1. RAM EXPANSION UP TO 512 K.
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The problem itself isn't that big of a deal.
technical difficulty, the main thing here is
find a good expansion port address. K
unfortunately, the standards proposed
"ATM-turbo", "PROFI" and "Scorpio" provided
were unsuccessful for various reasons: this
and difficult to explain from a logical point
vision, interference with normal operation is significant
number of existing programs
and, most importantly, the cumbersomeness of the hardware
implementation in the form of external modification.
In the end, the developers found
An elegant solution to the problem is to use
two most significant bits of the RAM expansion port up to
128K (#7FFD). This standard, in particular,
supported by some versions of IS-DOS,
programs "CONVER COMMANDER V3.2" and
"Jemmini COMMANDER". To ensure consistent
compatibility of all existing standards
it is recommended to use pre-
testing and configuration
expansion port gradation.
Refinement chips can be soldered onto
available on the computer according to the attached diagram-
meh.
All microcircuits are 1533 or 555 series.
KP12 can be replaced with KP2. Both lines
565 PYS must be replaced with 565 RU7. B
"Pentagon 128" signal A9' is sent together
then A9 to the DD18 multiplexer. Forprovide
development of proper regeneration at targeted
multiplexers (KP11) swap places: B15
and C35, A10 and C34. Instead of B14 we serve "earth"
liu". S_TM9 can be taken from pin 13
DDbCh, and AV_KP11 from the 6th pin DDbZ.
Designations are given according to the Pentagon scheme
128", because exactly this version of "Spectrum"
has become the most popular
noy and requires minimal effort when installing
new 512K RAM.
For owners of "Leningrad" or "Le-
ningrad 2", already modified to 128K, no
The corresponding changes are also given.
LENINGRAD 2. A9' is served instead of A10 on
DD16. Instead of B14, we give a signal that generates
bathtub on the existing free element LI1
from V2 and inverted H2. Instead of A9
We give the A10 from the processor for improvement. Vmes-
then we feed C14 -RAS with 5 DD2, instead of C23 by-
give -H1 with 12 DD1. Signals AB_KP11 and C_TM9
we take up to 128 K from the modification board. Instead
V2 to 4 DD14 in the computer we supply ground.
LENINGRAD 1. A9' is served instead of A8 for 3
DD15. As B14 we use the signal with
pin 4 DD19, and instead of this signal at 3
DD18 we supply "ground". Instead of A9 for modification
we feed A8 from the processor, instead of C14 -RAS
with 9 DD2, and instead of C23 -H1 with 2 DDZCH. Signa-
ly AB_KP11 and C_TM9 are found on the board of the dora-
boots up to 128 K.
ADJUSTMENT. Practice shows that when
installation RU7 with the letters "B", "I", "K" and
Better yet, no adjustment is required. For microcircuits
with other letters you may have to increase
determine the number of power supply containers
but put a capacitance of 47...240 pF between
"ground" and the -RAS signal. RU7-e heat-
much stronger than PYS, especially
in the Pentagon - this should not scare you,
although measures to maximize their ven-
It won't hurt to take tilation.
New memory pages are located according to
to the same RAM addresses as the old ones, they are transferred
switching is carried out by two senior
bits of system port #7FFD (until modifications)
these bits were not used). Arose-
avoiding conflicts between improvements and existing
our programs have not yet observed,
but as a last resort it can be turned off by
ON/OFF switch.
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