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geekhack Projects => Making Stuff Together! => Topic started by: telnet on Sun, 24 May 2015, 22:17:50

Title: Help verify my TKL wire-matrix layout.
Post by: telnet on Sun, 24 May 2015, 22:17:50
I'm building my first hand wired board. 
The rows have been soldered, but I need some advice on my planned columns.

Can someone please verify if these columns are connected in the most effective manner.  I'm going to use a Teensy 2.0 as the controller.

(http://i.imgur.com/bPInPoP.jpg)

Thanks
Title: Re: Help verify my TKL wire-matrix layout.
Post by: dorkvader on Mon, 25 May 2015, 03:46:47
You have 17 colums showing and 5 rows. This requires 22 IO pins.

Teensy 2.0 has 25 IO pins.

You could wire them up in a more effective or compact manner, using less IO pins, but this should work.

Remember to not wire anything up to the power gnd and rst pins on the end of the teensy, and I recommend avoiding PD6 as it's the LED pin it sometimes has a problem.
(http://www.pjrc.com/teensy/pinout2a.png)

Personally I'd wire it up a little differently but that's purely an aesthetic choice.
Title: Re: Help verify my TKL wire-matrix layout.
Post by: berserkfan on Mon, 25 May 2015, 10:38:01
If you use up all your pins that won't leave enough for LEDs. How about merging the tenkey area into one big column? But I admit that I don't know how to do that in practice.
Title: Re: Help verify my TKL wire-matrix layout.
Post by: suicidal_orange on Mon, 25 May 2015, 10:54:08
If you use up all your pins that won't leave enough for LEDs. How about merging the tenkey area into one big column? But I admit that I don't know how to do that in practice.

You would need to connect all the diodes together to make them a row, then connect each switch to one of the existing columns in a meaningful way.  It only saves two pins and would look messy, so isn't worth the confusion - 3 pins is enough for LEDs.


@telnet the only inefficiency I see in terms of wire length is that Escape could be connected to the end column, saving you maybe 1cm :))
Title: Re: Help verify my TKL wire-matrix layout.
Post by: telnet on Mon, 25 May 2015, 12:30:35
You have 17 colums showing and 5 rows. This requires 22 IO pins.

Teensy 2.0 has 25 IO pins.

You could wire them up in a more effective or compact manner, using less IO pins, but this should work.

Remember to not wire anything up to the power gnd and rst pins on the end of the teensy, and I recommend avoiding PD6 as it's the LED pin it sometimes has a problem.
Show Image
(http://www.pjrc.com/teensy/pinout2a.png)


Personally I'd wire it up a little differently but that's purely an aesthetic choice.

Thanks for the tip on avoiding PD6.   Do you have any prior builds or samples on how you would wire it up?



If you use up all your pins that won't leave enough for LEDs. How about merging the tenkey area into one big column? But I admit that I don't know how to do that in practice.

I wasn't planning on any backlight leds in this build, maybe just two indicator lights, but I have enough pins for those two.



If you use up all your pins that won't leave enough for LEDs. How about merging the tenkey area into one big column? But I admit that I don't know how to do that in practice.

You would need to connect all the diodes together to make them a row, then connect each switch to one of the existing columns in a meaningful way.  It only saves two pins and would look messy, so isn't worth the confusion - 3 pins is enough for LEDs.


@telnet the only inefficiency I see in terms of wire length is that Escape could be connected to the end column, saving you maybe 1cm :))

I might switch that escape key column depending on where the teensy goes.
Out of curiosity regarding leds, if I were to add them on, what else would I need other than resistors and the leds?
Title: Re: Help verify my TKL wire-matrix layout.
Post by: suicidal_orange on Mon, 25 May 2015, 14:34:39
Do you have any prior builds or samples on how you would wire it up?

All the pins marked P[letter][number] are the IO pins, avoid PD6 but other than that you can connect anything to any of them.  It looks better if the wires don't overlap but there is no problem with interference, so don't worry if a couple do.

Quote
I might switch that escape key column depending on where the teensy goes.
Out of curiosity regarding leds, if I were to add them on, what else would I need other than resistors and the leds?

For just a couple of LEDs all you need are resistors and a bit of wire to connect them.

Just make sure you know what you connected where as you'll need to know to configure the firmare :)