Jump to content

Recommended Posts

7 hours ago, RevEng said:

This sort of problem with flow control could either be a bad jump, bankswitch, or whatnot, or it could be a hardware issue. The fact that the problem with Popeye didn't manifest when Versa was used, demonstrates it's a hardware issue in that case. Perhaps it's the same here too, since many people can't reproduce it.

 

But a hardware issue where? The 7800? The DF cart? That is what we are trying to figure out. The fact that @john_q_atari has this happening to some degree on 3 different 7800s that he has in his possession would indicate it isn't the 7800 as it is unlikely that he would own three of them with the same hardware error right?

  • Like 1

Share this post


Link to post
Share on other sites
12 hours ago, -^CrossBow^- said:

But a hardware issue where? The 7800? The DF cart? That is what we are trying to figure out. The fact that @john_q_atari has this happening to some degree on 3 different 7800s that he has in his possession would indicate it isn't the 7800 as it is unlikely that he would own three of them with the same hardware error right?

Yes, that's the question, and there isn't a simple answer here. The 7800 has some signal quirks. e.g. A14+A15 being pulled up, A12+A14+A15 being run through AND gates before hitting the cart port. (introducing differences in timing between these lines and the others) Bus access happens at 1.19Mhz, 1.79Mhz, and 7.16Mhz, depending on what device is involved. Probably more that I'm not considering. Timing with these quirks, even with eprom based carts, has always been a bit hit and miss.

 

 I only wanted to add some clarity to the fact this likely isn't a software issue, since Versa is immune. I don't own a DF cart, and nor do I have the tools to do a signal timing analysis.

 

  • Thanks 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...