I'm trying to understand exactly what goes on inside the Jaguar's controller. My knowledge of electronics is practically zero, and I'm running into a few head-scratchy moments.
From a logical perspective, things are fairly simple, except for the use of negative logic throughout. There are 4 outputs from the Jaguar, which connect to the buttons (via diodes to prevent cross connections) in a 4x6 matrix, which then flow to the 6 inputs on the Jaguar. The Jaguar enables each of the 4 pins in turn, reads the 6 pins and caches the result in the right row and moves onto the next of the 4 pins. Simple, relatively anyway.
But when we drop down a level and look at the electronics, things get more than a little confusing for me. The 4 outputs from the Jaguar (which are enabled by driving them low) are connected to the inputs of an LS244 / HC244 type octal 3-state line driver. Only 6 of it's 8 lines are used, and the output enable pins are wired always on, which as I understand it, means that the driver will either drive the lines high or drive them low. What is confusing me is the arrangement of the diodes and pull up resistors on the input side of the LS244. My best guess is that the pull up resistor keeps the line high unless the Jag is driving the line low and the corresponding button is pressed, but I'm not entirely sure I understand how.
Also I think there's an error on Steven Moss' diagram: pins 14 and 6 seem to be the wrong way round.
Full Version: Hardware: Understanding the Jaguar Controller
CITATION(Tyr of the Arcana @ 16 Jul 2010, 21:40) 
Only 6 of it's 8 lines are used, and the output enable pins are wired always on, which as I understand it, means that the driver will either drive the lines high or drive them low.
Correct.CITATION(Tyr of the Arcana @ 16 Jul 2010, 21:40)
What is confusing me is the arrangement of the diodes and pull up resistors on the input side of the LS244. My best guess is that the pull up resistor keeps the line high unless the Jag is driving the line low and the corresponding button is pressed, but I'm not entirely sure I understand how.
Correct. It's called wired-AND diode logic.CITATION(Tyr of the Arcana @ 16 Jul 2010, 21:40)
Also I think there's an error on Steven Moss' diagram: pins 14 and 6 seem to be the wrong way round.
Yes, there's an error in the PDF : pin 6 and 14 of the 74HC244 have been swapped.You can use the description in the official docs and the pad schematic from the Jaguar FAQ if you prefer, as they're easier to read :
Click to view attachment
CODE
Q: What's the wiring schematic for the Jaguar controller?
A: Uwe Roeger (uwer@aragon.bb.bawue.de) reverse-engineered the Jaguar
controller port and dissected a Jaguar controller to provide the
following circuit diagram:
Padport 4 Padport 3 Padport 2 Padport 1
(yellow) (orange) (red) (brown) 74HC244
| | | | ______
| | | | R1 4k7 | |
| | | | | | | Padport 6
Pause -------|----------|----------|----------+----- 2| -|)- |18- (blue)
| | | | | |
| +---|------+---|------+---|------+ R2 4k7 | |
| | | | | | | | | | | Padport 10
"A"--|<-+ "B"--|<-+ "C"--|<-+ Opt -|<-+---+----- 4| -|)- |16- (black)
| | | | | |
| +---|------+---|------+---|------+ R3 4k7 | |
| | | | | | | | | | | Padport 11
Right-|<-+ "1"--|<-+ "2"--|<-+ "3"--|<-+---+----- 6| -|)- |14- (grey)
| | | | | |
| +---|------+---|------+---|------+ R4 4k7 | |
| | | | | | | | | | | Padport 12
Left -|<-+ "4"--|<-+ "5"--|<-+ "6"--|<-+---+----- 8| -|)- |12- (l.blue)
| | | | | |
| +---|------+---|------+---|------+ R5 4k7 | |
| | | | | | | | | | | Padport 13
Down -|<-+ "7"--|<-+ "8"--|<-+ "9"--|<-+---+-----11| -|)- |9-- (pink)
| | | | | |
| +---|------+---|------+---|------+ R6 4k7 | |
| | | | | | | | | | | Padport 14
Up --|<-+ "*"--|<-+ "0"--|<-+ "#"--|<-+---+-----13| -|)- |7-- (white)
|______|
Padport 9: Ground (violet) -- Pin 1,10,15,17,19 on 74HC244
Padport 7: +5 VDC (green) -- Pin 20 on 74HC244
SYMBOL KEY
==========
--|<-- 1N4148 Diode
+ Wire connexion
Rx 4k7 Standard resistor, 4700 Ohms, .25 Watts (all resistors are
pull-ups; i.e. tied to +5VDC on one end)
Padport numbers correspond to those on a standard 15-pin SUB-D plug. The
colors of the wires may be different in other versions of the controller.
