So how does a PS/2 keyboard interface work?

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[osirisgolad]

"I've got about eight of them here; at least as far as you know..." Should we send someone to check on you?

[marred]

"I've got about 8 of 'em here, at least as far as you know" LOL

[flybackrs]

The reason the Pause/Break key has such a weird scan code is because old 84-key keyboards didn't have that key and used Ctrl+Num Lock for Pause/Break. If you look at the scancode it's actually a make sequence for control and num lock, followed by a break sequence for both—so it acts like you quickly presesed and released control+num lock even if you hold it down.

[samp-w]

Everybody gangsta' until he slides in 8 identical copies of the shift register. (At least as far as we know)

[HenrikDanielsson]

Morgan Freeman narrating the epilogue of this series: "...and as far we know, Ben is still out there, happily building scancode decoders 'til this day...".

[Roxor]

Something to clarify: The two pins Ben said were unused only applies to keyboards. Mice use them and leave the ones used by a keyboard unused. If you've got a PS/2 keyboard with a trackball in it that still only uses one plug, the trackball will be using those pins while the main keyboard uses the other two.

[MIKAEL]

"8 of them as far you know" LMAO. This and the zooming out on the data the HOME key was sending was so funny to me. It's like watching the old commercials "But wait there's more!"

[YoursTruelyMe]

To anyone reading...
Ben's website under credentials says "I went to school for computer science, but failed out after the first year and have no degree"
Why I bring this to attention is because with such a deep understanding, I assumed this guy had several PhDs. The fact that one of these videos is more informative than some of the most rigorous 4 year programs is a true testament to self education. This is the golden corner of YouTube, please never stop.

[RuiMartins]

Scan codes are based on a matrix of vertical and horizontal lines, at least for the main section of the keyboard.
That is why key "1" and "2" start with Hex1 (same matrix vertical), and similar for "3", "4", "5" starting with Hex2 and "6", "7", "8" starting with Hex3, ... they belong to the same keyboard matrix vertical scan line. The right Hex digit is the horizontal matrix scan line.

The other special keys, like: "F"unction, Insert, Home, PageUp, Delete, End, PageUp, System/PrintScreen, Scroll Lock, Break/Pause, ... depend on how they were mapped on the Matrix of the first keyboard that added them.
For example, F1 to F6, where originally listed vertically on the left side of the keyboard, hence all their codes start with Hex0.

The IBM standard evolved with each successive keyboard, with new keys, that were usually mapped to the closest vertical and horizontal lines of the scan matrix. Basically to make it as simple as possible to route the matrix circuit onto the keyboard PCB, since any pattern can be easily handled by the software layer.

[itsthesola]

"5v is black"
Okay, now what? Next you're gonna tell me data is red?

"data is red"


oh no.

[NXaiUL]

Your channel is worth more than gold. This stuff you are making is timeless.

[bertholtappels]

This guy turns a KEYBOARD PROTOCOL into binge-worthy content. That’s one of those things about 2021 that I didn’t see coming.

[HorochovPL]

Two shift registers on a single board?
Don't worry, I have another similar board.
Wait, there's three actually!
So, how many boards does Ben have? All of them.

[Ntech]

My breadboards look like rotten spaghetti, while yours look like works of art.

[Vaibhavhayaran]

It's 2030 and Ben is building a Quantum computer on breadboard.

[dsgeyer]

“Black is 5v, figures” lololol love these videos. I need to quit everything and just do these videos all day

[MovieMationStudios]

Ben busted out that ready-made second shift register breadboard like a Food Network chef

[devnol]

What if you didn't invert the latch clock and just fed it a falling edge clock, so that when it rises it would trigger the latch?

[tyisafk]

Me, a nail biter, seeing someone strip wires by hand:

Pure sorcery.

[StefanoBorini]

I did some research on the scancode origin when self-building a keyboard. I was not able to find anything authoritative, so the best guess I have for its strange pattern is the ye olde connection matrix they chose originally for the buttons. In other words, in the old days they connected the buttons with a reasonable (cheap to produce) row/col network, then the internal chip scans the rows and gets which column is connected to identify which key is pressed. So what you might get in the original, basic set, is simply the encoded row/column position of the button _according_ to the wiring matrix (not the visual layout). But I might be wrong.