──── Technodrome ───
EXPANSION OF RAM UP TO 512K IN COMPUTERS
WITH COMMON MEMORY FIELD
Development of software and hardware
support "ZX Spectrum" is increasingly being blocked
the computer has insufficient RAM.
The problem of expanding RAM is technically not
is particularly difficult, the main thing is
for a long time there was no single standard
dart for expansion. Standards proposed
ATM turbo and PROFI, remained practically
ki unclaimed due to unpopularity
of these computers in the regions and is ridiculous
small software on them.
Moreover, their addressing methods are logically
difficult to explain, cumbersome for hardware
implementation and lead to incompatibility with
significant number of existing
programs.
As a result of many years of searching,
user trial and error "ZX Spectrum"
Recently, a single standard has emerged
to expand RAM, which is proposed
to you in this issue. This standard, in
in particular, it is supported by the IS-DOS system,
programs "CONVER COMMANDER V3.2R"and
"Jemmini Commander 48/512". Finally
affirmation of thisstandard for
collapsed growth expected in the CIS space
number of programs modified or created
especially for 512 K, in particular copying
boxes, monoblocks for block games, multi-
typification, digitization of image and sound
etc.
We offer modification microcircuits to attack
yat on existing in the computer according to the scheme:
1 k
┌─═══── +5V
ONЄ OFF │
┌──Ї ────────╪
─── ─┴─ KD 522 │ 1 ┌─────┐
RES ────────────┤<────╪───╪R T │5
┌──────┘ 2 │ Q├
D6 ───────────┼──────────┤D │
│ 3 │ │
C-TM9 ────────╤┼──────────┤C ─│6
││ 4 │ Q╪──┐
D1 - 555 TM2 ││ +5V ─────╪S │ │
D2 - 555 KP12 ││ D1.1 └─────┘ │
D3 - 555 ЛЕ 1 ││ │
││ │
A/B-КП11 ──┼┼─┐ │
││ │ │
┌─────────────┘│ │ │
│┌─────────────┘ │ │
││┌──────────────┼─────────────────┘
│││┌─────────────╢
││││ 2┌────┐ │
│││└──┤ 1 │1 │
│││ 3│ ╪─────┼──── A9'
││└───┤D3.4│ │
││ └────┘ │ 5┌────┐
│└──┐ 13┌─────┐ └──┤ 1 │4
│ └───╪R T │9 6│ ╪─┐
│ 12│ Q├ ┌──┤D3.3│ │
│ D7 ──┤D │ │ └────┘ │
│ 11│ │ │ │
└───────┤C ─│8 │ │
10│ Q╪──┘ │
┌──╪S │ │
│ └─────┘ D1.2 │
└── +5V │
┌───┘
┌─────────────────┘ ┌── на 1-е
│ 10┌──┬───┬──┐ │ выводы
│ ┌────┤B0│MUX│ │ │ mmm
│─┴─ 11│ │ │ │ │ 565RU7
B14 ─┼──────┤B1│ │ │9 │
│ 12│ │ │YB├──┘
└──────┤B2│ │ │
13│ │ │ │
A9 ────────┤B3│ │ │
15├──┤ │ │
┌────╪SB│ │ │
─┴─ 14├──┤ │ │
C14 ────────┤0 │ │ │
2│ │ │ │
C23 ────────┤1 │D2 │ │
└──┴───┴──┘
In "Pentagon 128" it is advisable to combine
then D3.3 and D3.4 apply those available on the plan-
those free elements LI1: DD97.3 and
DD97.4, sending Q signals to them from D1 instead
-Q (from pins 5 and 9, respectively, instead of
6 and 8).
Then instead of A/B-KP11 we use sig-
cash with 6 DD63, inverted to DD86.5.
As a result, only 2 additional
additional bonuses: TM2 and KP12.
KP12 can be replaced with KP2. All mic-
circuit diagrams - series 1533 or 555. Both lines
565 RU5 will have to be replaced with 565 RU7.
In "Pentagon 128" we advise you to solder
KP12 is on top of DD17, and TM2 is on DD66. Signal
A9' is supplied instead of A9 to the multiplexer
DD18. On address multiplexers (KP11)
swap places: B15 and C35, A10 and C34,
instead of B14 we serve"ground". Signal C-TM9
can be taken from the 13th pin of DD64, and
A/V-KP11 from the 6th pin of DD63.
All designations are given according to the "Penta-
range 128", because it is this version of "Spect-
rum'a" in person became the most
popular and requires the least effort when
installing 512K RAM on the board. For those who have
ley other popular versions of the computer,
already modified to 128K, below are
corresponding changes.
LENINGRAD 2. A9' is served instead of A10 on
DD16. Instead of B14, we give a signal that generates
bathroom according to the picture:
1┌──────┐
V2 ──┤ & │3
── 2│ ├───
H2 ──┤DD44.1│
└──────┘
In this case, -H2 is obtained from H2 inverted
by moving on the free element m-we LE1 to-
work, and the free element DD44.1 is found
located on the computer board. Instead of A9, submit
I'm going to upgrade the A10 from the processor. Instead of
C14 is supplied -RAS with 5 DD2, instead of C23 we are supplied
-H1 with 12 DD1. Signals A/B-KP11 and C-TM9 without
Repair from the board upgrade to 128 K. Instead of V2
We supply ground to 4 DD14 in the computer.
LENINGRAD 1. A9' is served instead of A8 on
3 DD15. As B14 we use the signal with
output4 DD19, and instead of this signal at 3
DD18 we supply "ground". Introduced A9 for modifications
we feed A8 from the processor, instead of C14 -RAS
with 9 DD2, and instead of C23 -H1 with 2 DD34. Signa-
ly A/B-KP11 and C-TM9 are found on the dora board
boots up to 128 K.
ADJUSTMENT AND OPERATION. Check: it works
whether 565 RU7 is in your computer. At the Pentago
not 128" is required for this
We can make the indicated changes on the KP11s.
We put RU7 on any RU5 with all the terminals,
except 1 and 14. We apply ground to the 1st pin,
and connect the 14th to the bus instead of the 14th pin
water corresponding to RU5. Both lines of RAM
128K should work as before. In pro-
Otherwise, select the capacity for -RAS
(0...120 pF). For RU7 with the letters "B", "I",
"K" and better, adjustment is usually not needed, maybe
it may be necessary to increase the number of capacitors
tey on nutrition. Now we assemble and connect
tea finalization.
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 the system port #7FFD (until modification
these bits were not used). When
no revision conflicts
with old programs, it is completely blocked
switched by ON/OFF switch.
Max Iwamoto
P.S. Reprintthis article is allowed
without agreement with the author.
Scorpion owners can rejoice,
because there is a simple possibility
computer improvements (memory expansion)
up to one MByte. I hope that the author
will reveal to us his KNOW HOW and wish us
I would like to thank all our readers for this.
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