A: Uwe Roeger (uwer@aragon.bb.bawue.de) reverse-engineered the Jaguar
controller port and dissected a Jaguar controller to provide the
following circuit diagram:
Padport 4 Padport 3 Padport 2 Padport 1
(yellow) (orange) (red) (brown) 74HC244
| | | | ______
| | | | R1 4k7 | |
| | | | | | | Padport 6
Pause -------|----------|----------|----------+----- 2| -|)- |18- (blue)
| | | | | |
| +---|------+---|------+---|------+ R2 4k7 | |
| | | | | | | | | | | Padport 10
"A"--|<-+ "B"--|<-+ "C"--|<-+ Opt -|<-+---+----- 4| -|)- |16- (black)
| | | | | |
| +---|------+---|------+---|------+ R3 4k7 | |
| | | | | | | | | | | Padport 11
Right-|<-+ "1"--|<-+ "2"--|<-+ "3"--|<-+---+----- 6| -|)- |14- (grey)
| | | | | |
| +---|------+---|------+---|------+ R4 4k7 | |
| | | | | | | | | | | Padport 12
Left -|<-+ "4"--|<-+ "5"--|<-+ "6"--|<-+---+----- 8| -|)- |12- (l.blue)
| | | | | |
| +---|------+---|------+---|------+ R5 4k7 | |
| | | | | | | | | | | Padport 13
Down -|<-+ "7"--|<-+ "8"--|<-+ "9"--|<-+---+-----11| -|)- |9-- (pink)
| | | | | |
| +---|------+---|------+---|------+ R6 4k7 | |
| | | | | | | | | | | Padport 14
Up --|<-+ "*"--|<-+ "0"--|<-+ "#"--|<-+---+-----13| -|)- |7-- (white)
|______|
Padport 9: Ground (violet) -- Pin 1,10,15,17,19 on 74HC244
Padport 7: +5 VDC (green) -- Pin 20 on 74HC244
SYMBOL KEY
==========
--|<-- 1N4148 Diode
+ Wire connexion
Rx 4k7 Standard resistor, 4700 Ohms, .25 Watts (all resistors are
pull-ups; i.e. tied to +5VDC on one end)
Padport numbers correspond to those on a standard 15-pin SUB-D plug. The
colors of the wires may be different in other versions of the controller.
Thank you.
Next question: Would an HC365 or 367 work in place of the LS244? It looks to be similar enough to me and has a nicer arrangement of input and output pins, but I'm still a noob when it comes to electronics.
Next question: Would an HC365 or 367 work in place of the LS244? It looks to be similar enough to me and has a nicer arrangement of input and output pins, but I'm still a noob when it comes to electronics.
Actually scrub that, its pinout is still annoying. Does anyone know of a driver with all it's input (a pins) on one side, and all its outputs (y pins) on the other?
The 74HC245 fits the bill.
QUOTE (Zerosquare @ 17 Jul 2010, 17:26)
The 74HC245 fits the bill.
Mr Zerosquare sir, I think I love you! Thanks! This will make things so much simpler.
CITATION(Tyr of the Arcana @ 17 Jul 2010, 18:38)
Mr Zerosquare sir, I think I love you! Thanks!
Hum, I... like you too 
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.