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Posted: Sun Aug 09, 2015 8:36 am
by HardWareMan
ASIC chips are ready. With handy for probing pins.
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I visited the idea: I can experience them out of MD environment. I can make testbench for TA-04 and TA-05. TA-06 too complex for this.

Posted: Mon Aug 10, 2015 1:04 am
by Charles MacDonald
I visited the idea: I can experience them out of MD environment. I can make testbench for TA-04 and TA-05. TA-06 too complex for this.
Very nice! Is there a reason why you are looking at the clone chips instead of the originals? Do the clone parts have some interesting or undocumented functions?

Posted: Mon Aug 10, 2015 4:36 am
by HardWareMan
The reason is simple: I don't have any of it. Beside, as I know the TA chipset most accurate clone to original. For example, this TA-04 was replaced by me more than 15 years ago and it still works (burned out arbiter was the reason to change this superclone to onechip MD2 clone):
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Anyway, it is better that system was divided into units and testing that units separately is much easier than whole system. You always can assemble those parts into one unit, right?

Posted: Fri Aug 21, 2015 8:22 pm
by ob1
HAve you guys heard about retro VGS (http://www.retrovgs.com) ?
It's an ARM Cortex 8 (single core, 1GHz) coupled with a 49k EL FPGA.

Posted: Sat Aug 22, 2015 4:14 am
by HardWareMan
ob1 wrote:HAve you guys heard about retro VGS (http://www.retrovgs.com) ?
It's an ARM Cortex 8 (single core, 1GHz) coupled with a 49k EL FPGA.
We don't need yet another emulator. We want a simulator.

Posted: Sat Aug 22, 2015 6:04 am
by ob1
Of course, of course, I know.
I just wanted to drop the specs.
I was thinking about Kaneda line :
... i'll like to know if a FPGA (or a SoC) version of Genny is possible ? ...
In this "Retro VGS", in what I thought was related, the ARM would be idle, while the FPGA would be the actual Genesis.
Not emulated.
Just FPGA-simulated.

Sorry if off-topic.

Re: FPGA version

Posted: Wed Apr 20, 2016 6:01 pm
by HardWareMan
Some update.
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Need to allocate some time to build working DIY prototype.

Re: FPGA version

Posted: Wed Jan 25, 2017 12:00 pm
by bastien
Good works.
It Could be interessting.
It à clone of what chip ?

Re: FPGA version

Posted: Wed Aug 23, 2023 5:29 pm
by HardWareMan
Ok, our team almost done reverse engineering MD ASICs with it's decap. Some of team members was made a hardware level emulator and even FPGA one. Now my turn to finish this project. Finally I done with this:
Image
This is Megadrive that rebuild on custom PCB with possibility to replace the ASICs. I'm gonna recreate the ASICs in CPLD/FPGA and try it in this PCB. There is RAM underneath the ASICs modules.
Image
I found the 1Mx8 5V SRAM chips, so this model able to use 2MB of RAM (from $E00000 through $FFFFFF), but in compatibility purpose it can be reduced to standard 64KB with mirroring. Also I use one half of 32KB chip on the Z80 side. So there avaiable 16KB from $0000 through $3FFF but also can be reduced to standard 8KB with mirroring. VDP mode pin was isolated from region register input at I/O, so able to set all 4 regions on 50Hz or 60Hz VDP mode.
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Almost 6 years passed since I posted here pictures of ASICs modules (links to those pictures are dead now) and almost 10 years since I started this project. Now I hope I can finish it, lol.

Re: FPGA version

Posted: Mon Sep 04, 2023 5:21 pm
by danibus
HardWareMan wrote:
Wed Aug 23, 2023 5:29 pm
Ok, our team almost done reverse engineering MD ASICs with it's decap. Some of team members was made a hardware level emulator and even FPGA one. Now my turn to finish this project. Finally I done with this:
Image
This is Megadrive that rebuild on custom PCB with possibility to replace the ASICs. I'm gonna recreate the ASICs in CPLD/FPGA and try it in this PCB. There is RAM underneath the ASICs modules.
Image
I found the 1Mx8 5V SRAM chips, so this model able to use 2MB of RAM (from $E00000 through $FFFFFF), but in compatibility purpose it can be reduced to standard 64KB with mirroring. Also I use one half of 32KB chip on the Z80 side. So there avaiable 16KB from $0000 through $3FFF but also can be reduced to standard 8KB with mirroring. VDP mode pin was isolated from region register input at I/O, so able to set all 4 regions on 50Hz or 60Hz VDP mode.
Image
Almost 6 years passed since I posted here pictures of ASICs modules (links to those pictures are dead now) and almost 10 years since I started this project. Now I hope I can finish it, lol.
Hope you finish. It will be great!
We had mega sg fpga but not sure if you can use their work.

Re: FPGA version

Posted: Tue Sep 05, 2023 6:40 am
by HardWareMan
danibus wrote:
Mon Sep 04, 2023 5:21 pm
We had mega sg fpga but not sure if you can use their work.
I'll use only our decap project as source. I don't want to use any other one's.

Re: FPGA version

Posted: Wed Nov 01, 2023 4:50 am
by AmateurSegaDev
What a beauty, super impressive! Hope you can cross that finish line!