Idea for a compact Amiga 1200 RTG card with a passthrough for an accelerator card

markpaterson · 17 January 2022, 19:29

Would it be possible to create a compact FPGA based RTG card that fit into the accelerator slot and had a passthrough slot for your accelerator?

The Mediator PCI hardware has an accelerator passthrough, so at least in theory my idea could work on a similar principle. The difference with my idea is that everything remains inside the original Amiga 1200 case.

Most modern Amiga accelerators are very small compared to the longer cards we had back in the day. It got me thinking that there's a LOT of space next to the card that could be exploited with some minor modifications to the case on the inside – possibly just cutting away the plastic rail below the motherboard barcode (see pic below). Even with a traditional Blizzard 1230 IV sized accelerator, there's space to the right of the board that the accelerator could be moved over into – the board just wouldn't be accessible via the trapdoor slot anymore.

An RTG Amiga is still very desirable to have in 2022, and as an A1200 user I've always felt pretty shut out from that world. I know there are options like Vampire, but that involves basically a full FPGA lobotomy and I don't want to go down that road, and I don't want to tower my Amiga with a Mediator because I love the wedge form factor.

This hypothetical FPGA RTG card would have HDMI or micro HDMI on board. Perhaps there could even be room for a built in scandoubler that takes an input from the native RGB and outputs it through the HDMI – this could be as basic as a DB23 cable from the external RGB port, then the cable is passed back into the Amiga, connecting to the RTG board via VGA or mini VGA.

As you can see from the pics below, I have a Gotek drive too, but I run it with the enclosure opened up. Moving the accelerator over a few inches would not be obstructed by the Gotek circuit board but it could possibly require cutting into the Gotek enclosure itself.

For example, this is how my Amiga looks with the ACA1221.

This is my mockup with a hypothetical compact FPGA RTG Graphics Card.

I have no expertise or experience creating hardware. This is simply an idea I had. I know that people from the Amiga hardware scene frequent this board so I would like to hear you thoughts on if you think this is feasible.

grond · 17 January 2022, 19:33

Even though the ACA1221 is rather small, it does nontheless collide with the case in your example image.

markpaterson · 17 January 2022, 19:46

It does, but like I said it would require some modification to the case internally. Nothing 5 minutes with a Dremel wouldn't solve haha. Externally it would look exactly as original.

grond · 17 January 2022, 19:50

Case modifications are evil. In any case there are A1200 accelerators with additional graphics card functionality, hence, it would be possible to do it.

cugar124 · 17 January 2022, 19:56

The warp 1260 has rtg the vampire and the blizzard PPC too you would need a new accelerator card maybe 030 or full FPGA to get it to fit buddy.

Sent from my Pixel 4a (5G) using Tapatalk

markpaterson · 17 January 2022, 19:58

Quote:

Originally Posted by grond

Case modifications are evil. In any case there are A1200 accelerators with additional graphics card functionality, hence, it would be possible to do it.

Yeah you're definitely at risk of invalidating your Commodore warranty!

idrougge · 17 January 2022, 20:32

Well, considering that you probably will want both a certain amount of memory to hold 24-bit bitmaps and a certain amount of CPU performance to handle those 24-bit bitmaps, you will probably not be satisfied by a simple 020 card (not to mention that those based on an EC020 don’t have the prerequisite address space), in which case you might just as well go for a Warp 1260 to begin with.

alexh · 17 January 2022, 20:46

The PiStorm32 for the A1200 will be a high end RTG card and a super fast NVMe PCIe SSD HDD, a 680x0 accelerator faster than any A1200 accelerator to date, 128 MB RAM, WiFi card, ethernet, SPI and should be here in 2022 and be around £150

Jpor · 17 January 2022, 22:06

Quote:

Originally Posted by alexh

The PiStorm32 for the A1200 will be a high end RTG card and a super fast NVMe PCIe SSD HDD, a 680x0 accelerator faster than any A1200 accelerator to date, 128 MB RAM, WiFi card, ethernet, SPI and should be here in 2022 and be around £150

This looks nice!

Bruce Abbott · 18 January 2022, 08:34

Quote:

Originally Posted by idrougge

Well, considering that you probably will want both a certain amount of memory to hold 24-bit bitmaps and a certain amount of CPU performance to handle those 24-bit bitmaps, you will probably not be satisfied by a simple 020 card (not to mention that those based on an EC020 don’t have the prerequisite address space), [in which case you might just as well go for a Warp 1260 to begin with.

500 Euro + your own 68060. You're joking, right?

The real problem is that the accelerator card thinks it is looking at the A1200 motherboard, so it will slow down to motherboard bus speed when accessing the RTG memory - which must be inside the 24 bit address space whether the CPU is an EC020 or full 32 bit.

A more interesting question is could a Blizzard 1230 IV take an RTG card on its expansion connector, rather than the SCSI/RAM board that was made for it?

