custom co-processor chips like the SVP?

For anything related to cart (SRAM, SF2 mapper, audio, CD mode 1, ...)

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doragasu
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Post by doragasu » Sun Oct 21, 2012 11:28 am

I was talking about this or this.

They are 600 MIPS (really 600 MMACs) devices, with 32/64 kiB internal dual port RAM. The internal ROM is read only. It has the bootloader and some utilities (like a sine LUT). The bootloader is pretty flexible. It can boot from external memory (via parallel or SPI interface), UART and HPI (Host Port Interface). Maybe the HPI would be the best option for a cart. Using HPI, the Megadrive would be able to directly access the internal memory of the DSP. It could upload code and data to the DSP internal RAM and also retrieve the processed data.

RayR
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Can we Kickstart this

Post by RayR » Fri Dec 07, 2012 5:16 am

Growing up I always wanted the Genesis to have extra power and put the SNES in it's place. We didn't have Star Fox and that's the game I envied the most but I would never buy a SNES as I was a Sega fan through and through. Now many years later I think more and more often about programming something retro flavored but with some more advanced arcade effects. Two of my favorite arcade games of all time are Ajax/Typhoon and Assault which had fantastic 2d scale and rotation effects. I would love to tackle some ideas that I've designed doc'd up all these years later and recapture the magic that I missed. They say you can't go home again, but just maybe with a DSP cart I think I just might be able to. I would love to put some money towards a kickstart or contribute to some prototypes. I can solder and have a scope and meters and time but I'm no hardware engineer. I would love to encourage those out there and in this thread who are, to start something. You wouldn't be alone. I think there are many out there who feel the same way I do. What do you think.

tinctu
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Post by tinctu » Fri Dec 07, 2012 10:44 am

What about ADI Blackfin DSP MCU->
http://www.analog.com/en/processors-dsp ... Processors

For example:
ADSP-BF592 - 400MHz, 800MMACS, 68KBytes, SRAM for 1,99USD

Or XMOS DSP MCU->
http://www.xmos.com/discover/products/x ... ral#xs1-l1

For example:
XS-1 L1

400MIPS or 500MIPS
8 concurrent, deterministic processing cores
64KB single-cycle SRAM for code and data storage
Up to 64 programmable I/O ports
Support for high performance DSP (32 x 32 to 64bit MAC) and cryptographic functions

Price: 7,95USD

Or Parallax Propheller:
http://www.parallax.com/propeller/

For example:

Model Number: P8X32A-D40
Processors (cogs): Eight
Architecture: 32-bits
System Clock Speed: DC to 80 MHz
Global RAM/ROM: 64 K bytes; 32 K RAM / 32 K ROM
Cog RAM: 512 x 32 bits each
I/O Pins: 32 (simultaneously addressable by all eight cogs)
Current Source/Sink per I/O: 40 mA
Clock Modes: (a) External crystal 4 -8 MHz (16 x PLL) (b) Internal oscillator ~12 MHz or ~20 kHz (c) Direct drive
Package Type: 40-pin DIP


Price: 7,99USD

Or what about STM32F4 ARM MCU with build in DSP?
http://www.digikey.com/product-highligh ... 32-f4/1486

Core: ARM 32-bit Cortex™-M4 CPU with FPU

Adaptive real-time accelerator (ART Accelerator™) allowing 0-wait state execution from Flash memory, frequency up to 168 MHz, memory protection unit, 210 DMIPS/1.25 DMIPS/MHz (Dhrystone 2.1), and DSP instructions

Memories

Up to 1 Mbyte of Flash memory
Up to 192+4 Kbytes of SRAM

Price: 11,45USD

What about FPGA turbocard:
- TG68 core http://opencores.org/project,tg68 running 21MHz ()
- T80 Core http://opencores.org/project,t80
- VDP Yamaha V9958 core
- external sram

Yamaha V9958:

Video RAM: 128 KB + 64 KB of expanded VRAM
Text modes: 80 x 24 and 32 x 24
Resolution: 512 x 212 (4 or 16 colours out of 512) and 256 x 212 (16, 256, 12499 or 19268 colours)
Sprites: 32, 16 colours, max 8 per horizontal line
Hardware acceleration for copy, line, fill, etc.
Interlacing to double vertical resolution
Horizontal and vertical scroll registers

Raspberry PI as turbocard:
ARM1176JZF-S 700 MHz processor (The firmware includes a number of "Turbo" modes so that the user can attempt overclocking, up-to 1 GHz, without affecting the warranty),VideoCore IV GPU, and originally shipped with 256 megabytes of RAM, later upgraded to 512MB.
8 × GPIO, UART, I²C bus, SPI bus with two chip selects, +3.3 V, +5 V, ground

- Raspberry will works as accelerator or VDP emulator...
Simply boot special IMG from SD and communicate via EXP port...

Price: 25USD - 35USD


CARTRIDGE or EXP PORT Interface CONCEPT:
- turbocard CPU and VDP
- booting from MCU or external FLASH / micro SD-CARD
- upgrading firmware = upgrading MCU via mini USB
- SD CARD or build in flash+USB (for example 16GB Flash)
- low price (max 40 euros)

Chilly Willy
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Post by Chilly Willy » Fri Dec 07, 2012 6:38 pm

Most of those are not well known, and obscure processors mean a lack of tools. Try finding gcc for the propeller. :lol:

The two best choices from your list is an ARM processor, or an FPGA. An FPGA would be harder for many people to deal with since you "program" it at a hardware level.

There are a number of carts out that use an ARM processor for acceleration, especially for the Atari 2600 - the most popular cart has an ARM chip, and it can be used in games. A number of A2600 homebrew use it, so emulating the ARM chip is in 2600 emulators like Stella now.

But we're SEGA folk here, so we want to consider more "SEGA"-ish choices, like the SH2, or I'd say a ColdFire chip since ColdFire is the successor to the 68K family.

tinctu
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Post by tinctu » Fri Dec 07, 2012 6:50 pm

Coldfire or another 68k successor sounds good to me too...

sega16
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Location: U.S.A.

Post by sega16 » Fri Dec 07, 2012 10:55 pm

Chilly Willy wrote:Try finding gcc for the propeller. :lol:
http://code.google.com/p/propgcc/
I found it :D

Chilly Willy
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Post by Chilly Willy » Fri Dec 07, 2012 11:15 pm

sega16 wrote:
Chilly Willy wrote:Try finding gcc for the propeller. :lol:
http://code.google.com/p/propgcc/
I found it :D
Nifty! But propeller isn't really a good choice for a console accelerator. :D

Here's a V4 ColdFire that's $12.68 in single unit quantities from DigiKey... the main problem here is it would need a level shifter for the interface to the cart port. That'll be an issue most new high performance chips will have - they're all designed around modern low-voltage buses.

You can get 50MHz V1 ColdFire that work with 5V buses, but they're more limited... but they're also under $10!

Personally, I like the SuperH chips the best.

tinctu
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Post by tinctu » Fri Dec 07, 2012 11:55 pm

"You can get 50MHz V1 ColdFire that work with 5V buses, but they're more limited... but they're also under $10! "
Sounds good!

Hitachi is still producing SHs???
Best choose will be actual CPU supported by manufacturer...
I like SH-4 from Dreamcast.
DMA is good...

Are there free tools for SH CPUs? C? Or Pascal (yes I love Turbo Pascal)?

Best will be to have DAC on cartridge too. For MOD/XM/S3M replay.
There are lot of free trackers.
YM and SN will be for music (VGM MM) and DAC for digital samples (explosions, kicks, laser etc) or digital music (AMIGA like).
And best will be to have SRAM or FLASH plus USB (flash cartridge as mass storage or hid device on PC) on cartridge and dimensions like standard SEGA cartridge.
Last edited by tinctu on Sat Dec 08, 2012 12:08 am, edited 2 times in total.

