Shadow RAM controller
(c) Zhovtonoga Igor. 2001
________________________________________
1. Basic functions.
This controller can work: a) as
cache memory; b) replace system pages -
new ROM with downloadable firmware. In bu-
in the future it will be possible to perform the functions
non-volatile RAM disk.
Used as RAM
There is a CMOS (CMOS) chip with a volume of 32 or
128 kilobytes (D8).
2. Description of work.
In this design, the cache is locked
programmatic "opening". The block works
alignment through element D2.1 and turns on/
disabled by software.
If afterdownloads to cache RC 1.96 or
Quick 2.6 install lock program
TEST4.30, etc. will show no cache,
the XLC v3.5 program will work, and when
pressing S1 will launch COMMANDER from ke-
sha.
When "opening" the cache, trigger D3.1 is installed
is set to "0" at the /R micros input
circuit D4 comes "1", outputs of the microcircuit
D4 go to Z-state, to address
inputs (A14-A15) of the operational chip
memory (D8) is supplied as units.
* Numbering of digits, addresses, pages
RAM, ROM starts with number "0".
Thus, the cache is always allocated
last page of the chip used
RAM.
S1 - momentary button, diode anode
V1 is connected to the "MAGIK" button.
Such a connection is possible if other
The output of the "MAGIK" button is connected to
body If this is not so, then you can
connect diode V1, replace V2 with
jumper and put a button in place of S1
with commit, then the cache will be accessed
occur by pressing "MAGIK" when
closed position S1.Other implementation options are also possible
hardware cache access.
To work in system replacement mode
ROM bootable RAM needs to be made
loading the corresponding RAM pages
controller and also program
controller ports.
Microcircuit D4 (IP26) performs
programmable decoder functions
pages of system ROM and controller RAM.
This chip contains four
4-bit register (l.1).
Writing to the registers of the D4 microcircuit
is provided as a port with addressm 62455
(FЗF7).
The assignment of the bits of this port is as follows:
blowing:
D2 , D6 , D7 - set RAM page
controller projected to addresses #0000H-
#ЗFFFH . If the RAM capacity is 32 kilobytes -
digits D6, D7 are not taken into account. Corresponding
the effect of these bits and address inputs
D8 RAM chips are:
D2=A14 : D6=A15 : D7=A16 .
D3 and D4 - setting the system page
ROM that needs to be replaced.
In the computers "PROFI" and "PENTAGON"
correspondence of digits D3, D4 and pages
The ROM is as shown in Table 1.
Digits ! Conclusions!
port !system= ! Tab.1
62455! new ROM!
! !
D3! D4! 27! 1!
==========================
0! 0! 0! 0! 0 pages
==========================
1! 0! 1! 0! TR=DOS
==========================
0! 1! 0! 1! BAS128
==========================
1! 1! 1! 1! BAS48
In computers of other models, the location
ROM page firmware may be different.
D5 - gives a command (when set to
" 1 " ) connection page RAM control-
lera specified by digits D5-D7 instead
ROM pages specified by bits D3, D4
port 62455.
When D5 is set to "0" it is possible
write to the RAM page of the controller
tsirovonnuyu inaddresses #0000H-#ЗFFFH . Blo-
The entry in the controller RAM must be assigned
be disabled.
Other settings are made by port with
address 64503 ( FBF7 ) .
The purpose of the bits of this port is as follows:
D1 - "0" software lock
connection to cache memory.
D2 - "0" RAM read blocking
controller
D3 - "1" blocking writing to ports
controller Unlocking - by turning off
food .
D4 - "0" blocking writing to RAM
controller Ability to write to cache
remains .
After turning on the power, all digits
port 64503 is set to "0".
