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RevEng

Member Since 23 May 2009
OFFLINE Last Active Today, 9:25 AM

#4133247 Happy New Year... XM shipping this month

Posted by RevEng on Sun Oct 14, 2018 9:13 AM

[...]Leveraging the POKEY chip inside the XM for address space $4000 (AKA "standard") POKEY support, does not seem to be an impossible task, but would definitely add another layer of logic complexity to the XM BIOS.


Thankfully there's no need. It would take a few minutes to create patched BallBlazer and Commando images that use POKEY@450.


#4129779 Sound FX Library

Posted by RevEng on Mon Oct 8, 2018 5:33 PM

The "soundtest" program in the 7800basic samples directory has 25 different sound effects. You're welcome to use them as-is, or modify as you see fit.

I don't believe anybody else has released a TIA sound-effect library, for the 7800 or 2600.


#4125659 [Very odd scanlines problem!] Strange B&W effect in game

Posted by RevEng on Tue Oct 2, 2018 7:08 AM

When the playfieldpos transitions back to 0, it does a coarse scroll. This is expensive cyclewise, because a bunch of memory has to be moved around. Here's another thread on it.

You're doing the right thing, trying to eliminate cycle overages by skipping stuff, but it needs to be on the frame prior to transitioning to 0, IIRC.


#4125425 Chord experiment

Posted by RevEng on Mon Oct 1, 2018 7:37 PM

Related reading: TIA Arpeggio Tips :D


#4123779 Working on Mega Man clone for 7800

Posted by RevEng on Sat Sep 29, 2018 2:24 PM

Any chance for show+tell with your 7800 WIP? I think the crowd would be thrilled to see any of your screens, even without the sprites.


Just leaving the above here, in case you missed it the first time around. Throw the crowd a bone. :)

I know you mentioned you only had unfinished game demos for the 2600 and inty (still would love to see them!) but what about your Colecovision Outrun WIP? Would be great to see it in action, even with the speed problem. Pretty sure we'll be amazed!


#4123299 Working on Mega Man clone for 7800

Posted by RevEng on Fri Sep 28, 2018 9:07 PM

Curt Vendel advised that after XM is done, he has plans to do an ASIC run of pokeys. This should be much more affordable than FPGA.


#4123187 Spire of the Ancients (WIP)

Posted by RevEng on Fri Sep 28, 2018 5:45 PM

Thanks, Mitch! I'll look at adding support for that to 7800basic.


#4123008 Baby Pac-Man

Posted by RevEng on Fri Sep 28, 2018 1:05 PM

Based on his frustration in recent posts, and the other times he's left, I'm pretty sure Bob is on a break.

The good news is, he just said he was out of this game, and didn't make any permanent comments on the hobby. People should give him the space he clearly wants, and just keep the home fires burning. When it can be a fun hobby for him again, he'll likely return.


#4122922 Working on Mega Man clone for 7800

Posted by RevEng on Fri Sep 28, 2018 11:15 AM

They weren't full games just some demos. Those were made some time ago, I decided to try and make an actual game on the 7800 since it gives me the graphical power I need to really create a world. Not that the 2600 can't do that, but I think it's too limited for the vision I have in mind.


Ah, too bad. Each dev has a unique style that you can sometimes pick out, even with different platforms. I was hoping for a preview of yours. :)

Any chance for show+tell with your 7800 WIP? I think the crowd would be thrilled to see any of your screens, even without the sprites.

I think TIA audio is a good place to start. You could later add "pokey enhanced" features, if you change your mind. That way you're still covered, if the current pokey famine continues. I'd hate for your game to be only available for those who can supply a pokey.


#4122350 AtariVox+ Few oddities

Posted by RevEng on Thu Sep 27, 2018 1:32 PM

I'm glad you have a workaround, John. The 6 second grace time is a bit of a shame, but workable. If we can't get to the bottom of this, I'll probably impose a similar limitation on the 7800basic vox driver.