Mask of Destiny
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Post by Mask of Destiny » Sat Dec 08, 2012 12:03 am

Chilly Willy wrote: Here's a V4 ColdFire that's $12.68 in single unit quantities from DigiKey... the main problem here is it would need a level shifter for the interface to the cart port. That'll be an issue most new high performance chips will have - they're all designed around modern low-voltage buses.
It's also in a 256 pin BGA package. Have fun prototyping that.
Chilly Willy wrote:You can get 50MHz V1 ColdFire that work with 5V buses, but they're more limited... but they're also under $10!
A number of them support USB OTG as well. Not useful for a pure graphics accelerator, but you could use it to support a hard drive/thumb stick or USB gamepad.

tinctu
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Post by tinctu » Sat Dec 08, 2012 12:07 am

"A number of them support USB OTG as well. Not useful for a pure graphics accelerator, but you could use it to support a hard drive/thumb stick or USB gamepad."

USB gamepad or USB keyboard or USB mouse will be super cool...
Imagine playing jump and run games with PC gamepad, arkanoid like games with mouse or strategy games with USB keyboard...

Or using USB flashdisk as storage... Amazing.

Chilly Willy
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Post by Chilly Willy » Sat Dec 08, 2012 2:44 am

Yes, BGA is a real pain for protos. You'd really need an adapter for it until you had it all done. The SuperH (which is made by Renesas these days, not Hitachi) is easier to get in flat packs, which is another reason I like SuperH better. :D

ammianus
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Post by ammianus » Sat Dec 08, 2012 1:47 pm

Maybe I don't get it (typical), but how would putting chips on the cart be better than actually using the 2 SH2 CPUs on the 32X the same way and making 32X games? :) I believe ob1 is actually doing something like this with his SuperVDP technique which uses both 32X CPUs to draw graphics requested from the MD, as I understand it. Also would we expect performance of games to be much different/better this way than through 32X?

I guess if you don't own a 32X then maybe this would appeal? Or since there are newer CPUs now and possibility of more work memory on the cart as well?

What about using this same technique to increase offload some of 32X work to the cart :D?

If you can't tell I have a bias here.

tinctu
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Post by tinctu » Sat Dec 08, 2012 2:59 pm

When you will put there 250mhz Freescale 68k or 800mhz ARM with DSP instructions you will see the difference...

Chilly Willy
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Post by Chilly Willy » Sat Dec 08, 2012 5:40 pm

The thread covers making an SVP-like cart that could be used on the Genesis. It's discounting the 32X, but I suppose you could make it work with the 32X as well for even faster 32X games. A 200+ MHz SH2/3 or ColdFire or ARM with 16 to 512 MB of ram would make some games pretty easy. You'd just be using the Genesis/32X as the display/sound/controls.

As I mentioned, there's a cart that does this for the Atari 2600 - you run the game (or at least the parts that take the most time) on the ARM, and output the display and sound on the 2600. You get games that look like 2600 games, but well beyond what you thought you'd ever see. Look at the Space Rocks thread over at Atari Age for an example.

RayR
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Post by RayR » Sat Dec 08, 2012 7:23 pm

I'm glad this thread didn't die with my last post. I'm really excited that there's more discussion and people are sounding serious. I checked the Space Rock thread and was impressed. I'm sure the Mega Drive cart with DSP will produce highly polished results when it's finished :D . Please don't think I'm making presumptions. I know it will happen sooner or later as there is to much passion and motivation in the Sega community for it not to happen. It's inevitable. I'm seriously ready for the new Sega retro Renaissance. The Mega Drive\Genesis won't die, it's legacy can only continue with something like this. Like I said before I'm ready to contribute funds for development and engineering. Lets do this.

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