Minimig (Amiga) core discussion

[mambrino]

Yes, I have the same problem. Black screen on core boot and can't open OSD. In my case, seems to be related to cpu selection. 68020 AGA kick 3.1 works, but if I change cpu model to 68000 then core get stucked. I also noted that scrolls at 50hz keep stuttering.

[Threepwood]

I can confirm the problems, for me the core starts fine, my default configuration is 68020+AGA+Kick OS for Amiga 1200. When I try to load another configuration or change the config and reset, the screen gets a little bit smaller and the core hangs (I can still enter the menu).

My default is 68000+OCS+Cloanto_Kick_1.3 (512 Chip, 512 Fast).

When I manually change the default by copying the files around on my MiSTer, to use 68020+AGA+Kick3.1 etc. then it works. The core hangs here, too, when I then load another config.

[Sorgelig]

Got the same issue..
Will investigate it.

[tempus007]

The MINIMIG_20200504 core works on my side.
128MB
CRT
vsync_adjust = 2
68020 + AGA + Kick OS 3.1

[Threepwood]

The MINIMIG_20200504 core works on my side.
128MB
CRT
vsync_adjust = 2
68020 + AGA + Kick OS 3.1

Which is the same config that was already noted as working here. Have you tried an Amiga 500 config (68000+OCS+Kick1.3)?

[Sorgelig]

it's already known: 68000 mode doesn't run because halted. I will fix it.

[mambrino]

it's already known: 68000 mode doesn't run because halted. I will fix it.

in addition do you think would be possible to set the vertical frequency for pal mode to a value closer to the 50hz standard for smoother scrolls in some tv's and scalers?

Thanks

[Sorgelig]

in addition do you think would be possible to set the vertical frequency for pal mode to a value closer to the 50hz standard for smoother scrolls in some tv's and scalers?

Thanks

video mode on Amiga is programmable and it depends on specific game/app which refresh it outputs.

[Threepwood]

it's already known: 68000 mode doesn't run because halted. I will fix it.

I can confirm it is fully working again. Thanks a lot, Sorgelig. And thanks to Paulbnl for getting this core closer to reality with adjusting the vsync position, of course.

[mambrino]

video mode on Amiga is programmable and it depends on specific game/app which refresh it outputs.

yes, but it seems that although the game adjusts the vsync to 50hz, the core continues to output 50.4hz and that small deviation is what seems to produce stuttering. On previous page have been published videos with details. C64 core had the same problem but video sync adjustments were made and now it works butter smooth.

[paulbnl]

in addition do you think would be possible to set the vertical frequency for pal mode to a value closer to the 50hz standard for smoother scrolls in some tv's and scalers?

Thanks

video mode on Amiga is programmable and it depends on specific game/app which refresh it outputs.

The core clock is faster than original. Original frequencies are PAL: 28.37516MHz and NTSC: 28.63636 MHz.

https://eab.abime.net/showpost.php?p=681754&postcount=2

[Sorgelig]

in addition do you think would be possible to set the vertical frequency for pal mode to a value closer to the 50hz standard for smoother scrolls in some tv's and scalers?

Thanks

video mode on Amiga is programmable and it depends on specific game/app which refresh it outputs.

The core clock is faster than original. Original frequencies are PAL: 28.37516MHz and NTSC: 28.63636 MHz.

https://eab.abime.net/showpost.php?p=681754&postcount=2

Well, the base for Minimig is NTSC which probably is better to change to PAL base as 99% games and demos are PAL.
Probably PLL reconfig can be added for NTSC/PAL clocks, but core is pretty much unstable itself, so i don't want to add more instability.

[retrorepair]

Does anyone know where in the code a valid step pulse exists? I'm starting to think one doesn't exist.

Do you mean something derived from 50/60Hz on the mains? Nope, the PSU feeds only DC to the A500.

Sorry no I mean the signal sent to the floppy disk to increment the head. All of the signals I've found are 30-100us and a step pulse needs to be 1ms minimum.

I'm probably missing something but I wondernif it's fudged as no one ever expected a floppy drive to be connected.

I should add I'm not intending to connect a floppy drive to try and read/write a disk, I just want to send motor signals over USER_IO for audible effect.

The other signals seem usable, just step doesn't look right.

*EDIT* Seems like I have to construct my own step pulse, should be fun

I've been trying to work this out for a while and I fear it may be beyond my capability. The _step pulse that minimig generates is only 20us. It should be at least 3ms, any ideas why?

[retrorepair]

So I made sure the assignments to the IO were made on the rising edge of the clock and now all the floppy signals look exactly like they do on my real Amiga on the logic analyzer.

Still no stepping though. Do these drives need to have 5v logic? The SNAC only seems to be able to manage 4.9v but I'd have thought this would be enough?

I can't think why else this isn't stepping, the step, select, motor and direction signal waveforms look identical and are within .2us of the real amiga. Surely close enough?

[LamerDeluxe]

I'd love to have a buzzer (or haptic solenoid like in modern phones) on the MiSTer simulating the sounds of the Amiga drive, that is really missing from the experience.

