Monday, May 23, 2022

Getting new simgen backdrops on my amiga 500

This'll be nice and short.

I wanted to add some new backgrounds to simgen, which is a hack on Amiga Workbench 1.3 setups which allows for a 1 or 2 bpp (2 or 4 colour) background image.

Part of it is figuring out how to convert to a suitably formatted IFF (interchange file format) for an Amiga. I didn't want to install photoshop or do photo conversion on the Amiga. Yeah I'm lazy.

So the TL;DR is:

  • - rgb2amiga converts images to IFF using Imagemagick 6. Yes, make sure you install ImageMagick 6 as the latest version API has changed enough for this to fail compilation.
  • Make sure you resize the original image to a suitable resolution for your desktop - I'm using 640x200, and I'll play with 640x256 later.
  • Make sure you also realise the output screen is 4:3, so crop appropriately.
  • Run the program, and see what happens.
Here's the input and output images:

Yes I know I didn't crop it to the right aspect ratio; I just wanted to see if it worked before I spun cycles on optimising things.

Thursday, May 19, 2022

It took me WAY too long to get this gotek to work...

 The short version - when you buy an actual OG Gotek with the OG Gotek firmware, it doesn't work in any convenient way that is documented on any of the retro computing sites, because you DEFINITELY need to flash it with different firmware.

Ok, so the less short version!

I picked up a busted Amiga 500 for free to help repair an Amstrad CPC464 for someone. It had a busted ROM socket, busted RAM and some other random crap that I needed to fix. Oh and 50 of the keys were not working, and the key membrane was broken!

So everything above is fixed - and I still need to fix the RTC in the A501 memory expansion - but now I need to get it to boot. And I don't have a spare floppy drive for this.

But I did have a Gotek - I bought it for the IBM PC stuff, but I ended up bootstrapping it using USB 3.5 inch floppy drives.

.. and it didn't work. And I didn't understand why.

So, the summary.

I wanted to flash the FlashFloppy Gotek stuff from Easy peasy. Get a UART hooked up and connect to FreeBSD.

Didn't work. Welp.

After reading around I found that someone tried at 9600, because it just wouldn't work faster.

I did that and well now it does. It's quite possible if I added the 10k pull-ups mentioned on the flashfloppy hardware mods section that I'd have more luck.

.. and flashing it from FreeBSD:


Ok, next. Hooking it up. Set it to be device 0, remove another config jumper. Easy. Also, apparently the pinout is .. reversed on the amiga 500? In any case, pay super close attention to the orientation of the floppy drive connectors.

Anyway. Now it works. I then followed the installation instructions for a USB stick and whacked Workbench 1.3 images on - and now it boots fine into workbench 1.3. I've ordered a replacement mounting frame for the Gotek board so it can sit in with the case closed - but for now the machine works.

Well, besides the RTC. That's next. Ugh.

Saturday, May 14, 2022

Amiga 1200 - Kickstart 3.1.4 upgrade, but not upgrading to AmigaOS 3.1

 So I splurged a couple bucks on the updated AmigaOS 3.1.4 from Hyperion. It came with both the ROMs and AmigaOS. Now, I have 3.1 installed already, and I wanted to just drop in the ROMs.

It almost worked.

It looks like they moved some libraries from the ROM out to disk/RAM in order to make space.

So I figured they were on one of the installation disks, and....

Easy peasy. I copied icons.library and workbench.library to my system partition and rebooted. All good!

It's really quite slick how Kickstart ROMs are basically a bootloader and then a whole bunch of libraries, some of which form the core OS and some are actually just libraries. I'm sad this concept didn't show up elsewhere.