- ITC Chronicles - :- Stories from the Ivory Tower Collections

Nice mod and very clean job!

A couple of notes:

1- You don't need to wire the second port, but you cannot just leave the inputs of a logic gate unconnected, else they'll show erratic behavior, electrical noise and increased power consumption (especially with HC/HCT family ICs like in this case).

Simply tie "2U" and "2D" inputs on the mod board to +5V if you don't want the pause function for the second port.

 

2- Consider adding a switch to disable the mod (e.g. break the connection between the "PB" output of the board and RIOT pin 21). Else, some controllers such as driving controllers and trackballs will trigger the pause (or B&W switch in 2600 mode) function.

This can also happen when a game uses the ports as outputs: for example, pins 1 and 2 ("up" and "down" in a joystick) are used to interface with an Atarivox, and the RIOT outputs can be set simultaneously LOW by the code while trying to communicate with the device, even if nothing is plugged in the port, and that again will trigger the pause/B&W switch.

 

Given the number of different controllers and devices (and the new ones that the homebrew community keeps developing), and the great flexibility of the 2600/7800 controller ports I/O pins, there isn't a combination  that is really "impossible". There will always be some game or device that will trigger it, so you need to be able to disable it if needed.

Edited March 30 by alex_79

8 hours ago, alex_79 said:

Nice mod and very clean job!

A couple of notes:

1- You don't need to wire the second port, but you cannot just leave the inputs of a logic gate unconnected, else they'll show erratic behavior, electrical noise and increased power consumption (especially with HC/HCT family ICs like in this case).

Simply tie "2U" and "2D" inputs on the mod board to +5V if you don't want the pause function for the second port.

 

2- Consider adding a switch to disable the mod (e.g. break the connection between the "PB" output of the board and RIOT pin 21). Else, some controllers such as driving controllers and trackballs will trigger the pause (or B&W switch in 2600 mode) function.

This can also happen when a game uses the ports as outputs: for example, pins 1 and 2 ("up" and "down" in a joystick) are used to interface with an Atarivox, and the RIOT outputs can be set simultaneously LOW by the code while trying to communicate with the device, even if nothing is plugged in the port, and that again will trigger the pause/B&W switch.

 

Given the number of different controllers and devices (and the new ones that the homebrew community keeps developing), and the great flexibility of the 2600/7800 controller ports I/O pins, there isn't a combination  that is really "impossible". There will always be some game or device that will trigger it, so you need to be able to disable it if needed.

I wasn't aware of the AtariVox functions being affected by this? I will have to give that try as one of the other many mods on my 7800 is an Audio input jack that I plug my AtariVox into to be mixed within the console and come out with the rest of the audio so I don't have to connect it to separate external speakers.

But the reason I use Up+Dn is not just because this pause kit also does, but because I originally years ago was using the Left+right combo and the Harmony cart did NOT care for it at all. I do have a diode pair inside my controllers to isolate the signals from each other independently, but the actual SMS kits only use a pair of 220ohm resistors off the inputs.

As for the driving controller and trackballs? I own them, but I never use them on my 7800 as I just don't play any games that use them.

 

3 hours ago, CrossBow said:

I wasn't aware of the AtariVox functions being affected by this?

The AtariVox will work just fine (the gate input are high impedance and do not affect the levels of the pins), but the pause mod can be triggered while the Atari communicates with the device. Whether this causes issues or not depends on the specific game. The fact that current games work fine doesn't exclude the possibility that future ones might have issues.

 

The SNES2Atari adapter supported, for example, by "Attack of the PETSCII Robots" for the 7800, uses pins 1 and 2 to send the clock and latch signal to the SNES controller. The Savekey uses pins 3 and 4 for the I2C serial data and clock protocol. The "Compumate" for the 2600 uses pins 1-4 on both ports for the bankswitching of the Computer ROM.

There are some roms that use the ports to communicate with a computer serial port, or to drive external devices, and it's possible, for example, to use them to connect two consoles and play multiplayer games that way...

 

 

The 2600RGB mod uses a similar method of "impossible combination of inputs" to add an extra SWITCH on the controller to allow for remote RESET and SELECT switches, as well as an hardware PAUSE (it halts the CPU) and a PALETTE select function.

That proved to be incompatible with the mentioned trackball games (which caused disappointment to the unaware customers), but also in other cases which are less obvious:

e.g. "Track and Field" is unplayable (with a standard joystick, not only with the "Track and Field" controller that allows to press left and right simultaneously) if you have a RGB mod with the extra function wired to the controller port. And doesn't matter if you actually have the extra switch installed on the joystick.  That's because, for whatever reason, the code in the game briefly pulses pins 1-4 LOW in both ports on each frame!

 

My point is that the pins on the controller ports are general purpose Input/Output ones, and the game code has full control over them. Not only different controllers can pull up/down different combination of inputs, but the code itself can drive them directly, even when nothing is connected to the port, and the pause mod cannot tell the difference. The possibilities are infinite, and new games and controller/devices keeps being developed. That's why I suggest to have a switch to disable the function: if you ever encounter a game (or controller or device) that conflicts with it, you can just temporarily turn it off.

