Community-Built Unnamed 1970's Video Game Console-Compatible System (WIP)

[+wongojack]

following

[Thomas Jentzsch]

12 hours ago, Albert said:

Well, I can move it and leave a temporary link available in this forum (which will point to the new location of the thread), and that goes away after 30 days or so.  It would enable people to find the thread in its new location.  Also, there's no way for me to make a copy of a thread as far as I'm aware. 

 

 

 ..Al

@Al_Nafuur can you give Albert your OK, please?

[+Al_Nafuur]

1 hour ago, Thomas Jentzsch said:

@Al_Nafuur can you give Albert your OK, please?

@Albert OK

[+Al_Nafuur]

Has anyone so far setup a breadboard and a Pi to test?

 

My breadboard setup (or the Pi) is misbehaving since yesterday and I cannot get consistent reads (even when dumping a simple 2K cart)

[+5-11under]

I could design a quick PCB layout, and build 10 units, and sell them at basically cost.

I could do the design and PCB ordering fairly quickly, and in a couple of weeks or so, when I'm less busy with PRGE (and boards arrive), I'd be able to assemble them. I'd be able to ship them out around the middle of October, maybe a week sooner.

Otherwise, someone else could do the same.

 

Feel free to add to this design ideas list, whether it's me making them, or someone else. If it's me doing it, the layout will be hopefully done before Sunday:

• Cartridge slot parallel to the Pi. I'm thinking hanging over the edge, unless it can be well supported above the Pi. Is this a Pi4?
• Allow for both SOIC (installed, easy to disable) or DIP (easy to change out) LVC245 chip.
• Decent amount of space/contacts for testing/probing of each line (and labeled).
• Switch for the 5V, labeled on/off.

[marauder666]

Need to get a 245 and then I can rig something up using a stripped jr pcb

[Kroko]

4 hours ago, Al_Nafuur said:

Has anyone so far setup a breadboard and a Pi to test?

 

My breadboard setup (or the Pi) is misbehaving since yesterday and I cannot get consistent reads (even when dumping a simple 2K cart)

I ordered a Pi 3B+ and a few 245 but it will take some time before stuff arrives and I have time to set it up...

[Albert]

13 hours ago, Al_Nafuur said:

@Albert OK

Thank you, I have now moved the thread. 

 

 ..Al

[+MarcoJ]

5 hours ago, Al_Nafuur said:

Has anyone so far setup a breadboard and a Pi to test?

Mine is due early next week. 

[+5-11under]

I ordered 10 boards. I went with lowest shipping price, so these won't arrive for 3-6 weeks.

I also didn't follow most of my design plans... if changes are required, I'll hack it, or just get new boards.

If they work, I'll let you know.

 

[+Al_Nafuur]

(re)tested on the PlusCart with the new build:

 

• DPC: Activision Pitfall II OK
• F8SC: Atari Defender OK
• F6SC: Atari Dig Dug not working
• CV: CommaVid Video Life running but half of the RAM is not written correctly?
• F0: DynaCom Mega Boy OK
• E0: Parker Bros Super Cobra OK

• E7: M-Network Burgertime not working

 

 

[+Al_Nafuur]

On 9/16/2023 at 4:09 AM, 5-11under said:

I ordered 10 boards. I went with lowest shipping price, so these won't arrive for 3-6 weeks.

I also didn't follow most of my design plans... if changes are required, I'll hack it, or just get new boards.

If they work, I'll let you know.

It is too early for production boards, but for testing they will be of great use. Testing on a breadboard is a real pain, you always have to take care for the cables and some cartridges tear out the edge connector when you remove them.

 

[+Al_Nafuur]

  

Tested F4SC Aardvark Demo on the PlusCart:

 

 

[+rbairos]

How does Pitfall2 on the PlusCart on your bus emulator work?
Who is doing the DPC bankswitching?

[Thomas Jentzsch]

6 hours ago, Al_Nafuur said:

 Tested F4SC Aardvark Demo on the PlusCart:

There seems to be a problem with cart RAM access. The green underground "barriers" shouldn't be there.

