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Solve : PS/2 keyboard interface?

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Hi!

I would just like to know what the PS/2-keyboard interface look like. Is it RS232 or?

Best regards, Roger
PS
Today I managed to manually and serially clock data to a LCD-display by USING a cross-coupled pair of NAND-gates (i.e a contact-bounce eliminator) and a manual clock-switch. I yelled happiness when I got this to work. Most importantly, my technical manager laughed when he asked how I have used a computer and I said "what computer"!http://en.wikipedia.org/wiki/PS/2_connectorHi quaxo!

Thanks for the link.

I have now read it but did not get that much wiser.

The things I did however learn were:

1) Serial data at 10 to 16 kHz with 1 stop bit, 1 start bit, 1 parity bit (odd)
2) Actual pin configuration.

4 pins seems to be used in the (FEMALE, counted in a very special way) pin connector. These are:

1) Pin 1, DATA
2) Pin 3, GND
3) Pin 4, VCC
4) Pin 5, CLK

The rest of the pins (2) are not used.

This seems easy enough.

The question is how data is configured.

Is it plain "TTL" (0-5V), a start-bit, a stop-bit and a parity-bit only?

Or is it some RS232 with +/-5V?

I am sorry, but that Wikipedia article did not reveal this.

This means that the question remains.

Best rergards, Roger
PS
It seems like the start-bit is a zero (>3V) and the stop-bit is a one (<-3V).

This implies that the parity-bit should be <-3V (=1) for odd.

But this is only if the protocol actually is RS232.


Quote from: rogerk8 on November 27, 2012, 03:38:12 PM

The question is how data is configured.

Is it plain "TTL" (0-5V), a start-bit, a stop-bit and a parity-bit only?

Or is it some RS232 with +/-5V?

I am sorry, but that Wikipedia article did not reveal this.

This means that the question remains.

Your original question was:
Quote from: rogerk8 on November 23, 2012, 06:08:43 PM
I would just like to know what the PS/2-keyboard interface look like. Is it RS232 or?

To which I've linked an article that shows a picture answering your question. You didn't ask anything about data in your initial question.

PS/2 is not an RS-232 type. It replaced the RS-232 DB-9 type plugs for the purpose of a mouse, and the AT DIN-5 for the purpose of a keyboard. All of this is outlined in that article and other articles linked to it. Take the TIME to read everything. Use Google, research a bit.

Do you have a specific question, problem, or issue you're trying to resolve? Please be more specific about what you need.Hi quaxo!

Thank you for your reply.

I will do as you suggest that is to do some research of my own.

I have however done some but haven't got that much wiser.

But I will do some more.

You should know that this is not an immediate emergency.

This is just a wish.

I am designing a CPU using a CPLD.

It seems like I might actually be able to make it work. But I am still unsure. Yet, there is some hope.

And if I ever get it to work I might want to expand the input interface to incorporate an actual PS/2 keyboard.

Right now I am just using two simple BCD-switches.

But it would be nice if I could use a keyboard instead in that amazing possibility that my CPU will actually work.

I have chosen PS/2 DUE to simplicity.

Or so I thought...

Finally, I thought that the whole point of a forum is to cut corners REGARDING research emforts...

Best regards, Roger


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