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23

That expansion port exposes all the signals from the 68000 CPU, plus some other Amiga specific signals, such as the color CLK, ROM and RAM select signals, along with voltage supply lines, etc. It is documented in the schematic, page F-9 of the User's Manual. It worked by removing its trap door, and plugging in a compatible device with the Amiga switched off....


21

The [pre-AGA] Amiga: uses a planar frame buffer, stored in memory that is shared with the CPU (and which therefore reduces the CPU's speed); provides dual-playfield hardware scrolling, but the total bit fetch total per output byte doesn't stretch beyond six, so you end up with e.g. a 7 colour foreground and an eight colour background; provides 8 hardware ...


16

Alright, you seem to already have the correct keymap file in DEVS:keymaps/, as you seem to be able to use the Keymap in Workbench programs. That's good (otherwise you would have had to copy it from "Extras 1.3:Devs/keymaps" to DEVS:keymaps/). Now open your Workbench disk and start the Shell. In the Shell, type: ed S:Startup-Sequence This will bring up a ...


14

They did, with the A600. But in true late-stage Commodore fashion, they screwed it up and made it more expensive. To cost-reduce an A500, you'd have to reproduce its spec on simpler silicon. The market wasn't interested in an 8 MHz 68000 in 1991/92: the PC had stolen all of the Amiga's thunder at commodity prices. The Amiga's niche silicon was just too ...


12

'Jeff Porter realized it would not be possible to significantly cost reduce the Amiga 500 to get it into the $250 retail price range'. They could have cost-reduced the A500 - perhaps even to $250 retail - but they would have had to make some compromises that (thankfully) they weren't willing to do. There were a lot of chips on the board. They needed ...


10

A stock Amiga 500 doesn't come with any expansion port that would take a standard CD ROM drive (or hard disk) directly. Storage extension is limited to external floppy drives. The option of the day was to obtain an A570 1, a rather bulky interface that fitted to the A500 expansion port, which contained quite a bit of circuitry (DMA, ROMs containing the new ...


9

No, you can and, more importantly, it is fully supported to run Workbench 1.3 on a Kickstart 1.2 machine. This was rather common back at that time, because Workbench 1.3 brought some nice new features (like the RAD: drive, better printer drivers), and at least in Europe the first batches of Amiga 500 and Amiga 2000 arrived still with Kickstart 1.2. On ...


7

It is hard to find authoritative information about the differences between the various A500 PCB revisions but aside from what is already signalled in the Big Book of Amiga Hardware they essentially differ by the position and types of the jumpers which control how the expansion memory can be used. These jumpers serve to specify whether the expansion memory ...


7

Your first choice is to see if with a little modification, the A520 box can be used as a NTSC encoder. Open it, locate chip MC1377, take pin 20 (which will be unconnected) and ground it. That will make the chip to act as a NTSC encoder. I don't know if this will be enough, as there seems to be some resonant circuits all over the board, that may be tuned to ...


6

It is possible that the old lubrication on the sticking part has absorbed some fluff or grit and so is no longer working as a lubricant. The build-up of muck could be around the point where the arm latches. Your screwdriver trick could be freeing it enough to work for a while. I would clean the part as much as possible. Use a residue-free solvent - I ...


6

Multiple sources on the internet point out that Rev 8a is indeed an Amiga 500 Plus and not a regular Amiga 500. And your picture clearly shows A500+ printed on the board. So I guess it can be said you own an A500 Plus, just with a 2MB Agnus but 512KB of memory. Does it have an on board clock chip and battery, out of curiosity? The A500Plus service manual (...


4

TL;DR: For all of this it might be helpful and take a step back from bits and bytes and take a step back to look at the whole process of Game development. Doing so will show that quality is much more dependant on the budget available than the hardware to be used. Budget can buy time to create quality and pay for creativity. The market for Mega Drive games ...


4

I managed to fix the floppy disk drive mechanism. I completly disassemblied the floppy disk drive mechanical system and cleaned each part with lighter fluid. Then I applied a very light lubrication to the areas where the parts where in contact with one another. Only a really small amount of lubricant is needed (I used an unfolded paperclip to apply it). I ...


4

When you switch on an Amiga, you should expect to see the following: The power light will illuminate, slightly dimmed. About half a second later, the power light will brighten. Usually 3-4 seconds later (but could be up to a minute for Amiga models with HD controllers), the floppy drive will start to make noises. For this check to work, you need only plug ...


4

The Megadrive comes from an arcade machine lineage, it's cut-down Sega arcade machine hardware. The Amiga comes from a computer lineage, it's an evolution of the Atari 800, same designer, and many of the same features, just expanded. Particularly, the Amiga, like most computers, deals with pixels. Better for things like line drawing, proportional text, and ...


3

Let's assume your assumption "MegaDrive games are generally 'better' than Amiga games" was true - Which is a statement hard to prove and very probaby only backed by opinion: Games Console vs. Home Computer - Marketing goals The main (rather: only) selling point for consoles is the quality of games available for the platform. There is absolutely no other ...


3

Any memory card added to the expansion bay will only show up as slow RAM, by default. To increase the amount of chip RAM you would need to make modifications. To get more than 512KB of chip RAM you need to add the missing RAM to the motherboard, and to get more than 1MB of chip RAM you also need to add the missing 74F(AS)139 at the unpopulated U32 location ...


3

I think it really depends on what type of use you want out of your Amiga. If sharp text and sharp Workbench are important, then a high quality scan-doubler is going to be the best option...but, expensive. I tried the GBS-8220 everyone raves about and I really don't see how people can use that thing. Maybe I got a bad one. But in my experience, the image ...


2

You need to have a 8372A Fatter Agnus chip, and have to modify the mainboard to enable the 1mb chip ram mode. I am not really familiar with the A500+, but you can do a search to find out what needs to be done. On an A500 with a ver 5 mainboard, you need to modify JP2 by cutting the trace between the two bottom pads, and join the top and center pads with a ...


2

In short, the Amiga 500 expansion port was an exact electrical equivalent of the expansion port of Amiga 1000, and very similar to the Zorro II card slots of the Amiga 2000 and above. The Zorro II card slots of the Amiga 2000 and greater models had 14 extra pins compared to the Amiga 500/1000 expansion port. See: http://www.ntrautanen.fi/computers/hardware/...


2

In addition to mcleod_ideafix' answer above: Commodore also made a CD-ROM drive that plugged in the slot (unfortunately without a feed-through slot on the other side): the A570 turned the Amiga 500 into a CDTV. Unfortunately, the A570 was released after the A500 was discontinued and replaced with the A600, it had a caddy (not a tray) and it ran at single-...


1

This is what I think is the right answer. Anyway, I would like to have some feedback before selecting it as the right answer. After looking at the schematics I think these are the possible cases and outcomes: If I add the a501+ (1MB) to the A500 rev8 (0.5MB without U32) then: _BCASL0 = _BCASL1 _BCASH0 = _BCASH1 Therefore internal and external banks ...


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