Home
JAQForum Ver 24.01
Log In or Join  
Active Topics
Local Time 11:42 09 Oct 2024 Privacy Policy
Jump to

Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.

Forum Index : Microcontroller and PC projects : wiring up a mouse to the CMM2

Author Message
johngill
Newbie

Joined: 22/09/2020
Location: United Kingdom
Posts: 35
Posted: 02:00pm 15 Feb 2021
Copy link to clipboard 
Print this post

Hi all,

I'd like to have a crack at attaching a PS2 mouse to my CMM2.

My soldering skills are adequate, but my electronics understanding is, limited, shall we say!

I've found a pin-out of the PS2 connector:



I understand the I/O connector pin out on page 10 of the user guide, and I need to wire up the appropriate pins to the PS2 connector as per the instructions in the readme file on the latest firmware beta download.

"To make the connection the MOUSE clock line is connected to pin 33 of the CMM2 and the MOUSE data to pin 32. Both lines MUST be pulled up to 5V with 4K7 resistors"

I can understand a circuit diagram, but I don't understand electronics enough to know how the sentence "both lines MUST be pulled up to 5V with 4k7 resistors" translates into a circuit diagram - please can anyone help me?

Also, there is a VCC pin on the PS2 connector, which I'm assuming should be connected to +ve power, but there are 2 different voltages on the I/O connector, 3.3V and 5V - I'm guessing I should be using the 5V - is that right?

Many thanks in advance
 
matherp
Guru

Joined: 11/12/2012
Location: United Kingdom
Posts: 8950
Posted: 02:06pm 15 Feb 2021
Copy link to clipboard 
Print this post

  Quote  I can understand a circuit diagram, but I don't understand electronics enough to know how the sentence "both lines MUST be pulled up to 5V with 4k7 resistors" translates into a circuit diagram - please can anyone help me?


Connect a 4K7 resistor between CLOCK and VCC and another between DATA and VCC

  Quote  I'm guessing I should be using the 5V - is that right?


Yes
 
RetroJoe

Senior Member

Joined: 06/08/2020
Location: Canada
Posts: 290
Posted: 02:45pm 15 Feb 2021
Copy link to clipboard 
Print this post

@johngill, please have a look here

It should be obvious from the schematic  why they are called pull "up" resistors :)

P.S. is your forum name a Star Trek reference ?
Edited 2021-02-16 00:46 by RetroJoe
Enjoy Every Sandwich / Joe P.
 
RetroJoe

Senior Member

Joined: 06/08/2020
Location: Canada
Posts: 290
Posted: 02:55pm 15 Feb 2021
Copy link to clipboard 
Print this post

These pinouts are unlikely to change, so for future reference (and possible inclusion in the CMM2 docs?), here 'tis the mouse circuit in bitmapped goodness. But, a "live" cloud-based repo of CMM2 circuits contributed by the community remains intriguing :)


Enjoy Every Sandwich / Joe P.
 
phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 2029
Posted: 01:12am 16 Feb 2021
Copy link to clipboard 
Print this post

The top photo has Vcc and Gnd reversed, compared to my MM+ which has ben in use for several years without problem. Please doublecheck this before powering up.

Checked further, Vcc and Gnd should be swapped or the keyboard may be damaged.
Edited 2021-02-16 16:04 by phil99
 
paceman
Guru

Joined: 07/10/2011
Location: Australia
Posts: 1329
Posted: 11:44am 16 Feb 2021
Copy link to clipboard 
Print this post

I agree that @phill99's post above is correct - the diagram at the top has 5v and Gnd reversed.

Greg
 
johngill
Newbie

Joined: 22/09/2020
Location: United Kingdom
Posts: 35
Posted: 02:17pm 16 Feb 2021
Copy link to clipboard 
Print this post

  phil99 said  The top photo has Vcc and Gnd reversed, compared to my MM+ which has ben in use for several years without problem. Please doublecheck this before powering up.

Checked further, Vcc and Gnd should be swapped or the keyboard may be damaged.


Many thanks for this - much appreciated - seems one can't rely on google images for good electronics tips - who'd have thought?!    
 
johngill
Newbie

Joined: 22/09/2020
Location: United Kingdom
Posts: 35
Posted: 02:26pm 16 Feb 2021
Copy link to clipboard 
Print this post

  RetroJoe said  @johngill, please have a look here

It should be obvious from the schematic  why they are called pull "up" resistors :)

P.S. is your forum name a Star Trek reference ?


Many thanks for the circuit diagram - very helpful.

P.S. I'm John Gill in real life - I do apologise most profusely for breaking the Prime Directive on Ekos!!    
 
Print this page


To reply to this topic, you need to log in.

© JAQ Software 2024