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I have found on a few site the mention that the Colecovision and the SG1000 share very similar hardware to point that the SG-1000 may be cloned from it.
I am trying to find out if this is true and was wondering if anyone had in evidence of this, if there is a thread on this topic already please point me there but I couldn't seem to find it.

Here's what I have found so far.

- A few websites claim Sega was going to distribute the Colecovision in japan in 1982 a year before the SG-1000 was released but I cant find any documented proof of this.

- Both systems share a lot of the same chips but this could be due to the fact that they were easy to come by.

- Games came be ported relatively easily between both platforms

All input welcome

PkK is the man to ask for more details but basically - yes, same processor, same VDP, same PSG chip, same amount of VRAM and RAM if I'm not mistaken.

While I have some knowledge of the technical details of both consoles (and written a framework that allows to write games targeting both, and compile it into a ROM for each), I am not that familiar with history.

I've read claims that Sega started developing the SC-3000 first, and then derived the SG-1000 from it (the reference given is an article in Retro Gamer, No. 163, but I haven't checked it). This could indicate that the SG-1000 was not derived from the ColecoVision.
I've also read the opposite, but without references given.
In the end, both the SC-3000 and SG-1000 were released simultaneously.

The components used were indeed standard stuff back then (and already in use in some microcomputers, such as the TI-99/4, which made development and finding experienced developers familiar with the hardware easier).
So a console designed by looking at the easily available components, when done by someone familiar with the microcomputers of the time is likely to end up with the set of components the ColecoVision and SG-1000 have.
On the other hand, the joystick ports would not be present in a microcomputer of the time, so the consoles had to come up with their own solutions. And indeed the joystick ports of the ColecoVision and the SG-1000 are quite different (though both use discrete logic chips from the 74LS series, which back then was the standard for logic where speed doesn't matter much).

So, IMO the technical similarities do not point to the SG-1000 being derived from the ColecoVision.

It seems, I can't help much with this question.

P.S.: Another aspect that would not be derived from microcomputers would be the cartridge port. And again, here we see differences between the ColecoVision and the SG-1000.

This may be a silly question but the two systems seem to be able to play each others games (with little modifications) is this because they use the same chips or because they use the same chips that have been placed in the same layout?

I hope that question makes sense.

It's because they use the same chips. In a software sense they don't have the same layout, you have to change things around for it to work. Similarly MSX has the same CPU and video chip, and RAM and ROM is pretty universally used.

Author	Message
BIG D Joined: 09 Jan 2018 Posts: 228 Location: Melbourne, Australia	Colecovision - SG-1000 connection Posted: Wed Jun 12, 2019 8:17 am
	I have found on a few site the mention that the Colecovision and the SG1000 share very similar hardware to point that the SG-1000 may be cloned from it. I am trying to find out if this is true and was wondering if anyone had in evidence of this, if there is a thread on this topic already please point me there but I couldn't seem to find it. Here's what I have found so far. - A few websites claim Sega was going to distribute the Colecovision in japan in 1982 a year before the SG-1000 was released but I cant find any documented proof of this. - Both systems share a lot of the same chips but this could be due to the fact that they were easy to come by. - Games came be ported relatively easily between both platforms All input welcome

sverx Joined: 05 Sep 2013 Posts: 3827 Location: Stockholm, Sweden	Posted: Wed Jun 12, 2019 10:00 am
	PkK is the man to ask for more details but basically - yes, same processor, same VDP, same PSG chip, same amount of VRAM and RAM if I'm not mistaken.

PkK Joined: 07 Aug 2007 Posts: 220 Location: Yach, Germany	Posted: Wed Jun 12, 2019 11:12 am
	While I have some knowledge of the technical details of both consoles (and written a framework that allows to write games targeting both, and compile it into a ROM for each), I am not that familiar with history. I've read claims that Sega started developing the SC-3000 first, and then derived the SG-1000 from it (the reference given is an article in Retro Gamer, No. 163, but I haven't checked it). This could indicate that the SG-1000 was not derived from the ColecoVision. I've also read the opposite, but without references given. In the end, both the SC-3000 and SG-1000 were released simultaneously. The components used were indeed standard stuff back then (and already in use in some microcomputers, such as the TI-99/4, which made development and finding experienced developers familiar with the hardware easier). So a console designed by looking at the easily available components, when done by someone familiar with the microcomputers of the time is likely to end up with the set of components the ColecoVision and SG-1000 have. On the other hand, the joystick ports would not be present in a microcomputer of the time, so the consoles had to come up with their own solutions. And indeed the joystick ports of the ColecoVision and the SG-1000 are quite different (though both use discrete logic chips from the 74LS series, which back then was the standard for logic where speed doesn't matter much). So, IMO the technical similarities do not point to the SG-1000 being derived from the ColecoVision. It seems, I can't help much with this question. P.S.: Another aspect that would not be derived from microcomputers would be the cartridge port. And again, here we see differences between the ColecoVision and the SG-1000.

BIG D Joined: 09 Jan 2018 Posts: 228 Location: Melbourne, Australia	Posted: Thu Jun 13, 2019 12:42 am
	This may be a silly question but the two systems seem to be able to play each others games (with little modifications) is this because they use the same chips or because they use the same chips that have been placed in the same layout? I hope that question makes sense.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14740 Location: London	Posted: Thu Jun 13, 2019 6:16 am
	It's because they use the same chips. In a software sense they don't have the same layout, you have to change things around for it to work. Similarly MSX has the same CPU and video chip, and RAM and ROM is pretty universally used.

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