help with 3-channel analog switch

[Swami]

Can anyone explain to me how to wire up a CD74HC4053 3-channel analog switch (like the one in the Seagull 78) or similar to create the following effect (numbers are pins in a DB9 controller interface):

Basically, when you close the switch between 6 and 8 at the top, it "ends the connection" with 8 electronically at the middle switch and allows the "open" connection between 5 and 6 at the bottom switch to be "closed" (low resistance/gain continuity). There's also an external +5V and true GND to power the IC where needed. It's for Amiga to ColecoVision, so,

 

1. Top section is controller and bottom section is an adapter to the console controller port.

 

2. at the bottom, 5 and 8 are both hi/low potential GND and 6 is active, but the closing of top switch has to break 6 to 8 and connect 5 to 6, and reverse when switch is open.

 

3. Actually, though, that middle switch can always be "no continuity" if that helps (if even possible). The real necessity is the bottom switch is always the opposite of the top one, the middle one is open when the bottom is closed (or always) and the top one is the only one you can touch.

 

[+Stephen Moss]

It is not exactly clear what you want as...

You have two sixes and two eights, first is it unclear if they are the same 6 & 8 or different pairs 6 & 8 and whether or not they refer to controller cable pin, console port pins or the 74HC4053 pins.

The in one image connection are label A and the other B.

Perhaps if you just called you connection point A, B, C, D or 1 , 2, 3, & 4 and then indicates the different options you wanted in may be easier to under stand what you want, i.e.

Option 1) 1 connected to 2

Option 2) 1 connected to 4

Option 3) 3 connected to 1 & 4

 

Depending on what exactly it is you want the CD74HC4053 may not be the best device is the device you want as it is more or a multiplexer than a switch, the CD4016BE may be better.

[Swami]

5 hours ago, Stephen Moss said:

It is not exactly clear what you want as...

You have two sixes and two eights, first is it unclear if they are the same 6 & 8 or different pairs 6 & 8 and whether or not they refer to controller cable pin, console port pins or the 74HC4053 pins.

The in one image connection are label A and the other B.

Perhaps if you just called you connection point A, B, C, D or 1 , 2, 3, & 4 and then indicates the different options you wanted in may be easier to under stand what you want, i.e.

Option 1) 1 connected to 2

Option 2) 1 connected to 4

Option 3) 3 connected to 1 & 4

 

Depending on what exactly it is you want the CD74HC4053 may not be the best device is the device you want as it is more or a multiplexer than a switch, the CD4016BE may be better.

The top are pins 6 and 8 of the Amiga mouse DB9 controller cord. The bottom is pins 5, 6 an 8 of the Colecovision DB9 controller port. The left diagram shows where continuity should be when button is not pushed and right diagram shows where continuity should be when button is pushed.

 

You cannot mod the Amiga controller. The adapter is meant to be plug and play with an Amiga mouse. (Don't worry about the quadrature. I've taken care of that.) This is about right mouse button (pin 9 to pin 8 on mouse) becoming fire 1  (pin 6 and 8 on Colecovision, which is easy) - and left mouse button (pin 6 to 8 on mouse) becoming fire 2, which needs to connect pins 5 and 6 on the ColecoVision, with neither having continuity to pin 8 (or fire 1 with fire).

 

When I push the button at the top that connects pins 6 and 8 of the controller cord, I want pins 6 and 8 to break continuity somewhere else along the connection between pin 6 on the Colecovision controller port and pin 8 of this controller port. simultaneously, I want pin 5 and 6 to be connected. It's also okay if pins 5 and 6 on the Colecovision controller port never have continuity with pin 8 on this port.

 

When the button on top is released the opposite happens. If a discontinuity between pins 6 and 8 on the ColecoVision controller port can always exist and connecting the lines between .

 

A and B just refer to each “switch” being at time A or time B. Time A when top Switch is open and time B when it is closed. 

 

As I said, this is vaguely similar to the Seagull 78 adapter where you push fire 1 on the genesis controller which connects pins 8 and 6 on the controller and it connects pins 5, 6 and 8 on the atari 7800, but what I want is more complex. 

 

From what I understand, both of the ICs in the previous post are mux chips. The one you mention has an additional fourth channel vs the 2-channel. I can see where that may be helpful, although I don’t understand the technology well. 

[Swami]

I should add I cannot just run pin 6 on the controller cord to pin 6 and pin 8 to pin 5, since the 4 direction pins 1-4 on the controller need to be grounded to pin 8, so, pin 8 on the controller cord must go to pin 8 on the console controller port. 

 

I’ll try to draw something more thorough at some point. 

[Swami]

11 hours ago, Stephen Moss said:

It is not exactly clear what you want as...

You have two sixes and two eights, first is it unclear if they are the same 6 & 8 or different pairs 6 & 8 and whether or not they refer to controller cable pin, console port pins or the 74HC4053 pins.

The in one image connection are label A and the other B.

Perhaps if you just called you connection point A, B, C, D or 1 , 2, 3, & 4 and then indicates the different options you wanted in may be easier to under stand what you want, i.e.

Option 1) 1 connected to 2

Option 2) 1 connected to 4

Option 3) 3 connected to 1 & 4

 

Depending on what exactly it is you want the CD74HC4053 may not be the best device is the device you want as it is more or a multiplexer than a switch, the CD4016BE may be better.

I think I may have it. I may need two CD4016BE chips, in fact, so both buttons work at the same time. I don’t know if multiple control points can be high at the same time. 

[+Stephen Moss]

I think I have a solution, the 4016BE on resistance it a little high, it will probably be OK but you might have to increase the resistor values from 4K7 to 5K6 just to ensure the voltage drops low enough to turn the switches off. I recommend using the 74HC4016 instead if you can get it as it has a much lower on resistance.

 

I am assuming your pin 8 to 9 comment means that as the Amiga is essentially an ST clone the controller inputs are the same and are active low (think I forgot to tie the mouse and Coleco grounds together in the diagram). So with the Enable pins being active high we need to invert the pull to ground to a pull to 5V which is what U1b and U1d do (you might want to change which switch does what for a better PCB layout), I will describe how relative to U1b...

 

When the Right mouse button is not pressed the the Enable pin (E) is pulled high via R4 turning the switch on and connecting the bottom end of R5 to ground, turning U1c off.

When the Right mouse button is pressed it pulls the Enable pin to ground, the bottom end of R5 is not longer connected to ground and pulls the Enable pin of U1c high connecting Coleco controller port pins 6 to 8 - making the right mouse button Fire 1.

 

The left mouse button works similarly connecting Coleco pins 5 & 6 (U1a), making it Fire 2. It is also connected to the bottom end of R5 which pulls it to ground, turning off U1C preventing 6 & 5 also being connected to 8. So...

Right Mouse Button only = Fire 1 (Coleco port pins 6 & 8 connected)

Left Mouse Button only = Fire 2 (Coleco port pins 5 & 6 connected)

Both Mouse button pressed at the same time =  Fire 2 (Coleco port pins 5 & 6 connected) 

 

Well at least theoretically, if both mouse buttons are pressed virtually simultaneously, the speed with which the switches react could result in brief period where Coleco pins 5, 6 & 8 are connected together. To prevent that you would have to add some form of timing/synchronisation circuitry. Personally I would use an 8 pin PIC, they are small, cheap and you can program in any delay time you want within reason.

 

You may notice R3 is missing, I had it in I but removed it as I no longer needed it.