please dont rip this site

PC Hardware Input/Output Port: Keyboard

The keyboard scan codes you see listed in Books and FAQs and so forth are NOT current for a MFII (101-key expanded) keyboard. The Linux source code does document all this.

Typical data transfer speed from the keyboard  is approx. 8kHz . The clock pulses are 60 or 70 uS long so 120uS for the period. The clock rate can differ significantly between  PCs

Many keyboards have automatic XT/AT mode detection. This worked in several different ways. e.g. one keyboard would send a code with a deliberate parity error, and if the host didn't request a re-send it went into XT mode.

Topics:

Michael Hetherington's USB Keyboard demo

Caller ID Keyboard wedge: ddj article and source code

See also:

letter decender? curve? circle? heavy? leftheavy? two parts? topheavy? points?
a A X ? X B 1-2
b B X L ? X 1-2
c C X L X 2
d D X R L? 1-2
e E X X L X X 1-2
f F X L X ? X 3-4
g G X X X RT LB X 1-2
h H X L ? X 3-6
i I X 2-4
j J X X R X 2-3
k K L X 4
l L ? L 2
m M X TL T X X 2-4
n N X TL ? X X 2-3
o O X 0
p P X X LT X 1-2
q Q X X RT RB X 1-2
r R X LT X X 3
s S X 2
t T T X 4
u U X B 2-3
v V T X 2
w W X B 2-4
x X 4
y Y X ? T X 3-4
z Z 2

See also:

Archive:

Uche Nwoko of Multi-Electronics Design Says:

A simple experiment for those looking for, a common keyboard that is capable of encoding 9 key strokes into four binary bit. what I did was to use an IC 74HC147, known as 10 to 4 line priority encoder, as a keyboard to controle a wireless remote system, with this IC I can be able to achive an Output of 4 binary code from 0 to 9, whereby i interface the binary output with any encoder to give me the right data i needed to controle my design.
To construct a keboard from 74Hc147 all 1 to 9 input pins should pull high with 10k resistors, then each of the input is connected to micro push buttons,with this buttons i can be able to sellect any of the input from 1 to 9, if all of the 9 iputs are on high position, the output will be Automatically 0 (Zero), i.e if the output is invert, that is why I did not have 0 button on my keboard, with the help of cd4511 you can be able to read out the output from 7 segment display.
Below is the input and Output Table.

A B C D 1 2 3 4 5 6 7 8 9
1 1 1 1 = 1 1 1 1 1 1 1 1 1 when output invert = 0, if not invert = F
0 1 1 0 = 1 1 1 1 1 1 1 1 0 when output invert = 9, if not invert = 6
1 1 1 0 = 1 1 1 1 1 1 1 0 1 when output invert = 8, if not invert = 7
0 0 0 1 = 1 1 1 1 1 1 0 1 1 when output invert = 7, if not invert = 8
1 0 0 1 = 1 1 1 1 1 0 1 1 1 when output invert = 6, if not invert = 9
0 1 0 1 = 1 1 1 1 0 1 1 1 1 when output invert = 5, if not invert = A
1 1 0 1 = 1 1 1 0 1 1 1 1 1 when output invert = 4, if not invert = B
0 0 1 1 = 1 1 0 1 1 1 1 1 1 when output invert = 3, if not invert = C
1 0 1 1 = 1 0 1 1 1 1 1 1 1 when output invert = 2, if not invert = D
0 1 1 1 = 0 1 1 1 1 1 1 1 1 when output invert = 1, if not invert = E

The above table is exctly how the input and out out look like, if necessary the output can be invert with the help of Ic CD4069 or CD4049, I wish any reader a success, if you want to try this simple design.
+ +

Questions:

file: /Techref/io/keyboard.htm, 16KB, , updated: 2022/5/24 16:59, local time: 2024/12/26 23:05,
TOP NEW HELP FIND: 
18.222.161.245:LOG IN
 ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
Please DO link to this page! Digg it! / MAKE!

<A HREF="http://ecomorder.com/Techref/io/keyboard.htm"> PC Keyboards, AT Keyboard, PS2 Keyboard</A>
After you find an appropriate page, you are invited to your to this massmind site! (posts will be visible only to you before review) Just type a nice message (short messages are blocked as spam) in the box and press the Post button. (HTML welcomed, but not the <A tag: Instead, use the link box to link to another page. A tutorial is available Members can login to post directly, become page editors, and be credited for their posts.


Link? Put it here: 
if you want a response, please enter your email address: 
Attn spammers: All posts are reviewed before being made visible to anyone other than the poster.
Did you find what you needed?
 

Welcome to ecomorder.com!

 
Here is a great gift for computer geeks or widows:
The Backwoods Guide to Computer Lingo

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  .