80 columns

v0.00009

This prerelease adds, compared to v0.00007:

• 80 columns of text. Enabling this option automatically enables the CRTC too, but you need to load the 8032b.rom yourself. You will also need to enable the following new feature:
• B-type ("business") keyboard. By itself this is not so interesting, since with the symbolic mapping of the Mega-65 keyboard you don't notice much difference (but do refer to the keyboard mapping section below).
• 2001-style screen snow. This is enabled as part of "2001 screen blank etc". This option affects 2001-specific quirks as part of the "etcetera". At his time they are:
  • screen snow, when the CPU accesses screen memory at the same time as the video system.
  • the screen blanks when EOI is sent on the IEEE-488 bus. This is used by the ROM to mask the previous effect when scrolling (only the non-CRTC ROMs do this).
  • the 1 KB of screen memory $8000-$83FF is repeated 3 more times, up to $8FFF. Later models go only up to $87FF.
• I have extended the set of ROMs with B keyboard and 80 column ROMs. You can get more variants from the well-known Zimmers site.
• I am including a petcfg file which you can copy to the /PET directory on the sd-card. It will remember the menu selections. Unfortunately not the ROM file you loaded, so it is less useful than it could be.

Add CRTC

This version adds an optional CRTC.

Note that if the CRTC is enabled, it should be initialized or your screen will look weird. So you also need to select a ROM set which supports the CRTC, such as v0.00005/4032n.rom from the v0.00005 pre-release. And then press the reset button. This romset will also work if you don't have a CRTC but then of course you don't get the extra text spacing in lower case mode. Note also the changed aspect ratio of the text; this probably somewhat corresponds to the "fat-40 experience".

Tested with the timing programs from VICE bug #1954, and the A Bright Shining Star demo.

Video timing is now good

Racing-the-beam programs for CRTC-less models now work.
See test programs at VICE bug https://sourceforge.net/p/vice-emu/bugs/1954/ or PET's TRIP https://www.pouet.net/prod.php?which=95051 .

Cores for R3 and R6 included. See previous releases for ROM files etc, I'm not currently repeating them.

Loadable ROMs

I added some items to the menu and some of it even works. You can now load ROM sets; I added a few in the zip file.
For a true 2001 experience, turn the screen white-ish, enable screen blanking on EOI, load the 2001 character set (different in lower case mode!) and the 2001 ROMs. Too bad you can't reduce the memory size to 8 KB yet...

Now with sound!

Now with sound, which includes a generous amount of low-pass filtering. Otherwise you'd hear a high whine when many programs think they have turned off the sound (they merely set it to the highest frequency which typically wasn't audible on the speakers as used).

Enjoy Dromeda with sound, making it multi-media avant la lettre! (It moves and has sound, so: multimedia!)

Floppy writing now works

Writing to floppies now works.

I include a core with 2 drives, so you can see how mounting a disk image sometimes/often(?) results in a garbage directory listing but sometimes unmounting and remounting works. I tend to think this is an M2M problem, not a core problem.

Sound is still missing.

megapet-v0.00003a.zip is a 2-drive core for the Mega-65 R3 board revision.
megapet-1drive-v0.00003a.zip is a 1-drive core for the Mega-65 R3 board revision.

v0.00002

Has one 2031 disk drive. Writing to disk doesn't work, but I don't know why.
I wanted to include 2 disk drives but then there seems to be confusion about if a disk is mounted; directory listings can show garbage, or sometimes work. Sometimes the menu thinks no disk is mounted but the drive disagrees.

Absolutely minimal proof of concept

pet2001_m65_r6_v0.00001.zip

For some reason the display flashes while scrolling.
Don't try to access the IEEE-488 bus, there is nothing there and it will hang (which should of course not happen).