Posts by mega65

    So quite likely the problem is the audio in the signal. I had previously missed that your monitor is DVI only.

    Now, there may be a work-around for this problem, in that we can instruct the MEGA65 to produce a bare DVI signal, without the audio or data islands etc.

    From the Matrix Mode monitor, try:

    sffd361a 2

    This should switch from HDMI-compatible to DVI-compatible display.

    Let me know if that works.

    (In theory, we can make the MEGA65 auto-detect if the monitor is DVI or HDMI, but haven't implemented this. I'll take a look at what would be involved to achieve this.)



    Almost everything with good performance on the C64 is "weird" or "custom" in some way, so I don't think you need to be too afraid. In fact, Shallan is making a D81/floppy fast-load framework that works without the C65's ROM, precisely so that he can use all 384KB RAM. This would probably also solve your need, and you can then use something that someone else is maintaining, and thus make your life and conscience easier :)




    Sorry to hear of your battles here. Some thoughts:

    1. MEGA65 can move ZP around the place as well, which should solve your ZP pressure problem.

    2. You don't need a whole new OS, just a DOS library that can read D81 disk images and let you seek around in files.

    3. With (2), and if you don't use the C64/C65 KERNAL calls, you actually can get almost all the ZP back, anyway, which might relieve (1).

    So don't give up hope just yet!




    I love your work on this, and it would be great to see it running natively on the MEGA65. A few general comments as I go along:

    1. For 32-bit arithmetic, you can use the MEGA65's CPU extensions. The already documented extensions in the MEGA65 Book can be considered "rather unlikely to change". They were partly designed to make compiled high-level lanugages much more efficient than on a stock 6502.

    2. Yes, CBM DOS sucks quite a lot. You would probably be best to make your own DOS layer that can trace through the file sector chains to allow random seeking. The MEGA65 Hypervisor also provides access to native FAT32 files, but also currently lacks a SEEK call, although one is planned.

    3. You can move ZP on the MEGA65 using the TAB instruction if you need to deal with ZP overflow.

    Anyway, keep up the great work, and I look forward to seeing it in action on the MEGA65!



    It's also possible that the SD card is wonky for some reason. Please try getting a new SD card, put it in the MEGA65, use the ALT key on power up to format in the MEGA65, then copy all the files from the old SD card onto it, and try that.

    Otherwise, is it hot in your work area? It is possible, but unlikely, that the timing closure problems in the bitstream + heat + a marginal bin FPGA are enough to introduce some instability. We have mostly dealt with the timing closure in the latest experimental bitstreams. So if this is the problem, it should go away with these newer bitstreams.

    So that's a couple of different approaches we can try.


    You did F7 and chose to save the new settings, right? Until saved once, you will be stuck in NTSC, even if it says PAL. We know about this, and will do something about it.

    Please try this one for the mouses:…testers/8665-mouse-test-2

    You should enable the 1351 emulation for Amiga mouses option. If you only use the mouse in a given port, you can set it to "aggressive".

    Let me know if the 1351 indicator moves or the Amiga one.



    The N4 boards use the keyboards in a braindamaged "backup" mode, and only enumerates the very first device on the bus it finds. This means the keyboard must not have any USB stuff like hubs or other ports, and must be able to work in BIOS on old early-USB PCs (since that is the mode they use the keyboard in).

    Now, as for MEGA MAZE problems etc, which bitstream are you using? Head of 138-hdmi-audio-27mhz?



    The program runs great under the mega65. Could you access the date in C64 mode?

    You could adapt this program to work from C64 mode, yes. "Left as an exercise to the reader".

    There are still problems in the configuration menu. In my opinion the time is not read correctly from the RTC. After 11:59.00 comes 32:00.01 ? After 23:50.00 comes 24:00.01 ?

    Once the menu has been saved you can no longer access the device. Only after switching it off and on again everything works again. Maybe Paul has a good idea again.

    Yes, this is because the values are BCD, with $20 meaning PM. Log an issue on It wouldn't be too hard for someone with some 6502 skills to find and fix.