3 hours ago, alex_79 said:

The AtariVox will work just fine (the gate input are high impedance and do not affect the levels of the pins), but the pause mod can be triggered while the Atari communicates with the device. Whether this causes issues or not depends on the specific game. The fact that current games work fine doesn't exclude the possibility that future ones might have issues.

 

The SNES2Atari adapter supported, for example, by "Attack of the PETSCII Robots" for the 7800, uses pins 1 and 2 to send the clock and latch signal to the SNES controller. The Savekey uses pins 3 and 4 for the I2C serial data and clock protocol. The "Compumate" for the 2600 uses pins 1-4 on both ports for the bankswitching of the Computer ROM.

There are some roms that use the ports to communicate with a computer serial port, or to drive external devices, and it's possible, for example, to use them to connect two consoles and play multiplayer games that way...

 

 

The 2600RGB mod uses a similar method of "impossible combination of inputs" to add an extra SWITCH on the controller to allow for remote RESET and SELECT switches, as well as an hardware PAUSE (it halts the CPU) and a PALETTE select function.

That proved to be incompatible with the mentioned trackball games (which caused disappointment to the unaware customers), but also in other cases which are less obvious:

e.g. "Track and Field" is unplayable (with a standard joystick, not only with the "Track and Field" controller that allows to press left and right simultaneously) if you have a RGB mod with the extra function wired to the controller port. And doesn't matter if you actually have the extra switch installed on the joystick.  That's because, for whatever reason, the code in the game briefly pulses pins 1-4 LOW in both ports on each frame!

 

My point is that the pins on the controller ports are general purpose Input/Output ones, and the game code has full control over them. Not only different controllers can pull up/down different combination of inputs, but the code itself can drive them directly, even when nothing is connected to the port, and the pause mod cannot tell the difference. The possibilities are infinite, and new games and controller/devices keeps being developed. That's why I suggest to have a switch to disable the function: if you ever encounter a game (or controller or device) that conflicts with it, you can just temporarily turn it off.

Wow, all excellent info! Thanks! Well in my case, I believe I still have my channel select switch in place on my console and since I removed the RF from it over a year ago to add in the audio input jack, seems as good an option for making it useful again as possible? I will reform the leads on it a bit so I can try and move it further back a tiny bit to make it easier to reach.

On 3/31/2024 at 5:08 AM, alex_79 said:

The AtariVox will work just fine (the gate input are high impedance and do not affect the levels of the pins), but the pause mod can be triggered while the Atari communicates with the device. Whether this causes issues or not depends on the specific game. The fact that current games work fine doesn't exclude the possibility that future ones might have issues.

 

The SNES2Atari adapter supported, for example, by "Attack of the PETSCII Robots" for the 7800, uses pins 1 and 2 to send the clock and latch signal to the SNES controller. The Savekey uses pins 3 and 4 for the I2C serial data and clock protocol. The "Compumate" for the 2600 uses pins 1-4 on both ports for the bankswitching of the Computer ROM.

There are some roms that use the ports to communicate with a computer serial port, or to drive external devices, and it's possible, for example, to use them to connect two consoles and play multiplayer games that way...

 

 

The 2600RGB mod uses a similar method of "impossible combination of inputs" to add an extra SWITCH on the controller to allow for remote RESET and SELECT switches, as well as an hardware PAUSE (it halts the CPU) and a PALETTE select function.

That proved to be incompatible with the mentioned trackball games (which caused disappointment to the unaware customers), but also in other cases which are less obvious:

e.g. "Track and Field" is unplayable (with a standard joystick, not only with the "Track and Field" controller that allows to press left and right simultaneously) if you have a RGB mod with the extra function wired to the controller port. And doesn't matter if you actually have the extra switch installed on the joystick.  That's because, for whatever reason, the code in the game briefly pulses pins 1-4 LOW in both ports on each frame!

 

My point is that the pins on the controller ports are general purpose Input/Output ones, and the game code has full control over them. Not only different controllers can pull up/down different combination of inputs, but the code itself can drive them directly, even when nothing is connected to the port, and the pause mod cannot tell the difference. The possibilities are infinite, and new games and controller/devices keeps being developed. That's why I suggest to have a switch to disable the function: if you ever encounter a game (or controller or device) that conflicts with it, you can just temporarily turn it off.

Alex, I tested my Avox+ and SNES2Atari adapter and didn't encounter any issues on my primary 7800. But, to be on the safe side. I did cut all the traces to the channel select switch and run new wire from the pause board and back to the RIOT to a slightly modified channel select switch to allow me to turn that pause line on/off just in case. It would be better if I could find switches just like those used originally but with longer switches so they can poke through the back of the shell better. Currently I've been reforming the pins on the bottom and using the front set of vias closest to the edge of the board to mount standard difficult/channel select switches. I did it on both my main 7800 and on an extra in the lab that I actually sold last night in a record 20min time.

Anyway, thank you again for that suggestion!