Atari VCS 2600 FPGA Cartridge

Hey programmable logic seniors! I'm planning to build an Atari VCS
2600 game cartridge in order to play with my "brand new" console
acquired from ebay. I would like to replace the old fashioned 27C
series EPROM by a programmable device thus cutting board space and
(main reason) merging the bankswitching logic and rom file in a single
device. My requirements are 32k x 8 (64k is a plus) of non volatile
memory and some space to house a couple of FFs and logic gates (simple
equations). My question is: which manufacturer, family and/or device
should I look for? Thanks for sharing your valuable experience with my
hobby project.

On 19 avr, 05:34, Darcio Prestes <darciopres...@gmail.com> wrote:
> Hey programmable logic seniors! I'm planning to build an Atari VCS
> 2600 game cartridge in order to play with my "brand new" console
> acquired from ebay. I would like to replace the old fashioned 27C
> series EPROM by a programmable device thus cutting board space and
> (main reason) merging the bankswitching logic and rom file in a single
> device. My requirements are 32k x 8 (64k is a plus) of non volatile
> memory and some space to house a couple of FFs and logic gates (simple
> equations). My question is: which manufacturer, family and/or device
> should I look for? Thanks for sharing your valuable experience with my
> hobby project.

I've done something close to what you're looking for, I guess.
See http://torlus.com/index.php?2008/08/25/219-2600-monocart-assembled-and-working-sort-of
The idea is to use non-volatile RAM, and program it via USB with the
help of a small MCU.
Bankswitching is performed by a small CPLD.
Unfortunately, it doesn't work with the NVRAM chip I've chosen.Maybe
I'll work again on it later, but well, I can't guarantee that.
Feel free to ask some questions if you're interested in it.

You may also have a look at AtariAge's forum, and search for
"Chimera", a full-featured flash cart project using a FPGA, much more
advanced than what I've done so far on this subject.

Hope this helps,
Greg

On Apr 19, 4:38=A0am, Gregory Estrade <gregory.estr...@gmail.com> wrote:
> On 19 avr, 05:34, Darcio Prestes <darciopres...@gmail.com> wrote:
>
> > Hey programmable logic seniors! I'm planning to build an Atari VCS
> > 2600 game cartridge in order to play with my "brand new" console
> > acquired from ebay. I would like to replace the old fashioned 27C
> > series EPROM by a programmable device thus cutting board space and
> > (main reason) merging the bankswitching logic and rom file in a single
> > device. My requirements are 32k x 8 (64k is a plus) of non volatile
> > memory and some space to house a couple of FFs and logic gates (simple
> > equations). My question is: which manufacturer, family and/or device
> > should I look for? Thanks for sharing your valuable experience with my
> > hobby project.
>
> I've done something close to what you're looking for, I guess.
> Seehttp://torlus.com/index.php?2008/08/25/219-2600-monocart-assembled-an.=
..
> The idea is to use non-volatile RAM, and program it via USB with the
> help of a small MCU.
> Bankswitching is performed by a small CPLD.
> Unfortunately, it doesn't work with the NVRAM chip I've chosen.Maybe
> I'll work again on it later, but well, I can't guarantee that.
> Feel free to ask some questions if you're interested in it.
>
> You may also have a look at AtariAge's forum, and search for
> "Chimera", a full-featured flash cart project using a FPGA, much more
> advanced than what I've done so far on this subject.
>
> Hope this helps,
> Greg

   Hi Greg. I checked out your project. Excellent work. I first
realized putting a microcontroller connected direct on 2600 cartridge
slot and writing some code to make some sort of DMA between the
console and the uC flash memory. This actualy have been done by the
folks at Atari Age in Harmony Cart. The site even sells a cart kit
using EPROM and a GAL to handle the additional equations of
bankswitching when needed.

   What I'm looking for is to replace all that circuitry with a single
combinational chip. I know that prices of progammable logic have been
dramaticaly decreased during the last years. So I imagined it could be
$ viable to use that kind of device to achieve the goal. Of course I
can use a huge CPLD with thousands of "cells" to accomplish the task
but I would like to hear from you here (once I don't have enough
practical experience with programmable logic) what device should I
consider. The optimal requirements as I stated before are:

A) Space to store a 32 kb x 8 ROM file;
B) Additional space for bankswitching logic;
C) 5 Volts;
D) Non volatile.

