Crazyace

In some ways it would be more flexible, but it would still have had trouble keeping up with the PS1.

Ed was working on an expansion module and it's an early demo on that, I think. Don't think the module adds capabilities but does as RAM memory. One thing Opcode is amazing at is artwork. Even with the limits he's got, he churns out nicely polished games. Looking at the video - that CV1 isn't running on the Colecovision chipset, but a completely different graphics chip ( with hardware scrolling ) It would be pretty amazing if the original CV could do that

Have you emailed EA - just in case it's not actually an intentional problem, but an unexpected side effect.

If anything, that's an argument for higher sampling rates rather than lower, as you're only sampling a 2 bit grey code from the ST mouse for each axis. ( And maybe some filtering to handle noise )

The ST docs spec the mouse at around 200 dots per inch , with a maximum movement of 10 inches per second, which requires at least 2000Hz sampling - and you can't miss anything as it's easy to mistake backwards/forwards movement. ( On the amiga h/w converts the values to a delta count )

Actually it would matter for the programmer... and it would matter to the engineers if they wanted to design a cost optimized and fully integrated DMA+DAC audio circuit. From the programmer (and user) standpoint it would indeed matter if a plain PWM format was used as all samples would need to be converted to PWM formatting rather than PCM (not bare binary pulse values mind you -as that would take up far more space than PCM- but specific encoding that used words that decoded directly to PWM rather than normal signed/unsigned -or even sign-magnitude- PCM) Dont get the mechanism of PWM mixed up with how it was implemented in the 32X - it's pretty trivial to make a circuit that allows 0 to n-1 as the valid values rather than the 1 to n used on the 32X, or even one thats -n/2 to +n/2 -1. That's why I'm not hung up on how the audio is generated. I very much doubt that - and again you're ignoring the mouse sampling problem - it needs to be sampled at least 2000 times a second. ( And the circuit board design would now be very messy - as the keys would be decoded by 2 seperate circuits ) An analog mouse would also likely cost more than the wheel mouse and 6301. In the end I still can't see any reason to use POKEY in the ST - It has no redeeming features for the home/business machine that Atari made, and any custom silicon work to add things to it would have been far better used to make simple digital audio - as that would have tied in with the MIDI/music angle.

How it's implemented is still not actually that important, even a 12 bit off the shelf DAC - ( or at worst an 8 bit R2R ladder ) would be ok. I'd expect something hardwired in the same manner as the mac, rather than the much more complex audio found in the Amiga. STe volume changes aren't as quick as on Amiga, so you can't use the same tricks ( plus there's only one left & one right channel - so no mixing ) On the Amiga you can definitely get 14 bits , although the linearity isn't perfect

I think the Amiga was PWM in hardware as well - as I said the implementation isn't really important, just the fact that the sound is better than the AY POKEY is likely way more expensive than an ACIA - and are you sure the fast pot scan is really going to be a good audio ADC? I agree that a CIA would be nice to replace one ACIA+YM ( for the par. port and other controls ) , but ACIA+6301 is the cheapest/easiest solution for mouse/keyboard/joystick on a seperate board

Yes, true, but from an implementation/engineering standpoint it's different. From a programing standpoint, a PWM DAC could still matter as you could have a programmable sample rate and resolution selection dependent on the PWM master clock and not fixed like a resistor DAC -the programmer could choose to have higher resolution or higher sample rate as such, at least if the PWM circuit wasn't fixed to a standard output rate. (from what I understand, that's the way the simple PWM circuits are set up in the 32x and Game Boy Advance, both using directly PWM formatted samples, no PCM hardware interpretation to PWM and both set up by the programmer for the desired resolution/sample rate as such divided from the master clock -23 MHz in the 32x's case) Even STe style stereo 8 bit output would be an improvement on the AY, and be more comparable to the Amiga and Mac sound. 10 or 12 bit by whatever means is easiest in h/w would be amazing in music apps for drum machine/sample playback. I wasn't suggesting more chips, but less: ie instead of the ACIAs, YM2149, and 6301, just 2 CIAs or VIAs to do all of that (parallel keyboard/mouse) and use one of the VIA/CIA serial ports for external keyboard/keypad support. If there wasn't enough I/O lines on the 68901+VIAs/CIAs (VIA has more I/O lines) then you could still add a cheap PIA chip to supplement things (though that's the same footprint as the 6301, so component cost would be the primary advantage). It would be most significant if PIA was unnecessary though (just a 68901+2 VIAs -or CIAs- for all that I/O), with PIA the difference would certainly be less significant. Assuming you need an ACIA for MIDI anyway if you really wanted you could just use TTL latches for the keyboard On the ST the joystick/mice connectors were on the keyboard PCB though - so there was only the serial connection to the main board. Is that the design they used in the XEGS? No (XEGS wasn't serial ) .. it was only a throw away comment about the 7800 , not a new secret part of atari history.