 

But only the low 3 bits of the playfield are affected. The data (all 8 bits) is loaded from cart RAM, pushed onto the stack and loaded from there for display.

[JetSetIlly]

7 minutes ago, Thomas Jentzsch said:

There seems to be a problem with cart RAM access. The green underground "barriers" shouldn't be there.

 

But only the low 3 bits of the playfield are affected. The data (all 8 bits) is loaded from cart RAM, pushed onto the stack and loaded from there for display.

 

The icon after the HiScore value on the menu screen doesn't like correct either.

 

[Thomas Jentzsch]

18 minutes ago, JetSetIlly said:

The icon after the HiScore value on the menu screen doesn't like correct either.

 

True. And with a high score of 0 it should look like this:

[+Al_Nafuur]

5 hours ago, rbairos said:

How does Pitfall2 on the PlusCart on your bus emulator work?
Who is doing the DPC bankswitching?

bankswitching always happens inside the cartridge, here the PlusCart.

 

[+Al_Nafuur]

42 minutes ago, Thomas Jentzsch said:

There seems to be a problem with cart RAM access. The green underground "barriers" shouldn't be there.

 

But only the low 3 bits of the playfield are affected. The data (all 8 bits) is loaded from cart RAM, pushed onto the stack and loaded from there for display.

It seems like the first 3 bits are already pulled high when the cart reads the value on the databus. There is a similar pattern on the Video Life (CV banking) game.

 

So we might need a few ns more delay before we switch the data bus back to read, or we have an issue with setting these three GPIO pins.

[Thomas Jentzsch]

2 minutes ago, Al_Nafuur said:

It seems like the first 3 bits are already pulled high when the cart reads the value on the databus. There is a similar pattern on the Video Life (CV banking) game.

 

So we might need a few ns more delay before we switch the data bus back to read, or we have an issue with setting these three GPIO pins.

Does the speed of the RAM play a role for the required delay? E.g. we know that SC RAM is too slow for code execution. While CV RAM is fine. 

[+Al_Nafuur]

46 minutes ago, Thomas Jentzsch said:

Does the speed of the RAM play a role for the required delay? E.g. we know that SC RAM is too slow for code execution. While CV RAM is fine. 

The real cartridges with RAM are doing the writes (or read from their point of view) different than the PlusCart/UnoCart are doing. The cartridges are waiting (or need) ~500ns before they read the value on the data bus. The 6502 is setting the data ~415ns after he changed the address and holds it for about ~350ns. The PlusCart/UnoCart are constantly reading the data bus until the address bus changes again and then take the last data read before the address change.

 

I am not sure but the real cartridges might have a much better chance to work with our setup.

 

The PlusCart/UnoCart approach works fine with a real 6502, but maybe we should use something like nanosleep or cpu tick counts on the PlusCart firmware to wait ~500ns and read the data bus earlier.

 

https://stackoverflow.com/questions/13379220/generating-nanosecond-delay-in-c-on-stm32

[marauder666]

Hopefully something will be running by the weekend.

Power switch is now wired from 5V on the GPIO header.

No 245 arrived yet.

 

Stella up and running on the pi.

Edited September 19, 2023 by marauder666

[marauder666]

some development.  Maybe have something wired up tomorrow.

Lots of checking to do on that IDE cable.

 

 

 

Edited September 22, 2023 by marauder666

[+MarcoJ]

42 minutes ago, marauder666 said:

Some development.  Maybe have something wired up tomorrow.

Nice progress @marauder666. 

 

I’m also using a console, a modded Flashback 2. Going to hook up the cart slot tomorrow. I’m using a hat prototype board to sit on top of the raspberry pi. Just finished it tonight. 

 

[marauder666]

Couldn't resist.

But it will have to wait until tomorrow to be checked out before the pi gets connected.

 

I would have used a DIP IC, but one here in the UK was same price as 6 SMD and 2 adapter boards