Robotron 1715 unofficial support

Here is unsorted info
..mostly digged out from forums, especially german ones.

"I'd better learn german
To read this forum normal"
(Mayakovsky)

"Немецкий я б выучил только за то..
...Но, впрочем, забью и не буду"

202109
Here at Chriss.fun Igor builds (AND SALES!) a-heap-of AVRs based compatible clone

201310
here german folks discusses some debug V24/RS232 activity for Robotron without loading os. It's unclear if this requires some specific rom image (looks like that). They say that EEPROMs and RAMs are awfull quality because they are Soviet. And we know there was no good Soviet things except tanks, hockey, rockets and education.

Looks like the ROM test image name is os_v6.bin, and you have to ask for it by private message
Looks like the greatest guy there is called DL

The forum is very interesting, too

тут комрады очень сильно заморочились ремонтом. Говорят что можно замутить какую-то активность на V24/RS232 - только неясно, на родном ROM или на кастомном. Кажется на кастомном все таки. Очень ругают совковые РФки и РУшки. Впрочем, все говно совковое, кроме танков, ракет, хоккея и системы образования.

Кажется название ROM-имиджа os_v6.bin, раздают в привате.
Самого крутого чувака там зовут DL

Ресурс подлежит внимательному изучению!

So, it's a bit clear. STOCK ROM, 9600 8O1 /Yes, 8 ODD parity, 1 (really there is 1.5 stop bit, but 1 works)/
start with 0x11 0x11
You'll get 0x12 0x12
Then,

0x0A

AddressLo

AddressHi

ProgLengthLo

ProglengthHi

[program itself]

(may be 0x11 0x11 /0x12 0x12 handshake once again?)


0xAA

StartAddLo

StartAddHi

Note, that on boot lower addresses are busy with ROM
Here how to read byte from SIO:


    ld	bc,5000
loop:
    ld	a,0
    out	(0FH),a
    in	a,(0FH)
    bit	0,a
    jr	nz, gotit
    dec	bc
    ld	a,b
    or	c
    jnz	loop

(here means we got no char in 5000 iterations)

gotit:
    in	a,(0DH)

Char in a

And here how to write it:


    out	(0DH),a

Here is detailed instruction on V24 booting (click on 1715 image)
Uh, the guy sitting inside very cool! He connected PS/2 keyboard via AtTiny85!

Some interesting page,too. Includes "some basic boot disk somewhere from Russia", hm ;-)
Here guy also speaks about SIO init on bootup, SIO boot!!!! and link to here

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