I hope to get some directions :)

On Apr 19, 8:09=A0pm, Darcio Prestes <darciopres...@gmail.com> wrote:
> On Apr 19, 4:38=A0am, Gregory Estrade <gregory.estr...@gmail.com> wrote:
>
>
>
>
>
> > On 19 avr, 05:34, Darcio Prestes <darciopres...@gmail.com> wrote:
>
> > > Hey programmable logic seniors! I'm planning to build an Atari VCS
> > > 2600 game cartridge in order to play with my "brand new" console
> > > acquired from ebay. I would like to replace the old fashioned 27C
> > > series EPROM by a programmable device thus cutting board space and
> > > (main reason) merging the bankswitching logic and rom file in a singl=
e
> > > device. My requirements are 32k x 8 (64k is a plus) of non volatile
> > > memory and some space to house a couple of FFs and logic gates (simpl=
e
> > > equations). My question is: which manufacturer, family and/or device
> > > should I look for? Thanks for sharing your valuable experience with m=
y
> > > hobby project.
>
> > I've done something close to what you're looking for, I guess.
> > Seehttp://torlus.com/index.php?2008/08/25/219-2600-monocart-assembled-a=
n...
> > The idea is to use non-volatile RAM, and program it via USB with the
> > help of a small MCU.
> > Bankswitching is performed by a small CPLD.
> > Unfortunately, it doesn't work with the NVRAM chip I've chosen.Maybe
> > I'll work again on it later, but well, I can't guarantee that.
> > Feel free to ask some questions if you're interested in it.
>
> > You may also have a look at AtariAge's forum, and search for
> > "Chimera", a full-featured flash cart project using a FPGA, much more
> > advanced than what I've done so far on this subject.
>
> > Hope this helps,
> > Greg
>
> =A0 =A0Hi Greg. I checked out your project. Excellent work. I first
> realized putting a microcontroller connected direct on 2600 cartridge
> slot and writing some code to make some sort of DMA between the
> console and the uC flash memory. This actualy have been done by the
> folks at Atari Age in Harmony Cart. The site even sells a cart kit
> using EPROM and a GAL to handle the additional equations of
> bankswitching when needed.
>
> =A0 =A0What I'm looking for is to replace all that circuitry with a singl=
e
> combinational chip. I know that prices of progammable logic have been
> dramaticaly decreased during the last years. So I imagined it could be
> $ viable to use that kind of device to achieve the goal. Of course I
> can use a huge CPLD with thousands of "cells" to accomplish the task
> but I would like to hear from you here (once I don't have enough
> practical experience with programmable logic) what device should I
> consider. The optimal requirements as I stated before are:
>
> A) Space to store a 32 kb x 8 ROM file;
> B) Additional space for bankswitching logic;
> C) 5 Volts;
> D) Non volatile.
>
> I hope to get some directions :)- Hide quoted text -
>
> - Show quoted text -

The ONLY part that satisfies ALL requirements is: ice65L16 from
SiliconBlue

this mainly because of 5V requirement
finding device with 32k ram is easy, but it will not be 5V tolerant
so you need to compromise on something

Antti

Antti.Lukats@googlemail.com wrote:
> The ONLY part that satisfies ALL requirements is: ice65L16 from SiliconBlue
A SBt employee told me that it is not available very soon (end of year ?).
On top of that, is it 5V-tolerant on enough pins ?

> Antti
yg
-- 
http://ygdes.com / http://yasep.org

On 19 abr, 14:33, "Antti.Luk...@googlemail.com"
<Antti.Luk...@googlemail.com> wrote:
> On Apr 19, 8:09=A0pm, Darcio Prestes <darciopres...@gmail.com> wrote:
>
>
>
> > On Apr 19, 4:38=A0am, Gregory Estrade <gregory.estr...@gmail.com> wrote=
:
>
> > > On 19 avr, 05:34, Darcio Prestes <darciopres...@gmail.com> wrote:
>
> > > > Hey programmable logic seniors! I'm planning to build an Atari VCS
> > > > 2600 game cartridge in order to play with my "brand new" console
> > > > acquired from ebay. I would like to replace the old fashioned 27C
> > > > series EPROM by a programmable device thus cutting board space and
> > > > (main reason) merging the bankswitching logic and rom file in a sin=
gle
> > > > device. My requirements are 32k x 8 (64k is a plus) of non volatile
> > > > memory and some space to house a couple of FFs and logic gates (sim=
ple
> > > > equations). My question is: which manufacturer, family and/or devic=
e
> > > > should I look for? Thanks for sharing your valuable experience with=
 my
> > > > hobby project.
>
> > > I've done something close to what you're looking for, I guess.
> > > Seehttp://torlus.com/index.php?2008/08/25/219-2600-monocart-assembled=
-an...
> > > The idea is to use non-volatile RAM, and program it via USB with the
> > > help of a small MCU.
> > > Bankswitching is performed by a small CPLD.
> > > Unfortunately, it doesn't work with the NVRAM chip I've chosen.Maybe
> > > I'll work again on it later, but well, I can't guarantee that.
> > > Feel free to ask some questions if you're interested in it.
>
> > > You may also have a look at AtariAge's forum, and search for
> > > "Chimera", a full-featured flash cart project using a FPGA, much more
> > > advanced than what I've done so far on this subject.
>
> > > Hope this helps,
> > > Greg
>
> > =A0 =A0Hi Greg. I checked out your project. Excellent work. I first
> > realized putting a microcontroller connected direct on 2600 cartridge
> > slot and writing some code to make some sort of DMA between the
> > console and the uC flash memory. This actualy have been done by the
> > folks at Atari Age in Harmony Cart. The site even sells a cart kit
> > using EPROM and a GAL to handle the additional equations of
> > bankswitching when needed.
>
> > =A0 =A0What I'm looking for is to replace all that circuitry with a sin=
gle
> > combinational chip. I know that prices of progammable logic have been
> > dramaticaly decreased during the last years. So I imagined it could be
> > $ viable to use that kind of device to achieve the goal. Of course I
> > can use a huge CPLD with thousands of "cells" to accomplish the task
> > but I would like to hear from you here (once I don't have enough
> > practical experience with programmable logic) what device should I
> > consider. The optimal requirements as I stated before are:
>
> > A) Space to store a 32 kb x 8 ROM file;
> > B) Additional space for bankswitching logic;
> > C) 5 Volts;
> > D) Non volatile.
>
> > I hope to get some directions :)- Hide quoted text -
>
> > - Show quoted text -
>
> The ONLY part that satisfies ALL requirements is: ice65L16 from
> SiliconBlue
>
> this mainly because of 5V requirement
> finding device with 32k ram is easy, but it will not be 5V tolerant
> so you need to compromise on something
>
> Antti

