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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>The part you found was probably a variant
of the 6116, 2K x 8 “byte wide”. These have compatible pinouts
with EPROMs (in this case, a 2716). I know that there is also a 6164, which is
8K x8; 8 of these will give you a full 64k (but you would have to emulate the
H8’s “extended configuration card” to allow both “normal”
(e.g. HDOS and monitor ROM) operation, and an all-RAM configuration for CP/M.
There might be a 64K x 8 memory card (one chip for the entire 64K), but
precisely because of the need to support both normal and extended modes, it
might be easier to implement the necessary card with smaller parts. However,
6116’s are plentiful and cheap, I’d think you could find them for
more like $2 each from a surplus dealer (as used pulls, but as long as they
work, who cares).<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
sebhc-bounces@sebhc.org [mailto:sebhc-bounces@sebhc.org] <b><span
style='font-weight:bold'>On Behalf Of </span></b>davidwallace2000@comcast.net<br>
<b><span style='font-weight:bold'>Sent:</span></b> Sunday, August 13, 2006 8:39
PM<br>
<b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">sebhc@sebhc.org</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [sebhc] memory for
the h-8</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>The bad news is you probably won't find 4044s, or you'll pay
collectors' prices for them.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>The good news is that almost any modern static RAM could be adapted to
the H8 bus if you don't insist of trying to make it fit in the WH8-16
card. It's a matter of making the address decoding work and buffering the
address, data and control lines to the RAM -- and the schematic of the WH8-16
will show you how to do that.<o:p></o:p></span></font></p>
</div>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Most anything you could buy would be faster than needed (which is not
harmful) and you'd probably wind up with one card that fully populates the H8's
address space.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Example: I found a 2K x 8 SRAM part with 250 ns access time at DigiKey
for $4.28 (each). It's a 24-pin DIP (5V VCC) and appears at a
cursory glance to be compatible with the requirements. An octal decoder
and some buffers and eight of these chips would make a 16K memory board in
probably half a card's worth of space. The chip cost would be under $50.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>See<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><a
href="http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=81422&Row=148798&Site=US">http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=81422&Row=148798&Site=US</a><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
<blockquote style='border:none;border-left:solid #1010FF 1.5pt;padding:0in 0in 0in 4.0pt;
margin-left:3.75pt;margin-top:5.0pt;margin-bottom:5.0pt'>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>-------------- Original message -------------- <br>
From: WVerish@aol.com <br>
<br>
</span></font><font size=2 color=black face=Arial id="role_document"><span
style='font-size:10.0pt;font-family:Arial;color:black'><o:p></o:p></span></font></p>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>Dear Carroll:<o:p></o:p></span></font></p>
</div>
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<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>
I have a 16 k static RAM memory board that came with my H-8, but it is <strong><b><font
face=Arial><span style='font-family:Arial'>un-populated</span></font></b></strong>.
The chips required for it are TMS4044 chipsThey are 4096 by 1 bit. The computer
currently has only 8K of static RAM installed. This makes it very hard to write
any <u>real</u> BASIC programs due to the lack of string handling capability
with only B.H. BASIC instead of extended B.H. BASIC. I know that my 16K board
could probably work with other chips, but due to their cost I really can't
afford to make a mistake. Any ideas? <o:p></o:p></span></font></p>
</div>
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<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'>Thanks,<o:p></o:p></span></font></p>
</div>
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<p class=MsoNormal><font size=2 color=black face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:black'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><st1:City w:st="on"><st1:place w:st="on"><font size=2
color=black face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:black'>Wayne</span></font></st1:place></st1:City><font size=2
color=black face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:black'><o:p></o:p></span></font></p>
</div>
</blockquote>
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