[Coladam] Memory expanders

Rich Drushel drushel at apk.net
Sat Dec 11 11:40:31 CET 2010

On Fri, December 10, 2010 11:59 pm, Ellen and Craig Lindholm wrote:

> Does anyone have information as to how the addressing is done with these
> old cards? Even some sample assembly code that accesses the memory
> expanders would help as I can determine what the hardware is doing from
> the instructions.

     Let me get out of the upcoming finals week (both my exams are
Tuesday, I am still writing one of them, and then I have about 150
papers and reports to grade by Friday).  I can then give you sample
code or more detailed E-mail explanations.

     However, note the the ADAM Technical Manual (ATM) has info
about accessing the 64K expander, and larger expanders work the same
way, except that a bank select value is sent out an additional port
(66 decimal from memory).  The SmartBASIC 1.x source for the extended
IN and OUT commands will tell you how to address any ADAM memory space,
though likely the code is not commented (it was in the handwritten
source, but remember that SB1.x was created as a series of POKES to
the SB memory map followed by a BSAVE; the electronic .ASM "source"
was reverse-engineered from this binary.

http://drushel.cwru.edu/atm/atm.html       ;ADAM Technical Manual

http://junior.apk.net/~drushel/coleco/files/sb1x/sb1x20y.zip   ;SB1.x source

http://drushel.cwru.edu/sb1x/SB1x_manual_3p_regen.pdf  ;SB1.x user manual

     Sorry to be so terse, this is the worst time of the academic year
for me :-(


Richard F. Drushel, Ph.D.            | "They fell:  for Heaven to them no hope
Department of Biology                |  imparts / Who hear not for the beating
Case Western Reserve University      |  of their hearts."
Cleveland, Ohio  44106-7080  U.S.A.  |         -- Edgar Allan Poe, "Al-Aaraaf"

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