Looks like I'll be getting a Mega ST4 soon

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rubber_jonnie
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Re: Looks like I'll be getting a Mega ST4 soon

Post by rubber_jonnie » Fri May 22, 2020 9:44 pm

I'm sure some of you will cringe seeing this thread pop up again, but no, the Mega4 still lives and just got a minor upgrade :)

My erasable 27C4096s arrived and after a run through the eraser, I tested them all with my first effort at a dual ROM, and have dropped one into my Mega 4, specifically in the V1.1C IDE board.

I can now boot from IDE in either TOS 1.04 or TOS 2.06, and I'm really pretty stoked at the success of my first go at a dual ROM. All I need now is to find a switch so I can switch between them and it's actually complete!!

In time I will get some OTP ROMs, as the erasable ones are way too useful to leave in a machine :)

:girldance: :girldance: :girldance:
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
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Tomswork
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Re: Looks like I'll be getting a Mega ST4 soon

Post by Tomswork » Fri May 22, 2020 9:48 pm

Excellent

Tom

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PhilC
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Re: Looks like I'll be getting a Mega ST4 soon

Post by PhilC » Fri May 22, 2020 10:31 pm

Just be careful with the pins on those eprom. They don't have the usual grooves in the base of the chip that helps to keep them in the right place.
If it ain't broke, test it to Destruction.

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Re: Looks like I'll be getting a Mega ST4 soon

Post by rubber_jonnie » Fri May 22, 2020 11:35 pm

PhilC wrote:
Fri May 22, 2020 10:31 pm
Just be careful with the pins on those eprom. They don't have the usual grooves in the base of the chip that helps to keep them in the right place.
Yes, I'd noticed, and one needed a little tweak!
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

Tomswork
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Re: Looks like I'll be getting a Mega ST4 soon

Post by Tomswork » Sat May 23, 2020 12:16 am

Screenshot_20200522-134348_eBay.jpg
Screenshot_20200522-134348_eBay.jpg (105.15 KiB) Viewed 148 times
I got this adapter works great for 27c4096 but pin 2 is fickle with my tl866

Tom

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Re: Looks like I'll be getting a Mega ST4 soon

Post by rubber_jonnie » Sat May 23, 2020 9:11 am

Tomswork wrote:
Sat May 23, 2020 12:16 am

I got this adapter works great for 27c4096 but pin 2 is fickle with my tl866

Tom
My TL866 came with about 5 adapters, but the PLCC 44 one didn't work initially and I had to fix it as 2 pins weren't actually connected that should have been.
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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derkom
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Re: Looks like I'll be getting a Mega ST4 soon

Post by derkom » Sat May 23, 2020 9:28 am

rubber_jonnie wrote:
Sat May 23, 2020 9:11 am
My TL866 came with about 5 adapters, but the PLCC 44 one didn't work initially and I had to fix it as 2 pins weren't actually connected that should have been.
They're connected correctly, but for PLCC44 programmable microcontrollers, not for PROMs.

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Re: Looks like I'll be getting a Mega ST4 soon

Post by rubber_jonnie » Sat May 23, 2020 9:31 am

derkom wrote:
Sat May 23, 2020 9:28 am
rubber_jonnie wrote:
Sat May 23, 2020 9:11 am
My TL866 came with about 5 adapters, but the PLCC 44 one didn't work initially and I had to fix it as 2 pins weren't actually connected that should have been.
They're connected correctly, but for PLCC44 programmable microcontrollers, not for PROMs.
Ahhh, that would make sense.
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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Re: Looks like I'll be getting a Mega ST4 soon

Post by rubber_jonnie » Sun May 31, 2020 4:51 pm

I've been toying with the idea of adding a front panel switch to my Mega4 since installing @exxos IDE v1.1C adaptor.

Since I got my erasable 27C4096 ROMs, I'd made my first dual boot image with TOS 1.04(IDE patched)/TOS 2.06 and was pretty happy with the results, but today I decided to go one further and created an image with EmuTOS 0.9.12 and TOS 2.06.

As per usual once I'd created the ROM in HxD and saved the image, I then used Cartman to byteswap the image since this is necessary to work with my TL866II+. I've attached both the standard and byteswapped (Marked _BS) images for anybody that wants them, since EmuTOS is open source and TOS 2.06 is freely available.

Here is the new switch (I won't bore you with how to install it, it's 3 wires!), I need to do neater labelling, but it's good for now:

Mega_Front.jpg
Mega_Front.jpg (71.86 KiB) Viewed 23 times

And before I have a bunch of comments about 'How could I cut my Mega4 case like that?', that was how it arrived when I bought it. I'm highly likely to paint the Gotek mount a matching grey at some time in the near future so it looks a bit nicer.

Booting to EmuTOS:

EMU_Boot.jpg
EMU_Boot.jpg (92.92 KiB) Viewed 23 times

And finally at the EmuTOS desktop:

EMU_Desk.jpg
EMU_Desk.jpg (134.81 KiB) Viewed 23 times

Of course this doesn't need to be a final configuration, a ROM swap and label change is all I need for some other config. I'll get some proper OTP ROMs soon too, as the erasable ROMs have quite a poor design and it's easy for the pins to get knocked out of kilter.

Interestingly, @terriblefire had mentioned about EmuTOS not needing the connection to the ACSI IRQ line that is needed for TOS 2.06 and IDE. I deliberately disconnected the IRQ line and EmuTOS boots 100% with no problem from IDE without the IRQ line present. It also used it's own internal IDE driver and there was no sign of HDDRIVER loading during boot.

Also, running XFRRATE.TTP under EmuTOS gave a fastest (RWABS) result of 1120kb/s, whereas under TOS 2.06 with HDDRIVER with Blitter acceleration the fastest result was 1540kb/s (RWABS). I know that even with Blitter acceleration disabled HDDRIVER comes in just over the 1300kb/s mark, so EmuTOS clearly doesn't have quite the performance levels under IDE.
Attachments
Emutos_206_BS.img.txt
(512 KiB) Not downloaded yet
Emutos_206.img.txt
(512 KiB) Not downloaded yet
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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PhilC
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Re: Looks like I'll be getting a Mega ST4 soon

Post by PhilC » Sun May 31, 2020 7:08 pm

@rubber_jonnie thanks for sharing the tos files, you've beat me to it so I shall borrow yours instead of making my own :D
If it ain't broke, test it to Destruction.

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