+warerat Posted October 13, 2008 Share Posted October 13, 2008 i have a question. if i were to add 2 more POKEYs to Metalguy's design, could i connect the A4 signal to pin 2 of the 74LS14 and then at each subsequent output of the 74LS14, i.e. pins 4,6 and 8, connect pin 31 of each POKEY? also, i would have to bridge pin 4 to 5 and 6 to 9, correct? i tried to make an illustration of what i mean... [edit]illustration attached. go easy on me because i don't have an electronic engineering background and i'm just trying to figure this out as i go! i would assume that the audio out of just 1 POKEY would be enough to supply the +5Vcc that the hex/schmitt trigger needs...? also, would i just connect pin 17 of all 4 POKEYs to pins 13 and 1 of the 74LS14? thanks for any help! Yikes... Don't do that. Ever. You have to decode more address space to get four unique selects of 16-bytes each. One way to do is this to toss the 'LS14 and use half of a 74LS139. All POKEYs will have pin 31 tied to +5V, and common address/data/power. You'd need to get A4/A5 elsewhere on the motherboard. The pot, interrupt, keyboard, and SIO pins shouldn't be connected-- except on the first. And naturally audio output would be unique on each. 74LS139: Pin 1: D0XX- select (get this from pin 30 coming from the original POKEY socket on the motherboard) Pin 2: A4 Pin 3: A5 Pin 4: To pin 30 on POKEY 1 Pin 5: To pin 30 on POKEY 2 Pin 6: To pin 30 on POKEY 3 Pin 7: To pin 30 on POKEY 4 Pin 8: GND Pin 16: +5V Quote Link to comment Share on other sites More sharing options...
athleos Posted October 13, 2008 Share Posted October 13, 2008 (edited) i have a question. if i were to add 2 more POKEYs to Metalguy's design, could i connect the A4 signal to pin 2 of the 74LS14 and then at each subsequent output of the 74LS14, i.e. pins 4,6 and 8, connect pin 31 of each POKEY? also, i would have to bridge pin 4 to 5 and 6 to 9, correct? i tried to make an illustration of what i mean... [edit]illustration attached. go easy on me because i don't have an electronic engineering background and i'm just trying to figure this out as i go! i would assume that the audio out of just 1 POKEY would be enough to supply the +5Vcc that the hex/schmitt trigger needs...? also, would i just connect pin 17 of all 4 POKEYs to pins 13 and 1 of the 74LS14? thanks for any help! Yikes... Don't do that. Ever. You have to decode more address space to get four unique selects of 16-bytes each. One way to do is this to toss the 'LS14 and use half of a 74LS139. All POKEYs will have pin 31 tied to +5V, and common address/data/power. You'd need to get A4/A5 elsewhere on the motherboard. The pot, interrupt, keyboard, and SIO pins shouldn't be connected-- except on the first. And naturally audio output would be unique on each. 74LS139: Pin 1: D0XX- select (get this from pin 30 coming from the original POKEY socket on the motherboard) Pin 2: A4 Pin 3: A5 Pin 4: To pin 30 on POKEY 1 Pin 5: To pin 30 on POKEY 2 Pin 6: To pin 30 on POKEY 3 Pin 7: To pin 30 on POKEY 4 Pin 8: GND Pin 16: +5V oh man! thanks for the reply! i wish i understood this stuff. i'm glad i didn't try it before i asked! [edit] for pin 31 on all POKEYs, would i just connect pin 31 of the original POKEY or POKEY "A" to pin 31 on the other 3? also, in my original post, i meant pin 30 for connecting to the LS14 not 31! sorry! Edited October 13, 2008 by athleos Quote Link to comment Share on other sites More sharing options...
