient, since often FPGAs require 3 or more different voltage levels. There is a switch mode regulator (LM3670) to convert from 5V to 3.3v in an efficient fashion. Paddles These are handled by charging a capacitor that we then check the level of using an LMV339. This is similar to the well-known LM339 comparator, except much smaller! The comparator is used since the level can be set very precisely rather than relying on when the FPGA detects a logic high. The level itself is set to 2.2v using the voltage divider on the right. It is also convenient since its open drain output means there are no level conversion issues. For the drain transistors, a 5V tolerant IO extender chip is used. The FPGA communicates with this over an I2C bus. Keyboard scan An IO extender chip drives the 6 keyboard lines and then reads the response. This is convenient since it only requires an I2C bus to the FPGA and the IC is much smaller than the level converters. JTAG The core may be upgraded or debugged using an Altera USB blaster connected here. Several of the JTAG pins are dual use and can be used as general IO. So we could for instance in future plug in i2c devices here or use for A5 (with external level converter) to allow quad pokey or sid etc. Audio filter The audio output uses a delta sigma dac. An RC circuit is used as a simple audio filter to smooth the output from this. There are four audio outputs, which are currently fed to pin 37 and 3 header pins (left/right and mixed). Note that the next stage much not draw a lot of current from the rc filter or it will cause distortion. A4 Pokey has 4 address pins (A0-A3). To make space for a 2nd pokey another address line is needed. For stereo connect to A4. Errata: Note that the "paddle capacitors" should not be populated and RA1 should be 0 ohm since these are already on the main board, this was a schematic error.
  21. https://www.youtube.com/watch?v=C-mntFO3gPg This was fun to do.
  22. Thanks to the efforts of foft (Mark Watson) and his Atari FPGA project, there is an open source FPGA pokey implementation available. As a little Easter bank holiday project, I thought I'd have a go at using it to make a dual pokey cartridge using a prototype of the Ultimate Cart as the starting point... Two of the fpga pins act as audio left and right, and I've hooked them up to a low pass filter on some perfboard, along with a 3.5mm stereo jack (which leads to my TV's audio input). It was pretty easy to make a firmware for the Ultimate Cart that included two of foft's pokeys, his DAC and a bit of VHDL to hook them up to the cartridge port. Then I modified TMC and RMTPlayer (with a hex editor) to output to the two pokeys at $D50x and $D58x. I guess technically this atari has 3 pokeys now (one inside, and two on the cartridge). The two pokeys use about 10% of the Ultimate Cart's FPGA, so there is plenty room for more. This was just for fun, and perhaps to show a little of what is possible with a FPGA hooked up to the cart port. To make a proper external dual pokey, we'd probably want to use ECI+Cart port, so the pokeys could appear in the correct places in the memory map. MP3 of TMC playing via the dual pokeys attached. SynthyGambol_vhdl_pokey.mp3
  23. I wanted to try my hand at making a fun little utility, that programmers, whether they code in machine language, or 7800basic, could use to help them write commands to send to the POKEY chip in their own programs. It's a program that lets you set the volume, frequency and waveform settings for each of the POKEY's four channels, and hear what kinds of sounds each combination makes, to help you make music and sound effects easier. Kind of a "what you hear is what you get" sort of thing. I call it "Prickle", because the chip is called POKEY, and GCC was going to make a low-cost sound chip called GUMBY for the Atari 7800, so I figured I'd stay within that character set. This was inspired by Random Terrain's Tone Toy 2008, which I find is a great help for programming the TIA's two sound generators. When I started to think about adding POKEY sound and music to the game I'm working on, I looked to see if there was something similar for programming the POKEY. I don't know if I didn't look hard enough, or if there really wasn't anything like that (unless Raster Music Tracker counts?), but I couldn't find anything that worked like Tone Toy, so I decided to make my own, and share it with you guys, hoping that you might be able to use it, as well. Here's a screenshot of the interface. It's not much, but since it's more of a utility, I figured I'd draw up something basic. I am thinking about making it look a bit more graphical in a future update, though. Basically, you have a context-sensitive help bar at the top of the screen, which tells you what each of the joystick movements (and the fire button) do, at any given moment. All four channels are laid out, for you to tinker around with, until you find a combination of settings that you like. It starts out with the word one highlighted, and if you move the joystick up or down from that point, you can switch between the other four channels, as well. With any of the channels by themselves highlighted, pushing the joystick to the left or right highlights one of the channel settings, like volume, frequency and the waveform ("square wave", "sawtooth wave", "pink noise", etc.). With any of these highlighted, moving the joystick up or down will change that setting. It'll increase or decrease the volume or frequency, and in the case of the waveform selector, change the type of waveform. If you hold the fire button down while you do this, it will slow down the increase or decrease, so you can have a bit finer control over what you want to change each setting to. And, when you push the joystick to the left or right, so only the channel number is highlighted, you can press the fire button to mute or unmute that channel. I figured that might be helpful, if you're trying to program in a two-, three- or four-part harmony with the other channels, and wanted to adjust each one, without hearing the others, and without needing to turn the volume all the way down on each channel, first. This is version 0.9, which I put the finishing touches on about an hour ago. It's version 0.9, because aside from the idea of making the interface look a bit more graphical (and because I've been itching to try 320B mode out), there's one thing I'm not sure how to do, that I'm pretty sure might come in handy: 16-bit mode. If anyone knows how to do this, and would like to help me add it in for version 1.0, that would be great. I'm going to release this under version 3 of the GNU GPL, but if that's not a good idea, I can change it. Here's the attached files: prickle.zip contains all of the source files 7800basic generated, along with the font I used, the A78 and BIN files. I figured I'd include everything, just in case. prickle-v09.a78 is the program itself. I tested it under MESS, both with and without the XM, and it worked both times. I haven't tried it in ProSystem, but if it doesn't work for you (or it complains of no POKEY chip), please let me know. prickle-v09.bin is a BIN file, because I wasn't sure if anyone would wanna try this on a Cuttle Cart 2, or CPUWIZ's MCP development cart, while they're programming. Maybe I'm just being silly. ​ If you have any questions, the interface is too confusing, or you found a bug, please feel free to let me know. prickle.zip prickle-v09.a78 prickle-v09.bin
  24. Hello! I want to share some ATARI POKEY I made. These are both originals and covers, along with some behind the scenes. So, without further ado, I'm going to leaving this link here: https://www.youtube.com/watch?v=jgwcI3ATf3U&list=PLptR0gr8Js-44DoEDc_ZvYY6wlQWZZbcC Please, enjoy! I'm also looking forward to hearing from you all!
  25. How hard is to produce sound waveforms like in C64's sid music from games Driller and Dark side ? I'm interested in making a game that would use such spacy, trippy dragged sounds and would like to know how hard it would be ? Driller: Dark side: Mostly I want those sounds at beginning that look like square waveform.
  • Create New...