PWM or a DAC - no real difference to the application programmer ( unless you are thinking of software controlled PWM which is a bit more insane ) - having more than 8 bits would make software mixing nicer though. Also why are you so set on removing the 6301? Do you know how much it cost compared to the multiple chips you use in it's place - Also, how will you handle the mouse control without it? If you polled the mouse directly from the 68000 you would need a sampling rate of 2000Hz at least - with no leeway for missed events due to interupts. Also if you look at the Atari documents the keyboard was designed to be used in multiple products - so I guess the external keyboard ( or even using it connected to the SIO of a 7800 ) would be possible with no real effort.

and regarding the 6301 again... Yes it does have the ability to multiplex it's bus - but that requires extra circuitry and loses you the general I/O lines that you want for the keyboard matrix. I'm guessing that the price was also cheap as a similar part appears in the amiga keyboard circuitry ( and IBM keyboards also used a microcontroller plus serial arrangement for keyboards ) You even mentioned the plus side, that it would allow a seperate keyboard without a wide fragile parralel connector. Regarding the 68901 - I think that the main function of it was as a 68000 autovectorising interupt device - it interfaced between the simpler 6800 class chips and generated the correct vectors so the 68000 wouldn't have to poll. And - having Pokey's would suck as they can't handle multiple key events, or mice , or even joysticks, and the serial use would require sound channels to operate. PWM would have been an option for implementing the sound output ( as it was on the Amiga ) - but if so it would have been best exposed as 16 bit stereo samples ( even if only 10-14 bits were valid ) in memory - That would have been something that would match the Amiga and also sell the Atari as a 'musicians machine' along with MIDI

I don't see why using an RGB monitor would make more resolutions any less desirable... it's not like you'd need a multisync monitor, just changing the dot clock (which has no impact on ana analog monitor as there's no limit on horizontal resolution as such other then beam precision and dot pitch), it's the same as a TV other than the use of direct RGB (and on top of that, higher beam precision and dot pitch -at least on the good quality monitors). If it increased complexity too much, then yeah, it would have been undesirable, but if it wasn't much to add otherwise, more horizontal dot resolutions would have been really useful in general (both for games and "serious" uses). The lowest res stuff would probably be limited to games for the most part, or maybe some specific art/graphics applications where high color depth was desirable at the expense of resolution... but for some other things the more moderately lower or higher resolutions could have been rather useful: especially for monitors fixed at normal NTSC/PAL calibration without external pots to adjust overscan. (at 8 MHz, you have very tall pixels in NTSC and hefty horizontal overscan... at 6 MHz you've got less visible pixels but almost perfectly square in NTSC... at 6.25 MHz you'd have perfectly square NTSC pixels and well over 288 pixels visible across -enough to reliably set that as the resolution without fear of overscan on TVs, so you could have 288x224 or slightly less vertically depending on NTSC calibration) In PAL, 8 MHz isn't too bad as it's pretty close to square as is the Amiga's clock (perfectly square PAL would be something close to 7.5 MHz), but you do have a hefty vertical boarder... but that's true for a ton of consoles/computers in PAL. (most master systems games would have played in something like 1.85:1 letterboxed ) And of course for RF/composite video users, the lower res modes would be even more applicable and more attractive for game developers as such on top of the lower resource for managing fewer pixels (and/or more practicality for higher depths)... especially in NTSC where the lower colorburst frequency causes artifacting sooner. That's actually a problem for the Amiga too with too tall pixels and composite/RF artifacting in NTSC... though in the case of games, they could at least depend on the artifacts being solid due to the 2x NTSC color dot clock. When the ST came out it didn't have any RF output , so the only way to use it was with the RGB or monochrome monitor. I like having 360/720 pixels as it doesn't involve any extra clocking options - just a slightly wider display. ( Thing's like multisync monitors were generally more expensive as well )

My guess is the design - after all, if you have to have extra logic to multiplex the keyboard and joystick/mouse inputs why not place those latches on the 68k side and save the cost of the 6301 and a 6850 ( I wonder what the cost of the 6301 was )

I dont know about lots of extra clocks - the ST was pushed for it's RGB output and Mono monitor , but it might have been nice to have 360/720 pixels ( like the hercules adaptor for the PC ) and 224/256 lines as that would still work on the 16MHz clock. ( Having 6 planes would be easy to implement - just more pallette entries , but dual playfield would involve more work ) Regarding the sound - of course if PCM and an AY were present some devs would use it, but it's extra cost for no real functionality. Having a single PCM mode like the STe and a faster cpu would allow mixing to only be limited by software. With the 6301 it does have the ability to run as a CPU ( with external address/data lines ) - but the version in the ST doesn't work that way- 24 IO pins are wired up as an 8 by 16 grid for keyboard scanning.