Thanks for the offer of help. I'll keep it in mind. You've already helped by giving us independent confirmation that this happens on the 2600. One of the questions I've been asked multiple times is "why doesn't this happen on 2600 atarivox games?". Thanks to your report (and the 2600 test I wrote) we know it can.


#4122183 AtariVox+ Few oddities

Posted by RevEng on Thu Sep 27, 2018 9:54 AM

If you're game, when you get a chance can you please hook up the vox, light up the 2600 test, trigger the phrases, and check out the following?
  • Probe +5v=joy2_pin7 with ground=joy2_pin8. Observe if the signal is flat at various scales, and the voltage level is constant, even when you stuff the buffer. (first with joystick button phrase triggers, and later with joystick moves)
  • Probe speakjet_ready=joy2_pin2 (same ground). Observer if the signal is flat, and transitions when you stuff the buffer. (first with joystick button phrase triggers, and later with joystick moves)
I get that it's an analog scope, and you won't be able to check the quality of transitions. Just fishing with the gear we have access to.

The pinout below is for your convenience.

Joytricks5.jpg


#4121927 AtariVox+ Few oddities

Posted by RevEng on Wed Sep 26, 2018 8:34 PM

Hi John,

I wish I had better news here, but I've had no success addressing the issue from the 6502 software end.

It looks like the RIOT pin connected to D0/Ready line doesn't get the signal change in time (or perhaps, not every time) to prevent the AtariVox buffer from getting stuffed.

As to why, it seems worse when there's joystick action involved (other RIOT pins being grounded). But changes in an individual's power adapter, console, and AtariVox, don't provide relief. Similarly, people who don't experience the problem, don't experience it on multiple consoles and power supplies.

I've tried only sending bytes every other frame, but that didn't eliminate it. I've tried adding a secondary software queue, but it was too difficult to accurately track the phoneme lengths. I've eliminated perceived "problem phrases", but that didn't eliminate the issue. I've tried tweaked baud rate from the 7800 driver end, with no relief.

I'd really like for someone with the issue to scope the power, ground, and RIOT pins involved, to look at the quality. A logic trace of the buffer getting stuffed would be nice too. So far nobody with the issue has a scope or necessary skills, nor do they have a UPS to rule out external power quality.

That's the state of the union, sad as it is.

Cheers,
-Mike


#4121553 Baby Pac-Man

Posted by RevEng on Wed Sep 26, 2018 12:01 PM

I don't think you said anything insulting or offensive, Kurt. You just explained why you used a bunch of temp variables. I'm neurotypical, and it didn't come off as blaming to me.

If anything, my suggestion may have been the last "helpful" straw that broke the camel's back. Sort of thinking that's the case, based on the "plethora of other programmers" comment.

Let's leave it alone for a while. Even if Bob doesn't want to finish it, I think it's best to let everybody sleep on it, before anybody talks about picking up the pieces.


#4121415 4K VCS Assembly Programming Competition

Posted by RevEng on Wed Sep 26, 2018 9:25 AM

I agree with s0c7 and Karl G. The length of time is too short (IMO 6 months with regular warnings would work better) , and the fake label requirement constrains the coder too much.

I'm also not planning to join in, so use a heap of salt on my words too. I greatly appreciate what you're doing, but my time is short and money isn't the motivation. That's probably a good thing, since you're trying to encourage new blood.

If it were my rodeo, I might build this contest around a multi-cart instead, with the top 3 entries going to the cart. (3x 4k banks, and one for the menu). Give it a loose theme, and a guarantee of personal cart and manual for winners. Budget a small run of carts, and if there's anything left, figure out prizes from that. You might even be able to fund the contest with the proceeds from the limited cart run, and do it every year.


#4121388 Happy New Year... XM shipping this month

Posted by RevEng on Wed Sep 26, 2018 8:33 AM

Thrilling news, Curt. Joe Decuir involved too? Mind blown!