32k Flash Cart Rev. 2

[LinkoVitch]

Why else would we have toes?

 

For playing the piano obviously!

[+Kaboomer]

Is there a web site for your project? Would love to see it! Also, put me on your pre-order list! This sounds really cool and I missed out on Cuttle!

[cschell]

I am soldering the first prototype as we type.

 

Assuming the prototype is soldered...does it work?

 

Chad

[mvigor]

I'm also very eager to find out how the progress is going.

[Cupcakus]

It works great if I give it 30 minutes to program :-)

 

I am working with some electronics folks to figure out why when I speed it up things go nuts... It is much more complicated than I had wished, but isn't it always :-)

 

Never fear though... I have not and will not drop this project... it will arrive :-)

 

Thanks for checking up on me :-)

[Cupcakus]

All I have is a webcam sorry for the pics... but at least everyone knows I'm not pulling your leg :-)

 

I REALLY am working on this! I swear it!

[Cupcakus]

I just realised I have a sexy thumb :-) Oh yeah...

 

ha ha

 

[Cupcakus]

The John Madden version...

[Paul Slocum]

Hehe -- looks just like my first menu multicart prototype. Seeing all those wires brings back the pain. Cut wire, check diagram, solder, repeat (for many hours.)

 

-Paul

[Cupcakus]

Hehe -- looks just like my first menu multicart prototype.  Seeing all those wires brings back the pain.  Cut wire, check diagram, solder, repeat (for many hours.)

 

-Paul

 

HOURS!!! How did you get so lucky :-) I think I'm on week two...

[Goochman]

If you took the spaghetti overlay out maybe we could see the board

[Paul Slocum]

HOURS!!! How did you get so lucky :-) I think I'm on week two...    

 

I was just talking about assembling it. Debugging is a whole different painful story. I built the first one on one of those socketed breadboards, then I built a smaller one to fit in a cartridge which stopped working when I was nearly done and I never could find the problem, then I started over and built a third one which was my final version. Now I remember why I don't do hardware anymore!

 

[Richard H.]

Here's a pic of my 2600 RAM-cart proto. The EPROM is in place of the SRAM for bank-switch testing purposes.

 

 

 

 

Richard H.

[CPUWIZ]

I am curious, looking at the picture I see a crystal and 2 caps, that leads me to believe that the big chip is a PIC16F877. Is that correct ?

[Rob Mitchell]

Here's a pic of my 2600 RAM-cart proto. The EPROM is in place of the SRAM for bank-switch testing purposes.

 

Hi Richard!

 

Your prototype looks good!

 

Rob Mitchell, Atlanta, GA, USA

[Cupcakus]

Here's a pic of my 2600 RAM-cart proto. The EPROM is in place of the SRAM for bank-switch testing purposes.

 

Hi Richard!

 

Your prototype looks good!

 

Rob Mitchell, Atlanta, GA, USA

 

Hey I'm jelous :-)

 

This thread is for my proto... :-)

[Richard H.]

I am curious, looking at the picture I see a crystal and 2 caps, that leads me to believe that the big chip is a PIC16F877. Is that correct ?

 

Yes, you are correct.

 

It's being used for the bank-switching + also to download data serially from a PC to the SRAM.

 

The download bit is tried and tested and works great (see VecRAM)

 

The bankswitch bit on the otherhand is not working correctly.

 

I'm really hoping it's just the address read glitch, and not something serious like the PIC not being fast enough.

 

I did have it sort of working on a 2 bank-switching game the other day, but the display was continually rolling for some reason.

 

I've left it alone for quite a while to concentrate on Vec hardware. But recently I've gone back to tinkering with it, as Rob suggested there might be some interest in a Cuttle cart type device.

[BrainDrain]

Mate, that thing looks damn great!!!

 

If only i knew what it does............

 

Maybe i shoulda spent more time concentrating in electronics class in high school. I was decent at soldering however

 

But seriously, how much spare time do you have on your hands???

[Cupcakus]

I am curious, looking at the picture I see a crystal and 2 caps, that leads me to believe that the big chip is a PIC16F877. Is that correct ?

