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-rw-r--r--converter/ibm4704_usb/4704.txt19
1 files changed, 16 insertions, 3 deletions
diff --git a/converter/ibm4704_usb/4704.txt b/converter/ibm4704_usb/4704.txt
index db584970df..c17d172af1 100644
--- a/converter/ibm4704_usb/4704.txt
+++ b/converter/ibm4704_usb/4704.txt
@@ -16,7 +16,6 @@ http://ed-thelen.org/comp-hist/IBM-ProdAnn/4700.pdf
-
4704 Keyboard Protocol
======================
On powering up the keyboard sends keyboard id; A3h for 6019284(62-key), for example.
@@ -24,6 +23,22 @@ After that firmware enters FC command mode and waits for parameter data from hos
so that it doesn't send any scancode until you send 'FF'(End of FC command).
+Connector
+---------
+ Keyboard Plug from front
+
+ DSUB-9
+ -------------
+ \ N 2 3 4 5 /
+ \ N N N N /
+ ---------
+ 2 GND
+ 3 VCC 5V
+ 4 DATA
+ 5 CLOCK
+ N No connection/No pin.
+
+
Keyboard to Host
----------------
Data bits are LSB first and Pairty is odd. Clock has around 60us high and 30us low part.
@@ -40,7 +55,6 @@ Timing: Host reads bit while Clock is hi.
Stop bit: Keyboard pulls down Data line to lo after 9th clock.
-
Host to Keyboard
----------------
Data bits are LSB first and Pairty is odd. Clock has around 60us high and 30us low part.
@@ -60,7 +74,6 @@ Timing: After Request keyboard pull up Data and down Clock line to low for s
Stop bit: Host releases or pulls up Data line to hi after 9th clock and waits for keybaord pull down the line to lo.
-
Scancodes
---------
Keyboard doesn't send Break code for all keys except for Alt by default.