Elwro 800 Junior
Good Polish descripion of hardware can be found in
Informik I/1989 s.20..26 (see files for download below).
Ports:
- #1F - 8255 PA (joystick shadow port),
- #BE - 8251 (Junet - data),
- #BF - 8251 (Junet - control),
- #DC - 8255 RS,
- #DD - 8255 PC (7-strobe, 2-ack),
- #DE - 8255 PB (printer data),
- #DF - 8255 PA (joystick),
- #EE - FDC 765A status,
- #EF - FDC 765A command and data,
- #F1 - drive selection,
- #F7 - memory configuration (a bit odd),
- #FE - border, buzzer and tape,
- #xxFE - keyboard reading,
- #xx7F - extra keyboard port,
- #xxFB - extra keyboard port.
Memory map
| Addresses | Memory bank |
| #E000..#FFFF | RAM | (CP/J screen) |
| #C000..#DFFF | |
| #A000..#BFFF |
| #8000..#9FFF |
| #6000..#7FFF |
| #4000..#5FFF | (ZX screen) |
| #2000..#3FFF | ZXROM
(BASIC) | |
| #0000..#1FFF | FDC ROM |
Keyboard ports
| Port sddress | Bits |
|---|
| 7 | 5 | 4 | 3 | 2 | 1 | 0 |
|---|
| #FFFB | Ż | Ć | LEFT | RIGHT | UP | DOWN | DIR |
|---|
| #FF7F | ˇ | Ń | ¬ | Ł | ¦ | Ó | Ę |
|---|
| #FEFE | +
; | *
: | V | C | X | Z | SHIFT |
|---|
| #FDFE | {
[ | =
- | G | F | D | S
SAVE | A |
|---|
| #FBFE | <
, | >
. | T | R | E | W | Q |
|---|
| #F7FE | \
@ | ?
/ | %
5 | $
4 | #
3 | "
2 | !
1 |
|---|
| #EFFE | }
] | DEL | &
6 | '
7 | (
8 | )
9 | _
0 |
|---|
| #DFFE | BS | ESC | Y | U | I | O | P |
|---|
| #BFFE | SHIFT
LOCK | TAB | H | J
LOAD | K | L | CR |
|---|
| #7FFE | -
^ | CTRL | B | N | M | ALT | SPACE |
|---|
Junet network
Is based on 8251 USART. Serial input and output are connected together as open collector. Transmission is clocked at 54687.5Hz (14MHz divided by 256). For slave units clock signal is provided externally.
Attribbutes buffor
An interesting solution is the attribbutes buffer. Informations about colors are not taken directly from screen memory, but from additional 1kB memory. So switching the screen requires also rewriting its attribbutes.
Files for download
- proms.zip 3.1kB (2006-01-29 15:09)
- Content of PROMs used on Elwro 800 Junior board.
- i89-1-20.html 38.8kB (2006-01-22 13:02)
- [pl] "Mikrokomputer Junior -- pamięc dyskowa." Article in Informik I/1989, by Władysław Strugała.
- i89-1-21.html 11.7kB (2005-10-23 03:32)
- [pl] "Elwro 800 Junior." Article in Informik I/1989, by Tadeusz A. Zaleski.
- cpu800j1.gif 612.5kB (2005-10-22 23:20)
- The CPU E-800 Junior schematics, page 1Z. 6700×4700. CPU, address decoders, ROMs, 8255 (printer, joystick), 8251 (Junet).
- cpu800j2.gif 731.2kB (2005-10-18 00:06)
- The CPU E-800 Junior schematics, page 2Z. 6700×4650. RAM, video generator, #FE port.
- fdc-800j.gif 560.2kB (2005-10-16 21:48)
- FDC module schematics. 6700×4800.
- roms.zip 18.2kB (2005-02-08 15:41), uploaded by DDX
- ROM of Elwro 800 Junior. (Not useful with ordinary ZX Spectrum emulator.)
- matemat.zip 239.8kB (2003-10-08 04:01)
- [pl] Some Junior software. Disk in MV-CPC format. Some files are corrupted.
- elwro.jpg 57.6kB (1999-06-12 22:46)
- With tape recorder, printer and monitor.
- elwro.html 30.6kB (1999-06-03 00:02)
- [pl] Hardware description by Powolniak.
- elwro03.jpg 60.5kB (1999-04-07 02:21)
- FDC board top view.
- elwro02.jpg 90.4kB (1999-04-07 02:21)
- Main board top view.
Links to other pages- http://www.vintagehomecomputers.com/c.asp?14
- Vintage Home Computers, short description.
- http://www.vulcan.edu.pl/biuletyn/bi24/04jakpowstawalyprogramy.html
- Elwro 800 Junior and Vulacan company.
- http://cysio.dyndns.org/8bit/elwro800jr/
- Schematics files, ROM files, DSK files and Total Commander plugin.
See also
- 22DISK
- File copier for CP/M disks (MS-DOS). 22DISK by Sydex.
- QTRANS
- Manages Disk Objects - disk drives, diskimages, files on them, partiton tables, etc. Creates, removes, copies, renames anything you want.
- Emulator Elwro 800 Junior : VJUNIOR
- Elwro 800 Junior emulator. VJUNIOR by Vulcan, new emulators written in C.
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