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2600 pause mod on a 7800?


atariguy1021

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The 6502 in the 7800 is different to the 6507 in the 2600 in various ways other than the obvious.

 

The 2600 pause method of holding the clock is already implemented in the Sally 6502 of the 7800 (since it's shared with the computer range) - the /HALT pin stops the CPU so that Antic or Maria can do DMA for graphics.

 

It'd likely be possible to do a variant that holds /HALT on the 7800 - chances are it might cause crashes or weird behaviour in 7800 mode but would probably work "normally" in 2600 mode.

Of course the same blank/rolling screen situation would apply but there's not much way around it.

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  • 4 weeks later...

So in theory it'll work fine as long as you don't use the pause while playing 7800 games?

 

Yes, and it's much easier, all you need is a toggle switch and 3 wires. Lift out the RDY pin (#2) (or cut it low and bend it up), connect it to the center of the switch, then connect one side of the switch to the point where the original pin made connection with the PCB. Finally connect the other side of the switch to GND. That should do it, albeit, I have not tried it.

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  • 3 years later...
  • 3 weeks later...

Anyone put the pause mod a 4 switch sunnyvale? The one that was made in the USA has a different motherboard and the resistor placement is way different versus the tiwanese 4 switch revision in the guide. Here are some pics to show you the differences. Said resistor you are to remove is not present on the sunnyvale revision and I've no clue where it is. I've attached photo's of the resistor banks which include one of the same value that is to be removed.

 

pic from the guide for 4 switch:

post-7107-0-62859900-1463342630_thumb.jpg

 

The board inside a sunnyvale 4 switch:

post-7107-0-24510100-1463342782_thumb.jpg

 

Other spots on the board with resistors of the same value:

post-7107-0-80628200-1463342783_thumb.jpgpost-7107-0-62231600-1463342784_thumb.jpg

 

:)

 

 

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Anyone put the pause mod a 4 switch sunnyvale? The one that was made in the USA has a different motherboard and the resistor placement is way different versus the tiwanese 4 switch revision in the guide. Here are some pics to show you the differences. Said resistor you are to remove is not present on the sunnyvale revision and I've no clue where it is. I've attached photo's of the resistor banks which include one of the same value that is to be removed.

 

pic from the guide for 4 switch:

attachicon.giffgrdgf.JPG

 

The board inside a sunnyvale 4 switch:

attachicon.gifDSCF6860.JPG

 

Other spots on the board with resistors of the same value:

attachicon.gifDSCF6861.JPGattachicon.gifDSCF6862.JPG

 

:)

 

 

 

Basically, the pause mod just needs to intercept the read/write signals between the 6507 and TIA. If you can't identify the trace - just lift pin 3 of the TIA, and solder it to the mod board. The rest is the same.

 

Also, it doesn't matter where you grab +5V's and GND. It just needs to be connected to 5 volts, and a ground connection. (Something to note is that using the exposed, metal sides of the PCB is a pretty awful place for ground. Don't use it unless there is literally no other place to put a ground connection. A good place for ground on ANY 2600 or 2600 clone is Negative on the main cap)

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K I removed that resistor and it made no difference. Looks like you don't have to remove anything with the USA 4 switch pcb. Just have to make sure the trace is cut to tia 3 and you are good to go. I have it installed and working perfectly without removing any resistors at all.

Edited by Shawn
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  • 4 years later...
On 2/3/2013 at 7:23 PM, CPUWIZ said:

 

Yes, and it's much easier, all you need is a toggle switch and 3 wires. Lift out the RDY pin (#2) (or cut it low and bend it up), connect it to the center of the switch, then connect one side of the switch to the point where the original pin made connection with the PCB. Finally connect the other side of the switch to GND. That should do it, albeit, I have not tried it.

So I actually tried this last night on my test unit 7800 and the results? Well...not quite good I'm afraid. Here is what would happen..

 

I wired up using a switch similar to the difficulty switches or channel select switch found on the 7800 as I have plenty of those on hand. I removed pin 2 off the 6502 from the board and attached it to the center of the switch. I then attached the ground to one side and a wire from the other side to the RDY line on the board where pin 2 was previously. Put in the Harmony and turned on color cycle mode and then flipped the switch. Screen went black as I would have expected. I flip the switch back and the Harmony came back up in the menu and still color cycling as before.

 

I then proceeded to test out several games both through the harmony and actual carts. The results were that it actually doesn't work as we would like. If you flip the switch and then flip it back within a few seconds, then in most cases, the games will come back up like nothing happened. But in most cases and especially if you left it in the pause state for about 20 or 30 seconds or longer. Then when you flipped the switch back, the system would just stay at a black screen and never restore. So it seems that just turning the halt on/off like this doesn't really work for the 2600 games. 7800 games would only flicker for a sec when you used it but otherwise didn't seem affected by it at all. 

 

So at least in trying to test out CPU's idea it kinda works but not for long term pausing of a game and in many cases the games would immediately bug out similar to when you tilt the carts while powered one when you used it. Could be something where a cap or something is needed to debounce the signal maybe?

 

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