atariksi Posted October 13, 2008 Share Posted October 13, 2008 ...All POKEYs will have pin 31 tied to +5V, and common address/data/power. You'd need to get A4/A5 elsewhere on the motherboard. The pot, interrupt, keyboard, and SIO pins shouldn't be connected-- except on the first. And naturally audio output would be unique on each. 74LS139: Pin 1: D0XX- select (get this from pin 30 coming from the original POKEY socket on the motherboard) Pin 2: A4 Pin 3: A5 Pin 4: To pin 30 on POKEY 1 Pin 5: To pin 30 on POKEY 2 Pin 6: To pin 30 on POKEY 3 Pin 7: To pin 30 on POKEY 4 Pin 8: GND Pin 16: +5V Why isn't the interrupt (IRQ) connected? I use the POKEY more for timing and SERIAL INPUT so a dual serial input port and more timer IRQs would be very useful. Just like you have a connector for audio, you can have a connector for another serial port (at least one pin for serial input). The programmer can set it up so the serial INPUT interrupts are interleaved in such a way so they don't occur at the same time and thus have two serial streams inputting in parallel. Similarly for the timers. As long as the second POKEY is not programmed to generate interrupts, the second POKEY should function like it's already doing. Quote Link to comment Share on other sites More sharing options...
athleos Posted October 13, 2008 Share Posted October 13, 2008 this is for 4 POKEYs and as far as i'm concerned, it's solely for audio purposes... i'm sure having more serial options etc would be nice but i don't think i'd have much use for them. i'm just expanding to have more voices for my POKEY music. Quote Link to comment Share on other sites More sharing options...
MEtalGuy66 Posted October 13, 2008 Author Share Posted October 13, 2008 There is already some software (at least one tracker, and possibly some demos as well) that supports "QUAD POKEY".. What I dont know is how the 4 pokeys are decoded. If I was to expand the board design to handle 4 pokeys, Id need to know this, and I think its to everyone's advantage to adhere to whatever standard has already been supported here. Does anyone have a link to a document describing the existing "quald pokey" upgrade? If I was to make another board, I'd add a few things also.. Many have said that they wished the board had a Preamp so that they could plug headphones directly into the ATARI. There are a whole bunch of realtively cheap "1 chip solutions for this. I'd also put the attenuation (trimmer) pots on-board so you could "dial in" the exact relative output levels of each channel to suit the needs of whatever equipment you are outputting the audio to. Also, if I was designing a quad-pokey board, I'd include jumpers to select whether you have 4 separate 4-voice output channels, or 2 mixed 8-voice stereo channels... The guy using it in a studio-type setting (eg. with an external mixing console/track recorder) may want the 4 separate channels, while the average person just wanting to LISTEN to it would probably want stereo outputs for use with common multimedia speakers, stereo systems, or (as stated above) even headphones. Quote Link to comment Share on other sites More sharing options...
athleos Posted October 13, 2008 Share Posted October 13, 2008 yeah, i plan on having 4 individual outs. i was actually curious how the 4 POKEYs were decoded as well. i know that with Theta Music Composer 2, your design for the dual POKEY board works perfectly so i figured if i were to expand that to 4 it would decode in the same way. the guys over at elektronforge.com have a quad POKEY eliminator board that they sell but i can't find any info on the schematics for something similar nor can i find out how they're decoded... i just figured warerat knew what he was talking about and i'll try that design and see how it goes. also, i just want you to know that i'm only breadboarding this and the farthest it would go would be 1 protoboard version in my 800XL. i don't plan on stealing your or anyone else's thunder, i just didn't want to wait around for someone else to do it! thanks for your work metalguy! Quote Link to comment Share on other sites More sharing options...
atariksi Posted October 13, 2008 Share Posted October 13, 2008 this is for 4 POKEYs and as far as i'm concerned, it's solely for audio purposes... i'm sure having more serial options etc would be nice but i don't think i'd have much use for them. i'm just expanding to have more voices for my POKEY music. My point also applies to 3+ POKEYs. You can still have a SERIAL IN pin on there and enable IRQs without much effort and it'll be there if someone wants to use it. Timer IRQs and SERIAL IN can also be used for audio purposes. In fact, if those softwares that write to the repeat locations of POKEY, they would be more compatible in a 2+ POKEY setup and it should have no effect on software that uses 2+ POKEYs the way they are now. Quote Link to comment Share on other sites More sharing options...