In the design of a new machine ( which the ST was ) adding an AY as well as PCM would have been stupid - it's redundant ( Genesis had the SN and the Z80 because of mastersystem compatibility, and SoundBlaster had FM for Adlib compatibility with PCM added ) Forget the 6301 - it was just a keyboard decoder/serial microcontroller, not a full cpu with external memory. No, it would not be cost effective - you would need a major redesign of the whole system, and lots of support chips to implement a dual processor 6502/68000 setup - especially with internal seperate memory. The ST already had a DMA circuit for floppy/hdd - so a second ( or even reuse of it ) for sound would be way easier.

The 68000 isn't on the bus every cycle - if you ran code with more ALU use ( long word ops, variable shifts and even multiply/divide ) the effective speed would be faster. With this type of memory architecture it would also make sense to allow shifter to be disabled, or allow different bit depths ( 320x200x2plane, 640x200x1plane ,(320x400x1plane for mono ) to give more cpu time. ( And also Atari could offer deeper bit depths without completely crippling the cpu - 320x200x6 plane , 640x200x3 plane for example - to be more competitive with the Amiga, as there would be more cpu time available in those modes compare to the Amiga )

You could run at 16MHz 68000 on 250ns DRAM - but then any dma/video would steal cycles from the cpu - ( but it would still be faster than the 8MHz part ) Yes - no point having an AY chip if you have PCM Either really expensive ( shared ram ) or completely pointless - the 6301 is connected via a 6850, so every byte sent is a 68000 IRQ - it's far far easier to just have a 8 bit DAC wired up to the 68000, or even a 10/12 bit DAC if one were available.

And it's probably easier just to put an 8 bit DAC where the 68000 can see it Given that the memory was running 2 accesses per 68000 bus access it would have been interesting if Atari had followed the 8 bit strategy and had a faster 16MHz 68000 with the video DMA stalling the CPU. So during active display the CPU would drop in speed, but in VBlank/non display ( or if the display was turned off ) it would run faster.

I think you have a misconception on how the 6301 exists in the ST - it's only connected via a serial link to a 6850, so there is no bus connection at all. Any kind of redesign with a 6502/RIOT would just be more expensive - especially if you start talking about 2K ram chips and bus sharing ( extra buffers ) - The cost of that would be far more productively used in just picking a faster 68000. Also POKEY and the AY chip are pretty similar types of sound chips - both look pathetic next to the Amiga sound ( or even Mac sound )

It's not just the stockpiling - but the manufacturing cost - It wouldn't surprise me if the AY was actually cheaper to buy than a POKEY. Atari should have had DMA sound / Scrolling ( STe style ) from day one - and used a 6522 ( or CIA ) instead of one 6850+AY chip to handle keyboard comms and the parr. port.

I was going to write a long reply - but then I thought that this has moved from the original topic to more of a 'what should the ST have been' - and the answer to that is obvious - the ST should have been the Amiga! No competition would have meant that all games would be written to use the hardware fully from day one - and Jack would price an ST/Amiga at the mass market rather than the high end that Commodore originally pushed it. Then, it would be interesting what form a STe/A1200 would be in 89-90 to compete more with VGA PC's and consoles. ( Or in a perfect would Jay Miner would stay at Atari and engineer the Amiga as a new console/computer to replace the A8/5200 machine - no 7800 , just a 256k Amiga with Rom cartridges to outclass the NES )