[retrorepair]

I'd love to have a buzzer (or haptic solenoid like in modern phones) on the MiSTer simulating the sounds of the Amiga drive, that is really missing from the experience.

A buzzer IO board is planned, I just need to work out the best way to implement it. I'd like something a bit more authentic but for now I'd say a buzzer is quite likely.

I ended up working out the issue, it was the logic levels that the drive didn't like. I actually ended up using an arduino with direct port control (digitalRead is way too slow) to fake a level shifter which worked surprisingly well. Apparently manipulating the ports this way can get down to ns timing.

Here's a video of Hybris loading on MISTer hooked up to a real Amiga floppy drive. Keep in mind this is loading from SD, the floppy drive is simply using the control signals in minimig to appear as if it's loading. I'm very pleased, it's great to hear that feedback again

https://youtu.be/sbQoD0qKI4M

[BBond007]

I've been trying to work this out for a while and I fear it may be beyond my capability. The _step pulse that minimig generates is only 20us. It should be at least 3ms, any ideas why?

I hope you can work it out...

The Minimig 1.1 supports this feature, and I do think it is sounds more authentic than WinUAE floppy sounds blasting from my amplified stereo speakers.

On my Minimig 1.1 I put tape over the buzzer port to make the sound softer.

I would mount the buzzer in the floppy area on my A1200 MiSTer --> http://www.atari-forum.com/viewtopic.ph ... 75#p375012

Thanks!

[ericgus]

It would be nice to have the floppy sounds.. there is something sigularly unique about the amigas disk drive sounds, the "tick tick tick" when looking for a disk, the loading noises, has lots of "feels" and memories associated with it, I even fitted my FlashFloppy Gotek drives with the piezo sound mod to get that effect.. Thank you for persisting and making this likely to happen..

[retrorepair]

I've been trying to work this out for a while and I fear it may be beyond my capability. The _step pulse that minimig generates is only 20us. It should be at least 3ms, any ideas why?

I hope you can work it out...

The Minimig 1.1 supports this feature, and I do think it is sounds more authentic than WinUAE floppy sounds blasting from my amplified stereo speakers.

On my Minimig 1.1 I put tape over the buzzer port to make the sound softer.

I would mount the buzzer in the floppy area on my A1200 MiSTer --> http://www.atari-forum.com/viewtopic.ph ... 75#p375012

Thanks!

Did you see the video I posted? You would have space in your replica case for an actual floppy drive, I plan the do the same thing

[LamerDeluxe]

I'd love to have a buzzer (or haptic solenoid like in modern phones) on the MiSTer simulating the sounds of the Amiga drive, that is really missing from the experience.

A buzzer IO board is planned, I just need to work out the best way to implement it. I'd like something a bit more authentic but for now I'd say a buzzer is quite likely.

I ended up working out the issue, it was the logic levels that the drive didn't like. I actually ended up using an arduino with direct port control (digitalRead is way too slow) to fake a level shifter which worked surprisingly well. Apparently manipulating the ports this way can get down to ns timing.

Here's a video of Hybris loading on MISTer hooked up to a real Amiga floppy drive. Keep in mind this is loading from SD, the floppy drive is simply using the control signals in minimig to appear as if it's loading. I'm very pleased, it's great to hear that feedback again

https://youtu.be/sbQoD0qKI4M

The more authentic sounding the better, I agree. That why I was thinking about a haptic vibration motor, but I'm not sure that would be loud enough if it didn't hit something and you'd need a suitable MiSTer housing to amplify the sound.

Great work on figuring out the stepper motor signals. I'm glad someone is working on this.

Hybris is exactly the game I was thinking about. It is my favorite Amiga game and it has very distinct loading noises. The sounds in the video are very accurate. I love how the drive is much larger than the MiSTer.

[breiztiger]

hi

https://www.pouet.net/prod.php?which=3073

crash after some time at final scrolling

config : 68000 OCS-500 512ko CHIP + 2Mo FAST KS 1.3

edit : A500 config with 512 slow + 512 chip work in winuae but on mister the demo say "I CAN NOT FIND YOUR EXTRA MEMORY"

[amontre]

Hello, new minimig user here. Anyone here use minimig with 15khz arcade monitor ? I'm trying figure out how to adjust the horizontal position for the whdload games. I got full screen on workbench (NTSC Hi-Res) but when I load the games there's a gap on left of the screen.

[Chris23235]

Most Amiga games aren't designed for NTSC.

[ericgus]

Most Amiga games aren't designed for NTSC.

All the older original ones are .. Defender of the Crown, Test Drive, and many of the classics are too .. etc.. so I guess its your perspective that dictates the answer.. as I live in NTSC land, most of the games I care about/play ARE designed for NTSC, were created on NTSC machines to be played on NTSC machines..

[BBond007]

Hello, new minimig user here. Anyone here use minimig with 15khz arcade monitor ? I'm trying figure out how to adjust the horizontal position for the whdload games. I got full screen on workbench (NTSC Hi-Res) but when I load the games there's a gap on left of the screen.

It really depends on the game... Sometimes the screen needs to be positioned further to the right in order to have enough DMA to use sprite #6 and #7.