MEtalGuy66 Posted October 13, 2008 Author Share Posted October 13, 2008 (edited) yeah, i plan on having 4 individual outs. i was actually curious how the 4 POKEYs were decoded as well. i know that with Theta Music Composer 2, your design for the dual POKEY board works perfectly so i figured if i were to expand that to 4 it would decode in the same way. the guys over at elektronforge.com have a quad POKEY eliminator board that they sell but i can't find any info on the schematics for something similar nor can i find out how they're decoded... i just figured warerat knew what he was talking about and i'll try that design and see how it goes. also, i just want you to know that i'm only breadboarding this and the farthest it would go would be 1 protoboard version in my 800XL. i don't plan on stealing your or anyone else's thunder, i just didn't want to wait around for someone else to do it! thanks for your work metalguy! Thats totally different.. The "Quad pokey eliminator" board takes the place of a "quad pokey chip" and lets you use 4 individual pokey chips.. This is for coin-op arcade boards and has nothing to do with the 8-bit atari. You see, ATARI used to make a chip that had 4 pokeys in a single chip. It was used in coin-op arcade games. This chip is EXTREMELY hard to find nowadayze, so they make a board that lets you replace it with 4 indicidual POKEYs which are atill commonly available.. Warerat does know exactly what he's talking about. But what I am saying is that if you want compatability with existing software that has already been written for QUAD POKEY arrangements, you better make sure your design is decoding the Pokeys to the same adress ranges. I think what warerat did is give you a suggestion of how you COULD do it, he may not have researched how it was done in the past. As I said before, there is at least one tracker and probably a few demos and other apps that support 'QUAD POKEY' already.. Edited October 13, 2008 by MEtalGuy66 Quote Link to comment Share on other sites More sharing options...
+warerat Posted October 13, 2008 Share Posted October 13, 2008 The circuit decodes as: POKEY 1: $D200-$D20F (this has the primary and has all the features connected) POKEY 2: $D210-$D21F (only data, address, clock) POKEY 3: $D220-$D22F (only data, address, clock) POKEY 4: $D230-$D23F (only data, address, clock) (repeats 4 more times) This is why you uniquely connect pin 30 on the four chips to the decoder, and not the motherboard socket pin 30. Pin 31 on all of them should be tied high. Quote Link to comment Share on other sites More sharing options...
athleos Posted October 13, 2008 Share Posted October 13, 2008 (edited) @metalguy: well, seeing as we've already established the fact that i have know clue what i'm talking about, i guess i'll just move ahead and report back my findings! i can only assume the worst that could happen is 2 of the 4 POKEYs just don't make a peep. if this happens, well, i guess i'll have to disassemble the code for the program i'd be using and figure out where all 3 extra POKEYs are being addressed. from there, i would have no idea what to do... i guess i need to study up on how the 6502 works and continue learning machine language. as i said before, TMC2 seems to have no problem with the second POKEY in your design so i can only assume the 3 and 4 would be 16 and 32 bytes above that... but again, i have no clue what i'm talking about. @atariksi: sorry man, i really have no clue what you are talking about! i wouldn't know what to do with extra serial ports if i had them. i'm pretty new to this whole thing. i'm just a composer/musician! [edit] for being an idiot Edited October 13, 2008 by athleos Quote Link to comment Share on other sites More sharing options...
atariksi Posted October 15, 2008 Share Posted October 15, 2008 How much cheaper would a Gumby Board be if I just bought a blank PCB? I already have all (ok most) of the components. I have got 2 of the original boards for sale (un-populated) make me an offer. Is it easy to enable the IRQ on it for the 2nd POKEY? Quote Link to comment Share on other sites More sharing options...
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