Monday, 13 June 2016

Electronics Tinkering : Project Plan #1

I've been wanting to tinker with some electronics for ages, and in my store, I have some Z80 CPU's and lots of TTL logic.  But before I dive into that, and since I'm totally untrained, I thought I'd have a play about with my soldering iron and see what I could mash together.

My plan therefore is to desolder a PS2 connector from one of the Socket 775 motherboards I killed, and to connect it to an arduino uno to read the pins.

Looking at this, I can mount the PS2 connector to a project board, solder on a set of headers and wire each pin to a known point on the header.

From there I can use jumper cables from my breadboard to bridge from the headers on the project board to the arduino.

At least, this is the theory.

The first thing I need to worry about is the clock, I have no idea what the clock rate is, if I need a crystal, or if a capacitor charging & discharging will do, or even if I can create the signal from a GPIO pin or PWM pin from the arduino... I'll have to look into that and let you all know.

My rough schematic is going to look like this on the project board:

The outer shell will be going to ground, and it has four feed to solder.  Then the four pins seem to point to clock, Ground, VCC and Data.  I'm not clear on which of the pins below become the sockets, so I'll have to insert something into the socket holes and check for continuity to the pins to know the order.

But each group of four will be soldered to a header, which I've marked read and blue.  One will be the upper set of ports, the other the lower.  I'm not going to distinguish keyboard/mouse because I just want a keyboard signal.

So, a bit of soldering with my new iron.  I'm going to have to de-solder with it too.

Below follows a list of the links I'm interested in looking through:

From the Wikipedia entry (yes I read Wikipedia) states:

"Communication is serialsynchronous and bidirectional.[1] The attached device generates the clock signal. The host controls communication using the clock line; when the host pulls the clock low, communication from the device is inhibited."

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