Радио 86РК (Radio 86RK): Part 3 (Loading Cassette Software) [TCE #0487]
30Thanks again to #PCBWAY for supporting this project! It's their 10th anniversary in July - check out their activities here:
https://www.pcbway.com/activity/anniversary10th.html
Now ... let's try some games out by loading them via the cassette port. The cassette port only needs three pins (tape in, tape out and ground) but actually is an 8-pin DIN. I didn't have one of those handy, but 5-pin and 7-pin DIN plugs are also compatible.
To load the games I used MAME's castool to convert some RKR-format files to WAV files, then played them back at 60-70% volume using Audacity.
I obtained the RKR files from the Radio 86RK section here:
https://github.com/alemorf/retro_computers
I tried out PACMAN, TAPPER (BARMEN), XONIX and LODE RUNNER.
I did originally use video capture of the computer output but it seems to be variable framerate ... I couldn't capture directly so had to go via my Sony DVD recorder first and then to my Elgato USB analogue capture device.
I spent a few days just trying to get it in synch with the overhead video of the computer taken on my iPhone (25fps) ... some sections I could synch (50fps to 25fps by speeding it up 200%) but then other parts would be out of synch. Argggh.
So, apologies, I just filmed the display.
If there's interest, I could do just a pure gameplay video ... there's quite a few available.
From Part 1:
The Radio 86RK was an early Soviet home brew computer (not the first) designed around their version of the Intel 8080, the КР580ВМ80А. It is named after the magazine it was featured in, РАДИО (or RADIO), with the РК (or RK) standing for "Радио Компьютер" (or radio computer), indicating that it was targeted at ham radio enthusiasts, similar to the use of a "ham shack" computer in the West.
It was then used as the basis for a range of industrially produced computers, such as the Партнер 01.01 (Partner) and Альфа БК (Alpha BK) already featured on this channel, which provided a case & keyboard, as well as saving the builder from trying to source scarce parts on their own.
This isn't an original build but Sergey Kiselev's updated version - I'm using v1.3 of his board which requires 2716 (2KByte) EPROMs still and uses the quirky JCUKEN keyboard layout.
He has created a v1.4 that allows larger/newer EPROMs to be used as well as switching to the more familiar QWERTY keyboard layout.
https://github.com/skiselev/radio-86rk
Getting a hold of the parts wasn't too difficult - I sourced the older ones from Unicorn Electronics in the US (as suggested by Sergey).
https://unicornelectronics.com/
Shout out also to Adam (@adamradipat1715) for sending me both a Polish and a Soviet 8080! As I progress with this machine, I'll try to swap out as many of the Western parts for more authentic Eastern Bloc parts as I can.