Can't argue with that MSX2 offered 256 colours in 1986. - so having a TT-lite in 89-90 as a succesor to the ST instead of the STe would make sense. Sprites are overrated. A 256 colour screen with a faster processor will make up for the lack of sprites - and 3D titles would perform way better on a faster machine. Not really by 1989 16bit and 8bit DAC costs had plummeted, even putting 3 stereo DACs with no DMA on the ST bus wired to give 6 channel mono or 3 channel stereo would have been fine. But after the STE disaster they didn't want to mess about with the ST and went down to £299 for ST RRP. A ludicrous price for such a machine really...a C128 plus disk drive cost more I think in 1989! PC-Engine only has 5bit sound and the max frequency is 33% that of an Amiga, nothing special at all really and samples are pathetic on it (play SF2 and see) The sound comment is related to the original ST. If there was sound support a 16 bit version of the STe sound would have been the best for a TT in 89-90, and 4/6/8 channel mixing would just be software. Certainly was the option, launch with 8mhz, and then 12mhz + DAC for audio in 86/87. And 16 mhz in 88/89. The Amiga 500 didn't even start selling in appreciable numbers until 1988 anyway. That would be splitting the market again - forget the Amiga , just have a single , more competitive model of the ST - and games would be better In 89 Amiga's were running from slow+fast memory - and I think you must be referring to 640x200x16 being slow - 320x200x64 still left a good number of cpu memory slots free. The point is that a 'new' Atari machine in 89-90 that would be TT spec would offer performance to compete with both cheap PC's and game consoles. Maybe a faster CPU, on a 32bit bus and with a 68881 @ something like 33mhz. The DSP is the only thing that worked, and it was intended for sample playback/recording tricks like direct to disc or echo/reverb effects etc NOT as a replacement for the 68881 or as an aid to 3D games. And there is no point putting a 33mhz 68030 on a 16bit bus anyway let alone a 33mhz 68881 FPU. DSP is there because the bus is 16bit and it's the only way to make the Cubase/Steinberg dream machine they wanted. A 32bit design bus version of Falcon with an 040 or faster 030 is what Atari needed (which they cancelled in favour of Jaguar!) and Commodore needed to push with the Amiga 1400 with 28mhz 020 and CD-ROM as standard and chunky to planar hardware conversion, in the same Mega style case as 040 Falcon prototype, which they couldn't do because they wasted money on the CD32 project which bombed...surprise surprise!. A1200 and Falcon looked like bloody STFM and A600 toy cupboard (by 1993) level machines...this did them no favours sitting next to Apple and PC 3 box designs which conveyed a certain amount of professionalism. They both chose not to go with their last prototype home machines in favour of games consoles and promptly went bankrupt! 93 was too late - A new machine should have been there to replace the STFM in 89, with the 'power without the price' philosophy. A 16-20MHz(if earlier the ST had been 10MHz) 68030 would be enough if the price was less than $999

I dont think a closed box was a problem - the ST ( and Amiga ) were succesfull as 'games' computers as much as serious computers, and partial upgrades would have fragmented the market for the ST before it became estabilished. Scrolling shouldn't have made much difference to the development of shifter. 256 colours would have though ( I dont think any GTIA comparisions would be viable - shifter is actually a lot simpler than Antic/GTIA ) Packed pixels vs planar is a minor inconvenience for programmers - but it has no effect on capabilities, so it's not really that important - and for non game use planar is actually better ( monochrome to colour expansion is easy via duplication of bitplanes for example ) I agree - but for a TT in '90 with a VGA connector it should have had a 18bit pallette to match VGA Sound wasn't as much of an issue as scrolling - and adding any sound h/w would have a far greater impact on the design time and cost I'm not sure 12MHz was practical in '85 - 10MHz would have been top in terms of keeping the same memory model. ( 200ns memory compared to 250ns ) VGA offered 640x480x16 colours at 18 bits , and 360x480x256 colours via direct register hacks. The Amiga had 640x480ix16 colours and 320x480ix64 colours ( and HAM of course ) - so a real upgrade would be needed for the base ST in '90 - and the TT modes almost had it ( the Falcon modes were better ) I think just having a faster CPU would be much better than a DSP - it may not be as fast, but it's much more general.

I think upgrading the ST is a mistake - the ST was a fixed platform and any improvements should have been in the original model. Otherwise software would just ignore it ( look at how most games were on single sided drives ) That's why I push scrolling - it gives the best 'bang for the buck' and really doesn't involve very much change to shifter at all. Making the cpu speed 10MHz rather than 8MHz would be another possible for the launch. Then in 1990 release a replacement machine ( cut down TT? ) with TT style graphics + VGA support, maybe with 16/20Mhz 68030, as a low cost ( rather than high end ) machine, emphasising compatibility with all ST software - so people upgrade to that machine. ( or even 2 models - low end 16/20Mhz 68000 , high end 33-40Mhz 68030+expansion )

It wasn't that difficult to make an STe version of a game, but it also really wasn't worth it. The ST should have had the scrolling ( forget sound, as that would have been a much bigger redesign - and the win wouldn't have been that much ) from day 1. Then when the TT was announced the pallette should have gone to 6 bits per colour channel ( 262144 colours ) and a STe should have been a 16Mhz 68k with TT video modes ( and VGA monitor support ) That way there would be a high end machine and a 'new' base games/home platform.