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!KBDATA is ignored and yes, the signal levels are basic TTL. Where is
your schematic located?<br><br>
Don't forget that the 9100 needs to register the keyboards response to
!KBRESET when you are coding this up. Data rate is 1200 Baud.<br><br>
John :-#)#<br><br>
At 10:59 AM 02/06/2003 -0700, David Shoemaker wrote:<br><br>
<blockquote type=cite class=cite cite><font face="arial" size=2>Kev
pointed me at the right page on the schematics (page 163 in the
9100_svc_part2.pdf). Looking at the schems I think this project
just got easier.</font><br>
<br>
<font face="arial" size=2>I was expecting to have to use a MAX232 (or
similar) TTL (0 - 5v) to RS232 driver chip (+/- 3v). But looking at
the 9100 schematic the keyboard signal is just fed to a 74HCT14 / 74LS04
pair which raise the levels back to TTL. So I think I can just
drive this at TTL levels directly from the microcontroller. Currently
looking at one of the small Atmel parts.</font><br>
<br>
<font face="arial" size=2>So this becomes a single chip solution. I
like it.</font><br>
<br>
<font face="arial" size=2>Anyone want to take a look at the schematic and
vet my answer? Also it looks like though !KBDATA is at pin 1 it
just gets fed to ground so I only need to feed KBDATA.</font><br>
<br>
<font face="arial" size=2>Now all I need to do is figure out what BAUD
rate the 9100 is expecting its data at.</font><br>
<br>
<font face="arial" size=2>David</font></blockquote></body>
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Received on Mon Jun 02 13:51:59 2003
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