Updated Apple II plus core for the MiST

I’m still not completely happy with the mockingboard implementation but one can play with it and if it doesn’t work nicely just turn it off (it’s off per default).
Skyfox starts playing music but hangs later which doesn’t happen when the mockingboard is turned off. Another bug is that from time to time I just hear statics and a new recompilation under Quartus fixed that. So something with the timing might not be okay. I’ve added a .sdc file which made it a little bit more stable but I’m open for hints on how to stabilize it.

I fixed another issue which annoyed me lately. When doing a reset the Apple II preserves it memory and software is able to alter the reset vector. At memory $3F2 and $3F3 the reset address is stored and when altered a reset brings you to the prompt (at best) or just hangs somewhere and you can only turn off the MiST. If $3F4 would be a random value and not the XOR between $A5 and $3F3 the Apple II would “think” its a cold boot and starts the Autostart ROM.
I just set $3F4 to zero when the cold boot option in the osd is pressed and the Apple II resets and tries to start from disk.

4 thoughts on “Updated Apple II plus core for the MiST

  1. Ray says:

    Love your work!
    I’m able to play many of the games I played during my childhood. Unfortunately one of my favorite games does not work… Serpentine. Would be great if a new core could make that game work!

    • WiSo says:

      Thanks. But I’m not the author of the core. I just ported it to the MiST and added some things. Also I’m a little out of business and thus would need time to learn it again. I would love to work again with fpga’s but don’t have the time currently.

  2. Jennifer Pierce says:

    Love the APPLE II port! Any chance of getting the writing back to disks working??

    Jennifer

    • WiSo says:

      Thanks. Back then I tried to implement writing but didn’t succeeded. Its long ago that I’ve spent time in fpga development and forgot most of it. I hope that someday I’ll have some time to proceed with it.

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