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PS/2 keyboard
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This is a collection of PS/2 keyboard communication examples.
A random PS/2 keyboard and a random PC mainboard were used as data source.
For details see:
https://web.archive.org/web/20161231114842/http://www.computer-engineering.org/ps2protocol/
https://www.avrfreaks.net/sites/default/files/PS2%20Keyboard.pdf
Logic analyzer setup
--------------------
The logic analyzer used was a Saleae Logic (at 24 MHz):
Probe PS/2
----------------
2 Data
3 Clock
ps2_keyboard_asdfgh.sr
----------------------
This file contains a sequence of keypresses on a standard PS/2 keyboard:
a, s, d, f, g. The dump contains the "make code" and "break code" of each key.
After each transmission, the receiving controller appears to pull the clock
line low for more than 100 microseconds. This inhibits transmission until the
clock line is released, presumably because the receiving controller needs time
to process data. Due to this, additional very short clock pulses can be
observed, as the controller starts inhibiting communication only shortly after
packets are received.
ps2_keyboard_asdfgh_no_inhibit.sr
---------------------------------
The keys a, s, d, f and g pressed on a random PS/2 keyboard.
In this dump, the receiving end was passive, without inhibiting communication.
Thus only clock pulses produced by the keyboard can be observed.
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