Thanks for replying. It's possible to use level translation so we can
drop the 5V requirement. Our range is now broader.

Darcio Prestes wrote:
> On 19 abr, 15:39, whygee <why...@yg.yg> wrote:
>> Antti.Luk...@googlemail.com wrote:
>>> The ONLY part that satisfies ALL requirements is: ice65L16 from SiliconBlue
>> A SBt employee told me that it is not available very soon (end of year ?).
>> On top of that, is it 5V-tolerant on enough pins ?
>>
>>> Antti
>> yg
>> --http://ygdes.com/http://yasep.org
> 
> YG brought an important question. Data bus is 8 bit wide and address
> bus is 12 bit wide. I want to add 4 switches so the count is 24 pins
> or higher.

I think that the ice65L16 is going to take too much time to appear on
the market and mature, for such a "little project".
Level translation buffers are a good solution, given the slow cycle
time (IIRC) of the VC2600 (someone asked me to design a cartridge
some years ago, I didn't go far but remember a few things).
I think that something like the sn74lvcc4245
or sn74lvcc3245 (depending on what circuit controls the bus direction)
is suitable (it works well on an ISA bus).

While we're at it, the games could be stored in a small serial flash
such as http://it.farnell.com/jsp/search/productdetail.jsp?sku=1455042
or similar parts. If you're going to use a huge FPGA (since you need a lot
of SRAM blocks), then there will be a lot a free logic blocks,
so a few can be used to do the SPI protocol interface.

Now, my greedy side tells me that a fast SRAM (15ns) of 64K*8
does cost only a few $ (and I just got larger chips for even cheaper).
Look at old Pentium motherboards, they used to have 8 chips of 32K bytes
(some have 64KB). So you can spare the huge, expensive and underused FPGA
that will probably come with a large and/or BGA package.

happy hacking,
yg

-- 
http://ygdes.com / http://yasep.org

On 19 abr, 15:39, whygee <why...@yg.yg> wrote:
> Antti.Luk...@googlemail.com wrote:
> > The ONLY part that satisfies ALL requirements is: ice65L16 from SiliconBlue
>
> A SBt employee told me that it is not available very soon (end of year ?).
> On top of that, is it 5V-tolerant on enough pins ?
>
> > Antti
>
> yg
> --http://ygdes.com/http://yasep.org

YG brought an important question. Data bus is 8 bit wide and address
bus is 12 bit wide. I want to add 4 switches so the count is 24 pins
or higher.

On 19 abr, 15:39, whygee <why...@yg.yg> wrote:
> Antti.Luk...@googlemail.com wrote:
> > The ONLY part that satisfies ALL requirements is: ice65L16 from SiliconBlue
>
> A SBt employee told me that it is not available very soon (end of year ?).
> On top of that, is it 5V-tolerant on enough pins ?
>
> > Antti
>
> yg
> --http://ygdes.com/http://yasep.org

YG brought an important question. The data bus is 8 bit wide and
address bus is 12 bit wide. I want to add 4 switches so the count is
24 pins or higher.

whygee wrote:
> I think that the ice65L16 is going to take too much time to appear on
> the market and mature, for such a "little project".
However, when it becomes ready, and if a suitable package
(like QFP100, not BGA or QFN) is available, this would be
perfect : one could store 4 different games without effort,
because the chip can read 4 off-chip images (including SRAM contents)
depending on the state of 2 inputs pins. But how much will it cost ?

yg
-- 
http://ygdes.com / http://yasep.org