If you plan to use a cache-pa
memory to the last page of the controller RAMничего не загружается
Please note:
1-year-old slightly larger size
2-я часть схемы это сам контроллер
Pantera>By the way, if you don’t have
mikruhi 15ZZIR26 in the CIS equivalent,
then don’t be too upset, because... try it
look for her among the bourgeoisie with that name
type (74)(A)LSb70. As is known, one drill-
Zhuyskaya mikruha is more reliable than our 3. Here
for example, I try not to use
take away our mikruhs, because they no longer have that
whose quality is the same as in the USSR. Bought a bunch
burnt 38bDX boards and all sorts of controllers
took a gas burner and went ahead :-).
3. Programming
Let's assume that we have installed
D8 chip with a capacity of 32kb and we need
download firmware "GlukS.3k" instead of
BAS128 and RC 1.96 in cache.
10 OUT 62455.0 ! In all categories of all
20 OUT 62455.8 ! microcircuit registers
30 OUT 62455.16 ! D4 write "0"
40 OUT 62455.24 !
50 OUT 64503.16 ! Disable blocking
! records in RAM
60 RANDOMIZE USR 15619 : REM : LOAD
"GlukS.3k" CODE 0
70 OUT 62455.48 ! Instead of 2nd page
! ROM (BAS128) is now
! will be connected
! 0th page
! Controller RAM
80 OUT 64503.6 ! Disable blocking:
! a) software
! "opening" cache
! b) reading RAM
! controller
We launch the program and after pressing
"RES" instead of the BAS128 screensaver wewe can
see the menu "GlukS.3k". Turn on re-
press clear cache, launch RC 1.96,
by pressing key "i" . Again press "RES" and exit
Option "Exit CH" launch RC 1.96.
Another sample program to download
firmware "048_ROM" instead of VACH8 and
"dos13f" in place of TR-DOS:
10 OUT 62455.0
20 OUT 62455.8
30 OUT 62455.16
40 OUT 62455.24
50 OUT 64503.16
60 RANDOMIZE USR 15619 : REM : LOAD
"dos13f" CODE 0
70 OUT 62455.12
80 RANDOMIZE USR 15619 : REM : LOAD
"048_ROM" CODE 0
90 OUT 62455.40
100 OUT 62455.32
110 OUT 62455.60
120 OUT 64503.4
Program for operating the controller in real time
RAM disk mode is currently not written
sana
4. Assembly.
Since the printed circuit boards are factory-made
cooking assembled or empty for this
there is no controller and does not “really” anticipate
you will have to assemble it on the board
own production or on a breadboard
printed circuit board. "home" technology
production of boards has been repeatedly described -
appeared in literature. From the "bourgeois"
devices for making printed materials
boards are now on sale:special
"Water-resistatn" marker and varnish-photore-
zist POSITIV 20 .
But the use of a breadboard is still
more convenient due to the possibility of simpler
making additions to the diagram.
5. Setup.
Instead of what is indicated on the circuit diagram
ME 1533 series chips can be used
Episode 555.
The structure was manufactured in the 1st production
specimen and therefore statistical data
about the performance of this scheme with other
details are missing.
Actually, adjustment may not be necessary -
xia . How to signal a ROM lock(Block ROM) depends on the computer circuit.
You might have to experiment with this.
to rove.
Universal protection against failures is
installation on interlocking power circuits
capacitors
literature:
1. "Logic ICs KR1533 KR1554"
I.I. Petrovsky and others.
March 24 - May 10, 2001
P.S. The design is made comparatively
recently and most likely this version is not
final, but decided to publish
this development because it works quite well
capable .
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Pantera> As a metal worker, I want to note that
it'll be a cool thing. I'm this one
I’ll definitely make myself a controller, and once
vodka will be accompanied by Nemo-bus. Well, for those
who does not have a screw in IS-DOS is completely noticeable
specifically. Write a driver and enjoy
IS-DOS on a RAM disk.Also, a little advice:
Instead of a RAM chip 62256-621024,you can
use 61256-611024.These mikruhi
stand on IBM compatible machines in ka-
honor cache memory. Yes, and there is a burnt mother
3 UAH And one microcircuit is 62256-8 UAH
621024-21 UAH. So draw your conclusions. Nap-
My example costs 61256 and everything is OK.
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