Quote:

Originally Posted by alexh

The PiStorm32 for the A1200 will be a high end RTG card and a super fast NVMe PCIe SSD HDD, a 680x0 accelerator faster than any A1200 accelerator to date, 128 MB RAM, WiFi card, ethernet, SPI and should be here in 2022 and be around £150

I'll believe it when I see it.

Daedalus · 18 January 2022, 09:46

If you're designing a new accelerator card to suit this hypothetical new RTG card, there's no reason to be limited to 24-bit addressing, or motherboard bus speeds for that matter. The A1200 CPU slot has all 32 address bits allocated - it just doesn't connect the top 8 at the motherboard.

NovaCoder · 18 January 2022, 10:08

Quote:

Originally Posted by alexh

The PiStorm32 for the A1200 will be a high end RTG card and a super fast NVMe PCIe SSD HDD, a 680x0 accelerator faster than any A1200 accelerator to date, 128 MB RAM, WiFi card, ethernet, SPI and should be here in 2022 and be around £150

Looking good

alexh · 18 January 2022, 10:28

Quote:

Originally Posted by Bruce Abbott

Quote:

Originally Posted by alexh

The PiStorm32 for the A1200 will be a high end RTG card and a super fast NVMe PCIe SSD HDD, a 680x0 accelerator faster than any A1200 accelerator to date, 128 MB RAM, WiFi card, ethernet, SPI and should be here in 2022 and be around £150

I'll believe it when I see it.

PiSTorm for 16-bit Amiga's has been around for about 2 years. It costs approx £40. It has almost everything that PiSTorm32 has, RAM, Wifi, RTG, AHI, USB, SPI (everything except the NVMe drive). It is the fastest 680x0 accelerator you can buy. It's still in development, doesn't have 100% compatibility (mainly due to slower than normal ChipRAM access). It is open source with multiple developers so is getting improved compatibility and new features all the time (AHI sound with passthrough was recently added).

The PiSTorm32 PCB design is now proven. Besides the PCB physical form factor the main difference between PiSTorm and PiSTorm32 is the bus bridge (16-bit vs 32-bit) which is IIUC completely different design. There is very little reason this can't be here before end of 2022.

Jpor · 18 January 2022, 19:03

Quote:

Originally Posted by Bruce Abbott

A more interesting question is could a Blizzard 1230 IV take an RTG card on its expansion connector, rather than the SCSI/RAM board that was made for it?

I seriously doubt it. If it has any type of firmware built into the card, my guess is it’s primary purpose is to look for a SCSI card. If it’s anything like the 603e cards where you can either plug in a RTG card (BVision) or a PCI add on board (G-Rex), then the firmware would have to be changed.

Matt_H · 18 January 2022, 19:51

Quote:

Originally Posted by Jpor

I seriously doubt it. If it has any type of firmware built into the card, my guess is it’s primary purpose is to look for a SCSI card. If it’s anything like the 603e cards where you can either plug in a RTG card (BVision) or a PCI add on board (G-Rex), then the firmware would have to be changed.

The slot on the 1230IV/1260 is capable of more than SCSI. Phase 5 surveyed their users as to what kind of expansions they wanted to see for the connector, but only the SCSI board was ever built.

Daedalus · 19 January 2022, 00:27

Bear in mind that the SCSI expansion also included an additional RAM slot and a boot ROM. The expansion connector looks to include pretty much the whole CPU bus, and as such could likely be used for anything so long as software was coded for it.

Jpor · 19 January 2022, 02:16

Quote:

Originally Posted by Matt_H

The slot on the 1230IV/1260 is capable of more than SCSI. Phase 5 surveyed their users as to what kind of expansions they wanted to see for the connector, but only the SCSI board was ever built.

Good to know

Matt_H · 19 January 2022, 02:37

Quote:

Originally Posted by Jpor

Quote:

Originally Posted by Matt_H

The slot on the 1230IV/1260 is capable of more than SCSI. Phase 5 surveyed their users as to what kind of expansions they wanted to see for the connector, but only the SCSI board was ever built.

Good to know

Actually, I need to correct myself - I can't find proof of the aforementioned survey. But the 1260 manual describes the slot as a DMA bus for "e.g." the SCSI module, so with that plus Daedalus's technical overview I think it's still safe to say that something else could attach to it.

Bruce Abbott · 19 January 2022, 08:03

Quote:

Originally Posted by Daedalus

If you're designing a new accelerator card to suit this hypothetical new RTG card, there's no reason to be limited to 24-bit addressing, or motherboard bus speeds for that matter. The A1200 CPU slot has all 32 address bits allocated - it just doesn't connect the top 8 at the motherboard.

If you are designing a new accelerator card then this 'passthrough' method of providing RTG is an awkward way to do it. If used alone or with an existing accelerator card it is limited to 24 bit.

alexh · 19 January 2022, 10:27

Quote:

Originally Posted by Bruce Abbott

then this 'passthrough' method of providing RTG is an awkward way to do it. If used alone or with an existing accelerator card it is limited to 24 bit.

