FPGA version

[KanedaFr]

While surfing over the net these years, I found at least 3 FPGA versions of the Genesis.

While they all claim their versions aren't finished, i'll like to know if a FPGA (or a SoC) version of Genny is possible ?

Everyone here know several SoC versions of the Genny were made (radica, atgames, ....), sometimes with the help of Sega (shame on them!)
but, perhaps apart the MD pocket, they're all pure crap.

So, is it because it's not possible to get a EXACT copy of the Genny v1 to FPGA/SoC (mainly sounds part) or because they just made it fast and cheap ? is it because we're still missing some technical details to make a perfect clone of any sega chip ?

Let's dream (because it's how things change) :
Is it ever possible to make a Genny v4, open hardware so we can add some dev related stuff ?! (and before you ask, I'm totally against adding feature like mp3, more ram...but not again adding SD card support, HDMI output, ...)

[HardWareMan]

I think even rough program model will be much better in FPGA than on CPU. Full speed in real time and asynchronous of every system blocks will rocks.

[ob1]

I'm totally against adding feature like more ram

Just for the record, why not ?
What's to hate about more ram, more vram or more colors ?
Compatibility ?

[HardWareMan]

Well, there is 3 custom chips in MD: VDP, arbiter and IO. So, I can try to replace them to CPLD clone but without decap it will be base only described behavior (for example from emulator). And VDP will be harder than IO and arbiter together.

[KanedaFr]

@ob1: genny is genny, add something else and it's a mushroom like
My first idea is to get a 'made-with-today-IC' genny, not a new genny
+ I'm very septic about people developping for a dedicated hardware

@hw: so the docs aren't enough, it was my question
without a decap of all the sega chip, it won't be possible....
need to check my contact list

[HardWareMan]

I've already disassemble my clone and going to reincarnate it in version for development. Progress will lay out here. Original PCB:.


I've just notice: Z80 NMI is connected to pin 70 of 315-5364 (TA-04). So, is there ability to use Z80's NMI?

[ob1]

@ob1: genny is genny, add something else and it's a mushroom like
My first idea is to get a 'made-with-today-IC' genny, not a new genny
+ I'm very septic about people developping for a dedicated hardware ;)

@hw: so the docs aren't enough, it was my question :(
without a decap of all the sega chip, it won't be possible....
need to check my contact list ;)

Makes sense.
But I'd more than happily buy a brand new Genesis. Even on FPGA ;)

[ob1]

@ob1: genny is genny, add something else and it's a mushroom like
My first idea is to get a 'made-with-today-IC' genny, not a new genny
+ I'm very septic about people developping for a dedicated hardware ;)

@hw: so the docs aren't enough, it was my question :(
without a decap of all the sega chip, it won't be possible....
need to check my contact list ;)

Makes sense.
And I'd more than happily buy a brand new Genesis. Even on FPGA ;)

[Eke]

I've just notice: Z80 NMI is connected to pin 70 of 315-5364 (TA-04). So, is there ability to use Z80's NMI?

Only in MS compatibility mode (when /M3 pin is grounded) I think, one of the unused cartridge pin (VA23) is connected to the PAUSE button in PBC, which triggers Z80 /NMI when pressed

Out of curiosity, do you know who produced these TA-xx cloned chips and how they were usually made ? By "stealing" original ASICs masks (not sure if that's how they are called) in manufacture and making their own rebranded ones ? I wonder if the original chips design is still available somewhere

[KanedaFr]

@HW: I think you already went as far as my wish' second step
If we have a 'pure' Genny on FPGA, nothing stop us to make a 'dev' genny

I vote for FGPA-PROBE or F PROBE

[Charles MacDonald]

While they all claim their versions aren't finished, i'll like to know if a FPGA (or a SoC) version of Genny is possible ?

The SoC versions are just emulation running on an embedded platform, so it can be as good as the emulation they use (or steal )

A FPGA version that is close to perfect is definitely possible. I think there needs to be a community built around it (like minimig had) so that multiple people are contributing and coordinating things -- the FPGA projects stall because a lot of effort and testing is involved, it can be too much for one or two people to handle.

[KanedaFr]

Thanks for this details, I though SoC was more a full genny board on a chip and FPGA a hardware 'emulation'

My mistake, I'm still a total noob on FPGA.

[HardWareMan]

While they all claim their versions aren't finished, i'll like to know if a FPGA (or a SoC) version of Genny is possible ?

The SoC versions are just emulation running on an embedded platform, so it can be as good as the emulation they use (or steal )

Emulation or simulation? Emulation if they use platform with own processor such NIOS or maybe ARM/MIPS and runs software emulator. Simulation if they make a black box that behaves like true MD and runs native software but inside is not full copy.

In this thread I try to make at least maximum compatible simulator of MD ASIC. If I'm lucky then it will be fully logic copy.

PS: viewtopic.php?t=746

[ob1]

This thread makes perfect sense.
Especially when you see Analogue Interactive releasing a $500 - gorgeous - NES.

[Charles MacDonald]

This thread makes perfect sense.
Especially when you see Analogue Interactive releasing a $500 - gorgeous - NES.

The FAQ mentions that these systems are built up from old consoles using the original CPU and PPU chips that they cannibalized.

I'm sure the HDMI video processing and such is nice, but it's strange that the core of the system isn't a SoC/FPGA version of the NES. Seems like too much effort to bolt on such features to the original chipset.

I have to say, the audiophile type marketing lingo at their page was frustrating to read.