i have made nostalgic project on weekend as i have some boards with 8080 cpu, now i can give them new chance

not sure if all commands were encoded correctly - have no time to test it well, but first "hello" already works on emulator

as well as most home-made pc-s with 8080 in USSR were using koi7 encoding - i have add macro to translate strings from win1251 into koi7 - other men may just ignore it

-------------

errors fixing started

nice

cute

some testing provided, some errors were fixed. further updates (if they will be) will be placed there (to not update everywhere )

now, as i have restored some of my work from cassetes, you may puzzle a little with my forth for i8080 it left unfinished, but can do something - see emulator screenshot

ha ha, very nice

so, i'm already winner?

shoorick,

Get your prize at www.42.com

shoorick,
A winner @ what?

a 3kb demo



similar on emulator:


used hardware:
http://picasaweb.google.com/shooricks/bDnQfG

shoorick, that demo is great!

BTW, do you have some schematics explaining what each chip is? Where is the video output?

yes, there are some variants of schematics of this computer. unfortunately all descriptions of it are in russian - it was presented in USSR in 1987 (developed in 1985 by amatour Wolkow) and was popular here as some other similar, until they were forced out by ZX Spectrum clones. such computers were based on soviet i8080 clone and, i think, are unknown on the west

it has such parameters:
0000-BFFF - 48 kb RAM
including
9000-BFFF - 12 kb video RAM
video: only grafic 384x256x1

C000-EFFF - ROM (this part varies on model)

i made it in 1989 and it was my first PC, been working hard till 1998, and used to play till 2000. unfortunately, it was occasionaly burned, so i made a new one this year as i've been missing it too much (i had a spare PCB for it)

LocoDelAssembly
generally, you may see here original schematic of this computer:
http://www.spetsialist-mx.ru/schemes/Spetsialist.png
its name is "Specialist" (or "Fachiwec" in Ukrainian)
all chips are simple logic, counters, decoders etc. all of them have western analogs and mostly have modern variants, but some of them are archaic, like i8212 register or 3216 bus drivers. large chips are:
i8080 - CPU
i8255 - PIO
2716 - 2kb EPROM (minimal configuration required only 1 eprom - "Loader", but mostly there were 2 eproms used - second was "Monitor" - a simple program which let to operate computer: provide memory modifications, dumps, etc., and handy interface to save or load files from tape)
4116 - DRAM 16kx1 (many clones, as mine, were using 4164 instead)
also, instead of curly western designation of logic in USSR all logic was designed as rectangles with mark inside: & - AND, 1 - OR, =1 - XOR.
tell me if you need more info

regards!

Thanks for the info shoorick, very good.

Unfortunately, I'm still unable to figure out what is responsible for the video output and where is the video port.

simplified explanation:

there are counters which counts from 0 till ... (do not remember last number now) - these numbers are using to generate current video address.
DD8,DD2-DD5

there is a dispatcher, made on trigger DD12.1 and some logic, which let to read byte from memory into storage register DD46 between memory access by CPU. this video reading also provides transparent memory refresh (no delays to CPU by video access).

videobyte from register DD46 goes to registers DD47,DD48, where is shifted by the 8MHz clock and gives out video bits (DD48, pin10).

there are some logic rightside of the counters which generates vertical and horizontal synchro pulses and blanking: DD10 - vertical sync, DD11 - horyzontal sync. rightside of them you can see mixer made on resistors and diodes, which gives composite video through capasitor C4 (ВИДЕО = VIDEO)

an INTEGRATED PACKAGE for i8080 uploaded to WinAsm Studio download area

it contains:
- minimized WinAsm IDE
- minimized fasm
- minimized emu
- minimized docs and examples
- ready to use: unpack to C:\spec and use

is it hard or not - see there:
http://www.youtube.com/watch?v=47KEB57zonk

moved into the new topic