Bruce means 24-bit address not colour. Just in case anyone wasn't sure.

17 January 2022, 19:29	#1
markpaterson Registered User Join Date: Jan 2016 Location: Bay Area / USA Posts: 43	Idea for a compact Amiga 1200 RTG card with a passthrough for an accelerator card Would it be possible to create a compact FPGA based RTG card that fit into the accelerator slot and had a passthrough slot for your accelerator? The Mediator PCI hardware has an accelerator passthrough, so at least in theory my idea could work on a similar principle. The difference with my idea is that everything remains inside the original Amiga 1200 case. Most modern Amiga accelerators are very small compared to the longer cards we had back in the day. It got me thinking that there's a LOT of space next to the card that could be exploited with some minor modifications to the case on the inside – possibly just cutting away the plastic rail below the motherboard barcode (see pic below). Even with a traditional Blizzard 1230 IV sized accelerator, there's space to the right of the board that the accelerator could be moved over into – the board just wouldn't be accessible via the trapdoor slot anymore. An RTG Amiga is still very desirable to have in 2022, and as an A1200 user I've always felt pretty shut out from that world. I know there are options like Vampire, but that involves basically a full FPGA lobotomy and I don't want to go down that road, and I don't want to tower my Amiga with a Mediator because I love the wedge form factor. This hypothetical FPGA RTG card would have HDMI or micro HDMI on board. Perhaps there could even be room for a built in scandoubler that takes an input from the native RGB and outputs it through the HDMI – this could be as basic as a DB23 cable from the external RGB port, then the cable is passed back into the Amiga, connecting to the RTG board via VGA or mini VGA. As you can see from the pics below, I have a Gotek drive too, but I run it with the enclosure opened up. Moving the accelerator over a few inches would not be obstructed by the Gotek circuit board but it could possibly require cutting into the Gotek enclosure itself. For example, this is how my Amiga looks with the ACA1221. This is my mockup with a hypothetical compact FPGA RTG Graphics Card. I have no expertise or experience creating hardware. This is simply an idea I had. I know that people from the Amiga hardware scene frequent this board so I would like to hear you thoughts on if you think this is feasible. Last edited by markpaterson; 17 January 2022 at 19:35.

17 January 2022, 20:46	#8
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,332	The PiStorm32 for the A1200 will be a high end RTG card and a super fast NVMe PCIe SSD HDD, a 680x0 accelerator faster than any A1200 accelerator to date, 128 MB RAM, WiFi card, ethernet, SPI and should be here in 2022 and be around £150 Attached Thumbnails Last edited by alexh; 17 January 2022 at 20:54.

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17 January 2022, 19:33	#2
grond Registered User Join Date: Jun 2015 Location: Germany Posts: 1,918	Even though the ACA1221 is rather small, it does nontheless collide with the case in your example image.

17 January 2022, 19:46	#3
markpaterson Registered User Join Date: Jan 2016 Location: Bay Area / USA Posts: 43	It does, but like I said it would require some modification to the case internally. Nothing 5 minutes with a Dremel wouldn't solve haha. Externally it would look exactly as original.

17 January 2022, 19:50	#4
grond Registered User Join Date: Jun 2015 Location: Germany Posts: 1,918	Case modifications are evil. In any case there are A1200 accelerators with additional graphics card functionality, hence, it would be possible to do it.

17 January 2022, 19:56	#5
cugar124 Registered User Join Date: Jun 2012 Location: Belfast Posts: 82	The warp 1260 has rtg the vampire and the blizzard PPC too you would need a new accelerator card maybe 030 or full FPGA to get it to fit buddy. Sent from my Pixel 4a (5G) using Tapatalk

17 January 2022, 20:32	#7
idrougge Registered User Join Date: Sep 2007 Location: Stockholm Posts: 4,332	Well, considering that you probably will want both a certain amount of memory to hold 24-bit bitmaps and a certain amount of CPU performance to handle those 24-bit bitmaps, you will probably not be satisfied by a simple 020 card (not to mention that those based on an EC020 don’t have the prerequisite address space), in which case you might just as well go for a Warp 1260 to begin with.

18 January 2022, 09:46	#11
Daedalus Registered User Join Date: Jun 2009 Location: Dublin, then Glasgow Posts: 6,334	If you're designing a new accelerator card to suit this hypothetical new RTG card, there's no reason to be limited to 24-bit addressing, or motherboard bus speeds for that matter. The A1200 CPU slot has all 32 address bits allocated - it just doesn't connect the top 8 at the motherboard.

19 January 2022, 00:27	#16
Daedalus Registered User Join Date: Jun 2009 Location: Dublin, then Glasgow Posts: 6,334	Bear in mind that the SCSI expansion also included an additional RAM slot and a boot ROM. The expansion connector looks to include pretty much the whole CPU bus, and as such could likely be used for anything so long as software was coded for it.

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