 

Yes, you are correct.

 

It's being used for the bank-switching + also to download data serially from a PC to the SRAM.

 

The download bit is tried and tested and works great (see VecRAM)

 

The bankswitch bit on the otherhand is not working correctly.

 

I'm really hoping it's just the address read glitch, and not something serious like the PIC not being fast enough.

 

I did have it sort of working on a 2 bank-switching game the other day, but the display was continually rolling for some reason.

 

I've left it alone for quite a while to concentrate on Vec hardware. But recently I've gone back to tinkering with it, as Rob suggested there might be some interest in a Cuttle cart type device.

 

Competition already... and I havn't even gotten half way through yet :-) How does your RAM cart work... how do you program it??? How much memory is on it? Is it nonvolatile? What bankswitching schemes do you plan to use?

[CPUWIZ]

The 16F877 is a pretty powerful microcontroller with lots of I/O lines, you should check out the specs at Microchip.com it has a UART, serial blah blah. You can clock that thing up to 20Mhz, I have played around with almost the exact same thing as Richard H. except I was doing it on a breadboard. Right now it's sitting in one of my project drawers waiting.

 

You've had competition in this sort of thing for a long time I think, actually you are the competition since you just started.

[Cupcakus]

How are you going to present a clock line to a MicroController??? and keep it synched and fast enough to handle bankswitching... I think true logic is the only way to achieve total bankswitching... that is what Chad used... as well as myself...

 

And I guess I am the competition :-) The problem is I started my project out of necessity, due to no development carts for the 2600... the CC has been out of service for quite some time and I have heard nothing from either of you :-) So I took on the time and expense to work this out and build my own...

 

And NOW you guys show up :-) Figures.... :-)

 

Things are finally moving forward for me quite quickly, I have the major BS types working now... F8/F6/F4, the challenge of course is the superchip and other RAM enabled carts... So hopefully I will be done very soon....

 

I can imagine getting pretty upset if I went through all of this trouble to get this thing working and then you guys come out with yours and i could have saved tons of time and just bought one of those... :-)

[CPUWIZ]

Thats great news, I wouldn't worry about any other carts "coming out", keep going, there is quite a few interested people around.

 

BTW, do you really care about those few games that used RAM+ etc. ?

 

Also, have you looked into 3F bankswitching ?

[Cupcakus]

I will be supporting CV RAM+ and Superchip RAM.. however I won't be supporting M-Network RAM... I see no reason to figure out how to implement 2k of RAM for one crappy game...

 

However the SuperChip was used on a great deal of games, and I will be supporting that one... and RAM+ is nothing more than a bigger superchip, so there is no reason why I can't throw that one in too...

 

I plan to support all BS types, including 3F... I have not tested 3F yet however....

[cschell]

CPUWIZ and Richard:

 

I don't think PICs are fast enough to do Atari bankswitching. They run at only 5MHz max, which leaves less than 5 instructions per Atari clock cycle. Given that a jump command takes 2 instruction cycles on a PIC, that means that your loop could only have three instructions and still execute every 2600 cycle. The PIC is 8 bit, so you need to compare the inputs on two ports to detect a bankswitch address. Just reading both ports is two cycles minimum. Uh oh....

 

Cupcakus:

 

Do you really have F8/F6/F4 working? The parts you pointed out on your board don't seem to possess any sort of comparator to implement even F8. Are you just not pointing out other parts hidden under the wires, are does the bankswitching work only in theory?

 

You also realize that to do Superchip games you'll need SRAM on the board as your eeprom is almost certainly not fast enough to serve that purpose, right? It also greatly complicates the deglitching required.

 

Everyone:

 

Sigh. As I suddenly find myself with free time, the temptation to put out another run of Cuttle Carts grows.

 

Chad

[CPUWIZ]

Incorrect, the 16F877 runs at 20Mhz, even the 16F84 can be clocked at 10Mhz. Some of the newer ones go even higher.

 

You couldn't do many bankswitching schemes with it but a couple. Like I said, it's just tinkering for me, not for public release.