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@@ -16,7 +16,6 @@ http://ed-thelen.org/comp-hist/IBM-ProdAnn/4700.pdf
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-
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4704 Keyboard Protocol
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======================
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On powering up the keyboard sends keyboard id; A3h for 6019284(62-key), for example.
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@@ -24,6 +23,22 @@ After that firmware enters FC command mode and waits for parameter data from hos
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so that it doesn't send any scancode until you send 'FF'(End of FC command).
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+Connector
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+---------
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+ Keyboard Plug from front
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+
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+ DSUB-9
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+ -------------
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+ \ N 2 3 4 5 /
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+ \ N N N N /
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+ ---------
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+ 2 GND
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+ 3 VCC 5V
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+ 4 DATA
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+ 5 CLOCK
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+ N No connection/No pin.
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+
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+
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Keyboard to Host
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----------------
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Data bits are LSB first and Pairty is odd. Clock has around 60us high and 30us low part.
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@@ -40,7 +55,6 @@ Timing: Host reads bit while Clock is hi.
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Stop bit: Keyboard pulls down Data line to lo after 9th clock.
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-
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Host to Keyboard
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----------------
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Data bits are LSB first and Pairty is odd. Clock has around 60us high and 30us low part.
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@@ -60,7 +74,6 @@ Timing: After Request keyboard pull up Data and down Clock line to low for s
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Stop bit: Host releases or pulls up Data line to hi after 9th clock and waits for keybaord pull down the line to lo.
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-
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Scancodes
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---------
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Keyboard doesn't send Break code for all keys except for Alt by default.
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tmk