robots.net blog for svo

Strobeshnik

Sat, 6 Mar 2010 23:10:06 GMT

Strobeshnik is a stroboscopic digital clock made from an old HDD.

Strobeshnik project writeup

A Nixie Clock in A

Thu, 18 Feb 2010 14:15:44 GMT

The incredibly compact IN-14 based nixie clock in a Marine Band harmonica case. It shares the same code as my previous clock, Satashnik. The circuit is mostly the same, except that it's changed for IN-14's and made to fit in the tight space of harmonica case.

Eagle stuff is here.
Source code: Harmoshnik updates follow the Satashnik tag. This time I've had a chip that needed some serious calibration for its RC oscillator, the code update is mostly about that.

Satashnik

Tue, 26 Jan 2010 23:15:15 GMT

The IN-2 Nixie Clock is complete. This is a very compact clock, too.

Project writeup

What's cooking...

Mon, 18 Jan 2010 02:14:42 GMT

New, multiplexed design with only one ИД1 and unique tunnel-vision ИН-2's.

And BTW, IN-2 footprint was updated in the library. If you started a design already, update before it's too late.

Link: [lbr] (click View Raw File to download the lbr)

Eagle CAD library with Russian Nixies

Wed, 16 Dec 2009 02:18:21 GMT

A library with Russian nixie tubes. This .lbr includes: IN-2, IN-8-2, IN-14, IN-17. Only IN-8-2 is verified by a working design so far.

Библиотека с индикаторами ИН-2, ИН-8-2, ИН-14, ИН-17. Пока только ИН-8-2 были проверены работающей схемой.

Link: [lbr] (click View Raw File to download the lbr)

Никсиклок «Паташник»

Fri, 11 Dec 2009 16:11:46 GMT

Часы на газоразрядных индикаторах ИН-8-2 «Паташник» с высокоточными часами реального времени DS3234.

"Patashnik" is a nixie clock with DS3234 RTC.

Patashnik

[M]ouse connects a PS/2 mouse to Commodore 64

Sat, 14 Nov 2009 00:13:17 GMT

This adapter lets you plug a PS/2 mouse in a C64 and use it with mousing graphics editors or GEOS. It emulates both propoprtional (analog) and joystick modes of Commodore 1351 mouse. Full schematic and source code available.

[M]ouse: project description and downloads

Hacking with Style: TrueType VT220 Font

Wed, 14 Oct 2009 00:05:31 GMT

I spent some time looking around the net to find a font that mimics DEC VT220 terminal glyph appearance. There is none. There are some old bitmapped fonts from X11 and probably early MacOS distributions that claim to be DEC fonts, they are functional but their visual quality is lacking and nostalgic value is absent. What I wanted is a font that fills my virtual terminal window with the magic hacking glow...

Font and making How-To

Фонт и краткое описание технологии

Цветной композитный PAL-выход для Altera DE1

Mon, 28 Sep 2009 23:08:51 GMT

Накладки во время cc'09 сподвигли меня на реализацию кодера композитного видеосигнала для vector06cc. Небольшая заметка о том, как это было сделано. Без особых подробностей, скорее не руководство, а чтобы самому не забыть. Но вдруг кому пригодится:
ПАЛ-кодер на Altera DE1

Problems with nonstandard VGA output on my Vector-06C FPGA replica made me implement composite PAL output. DE1 board has enough resources to throw in full-colour PAL signal without any additional components. R,G,B wires of VGA output are connected together to cope with 75 ohm load, the rest is done in verilog. This short writeup is Russian-only because there seems to be enough PAL-related info readily available in English. All source code is available in the main vector06cc source tree.

T80 Core To Be The Most Precise 8080 To Date

Wed, 23 Sep 2009 22:15:44 GMT

8080 Emulation Quality

8080 has many dark corners. Unlike its more popular successor Z80, 8080 had never been studied enough and most emulator code, and FPGA cores, relied on data from various books and often even word of mouth. Thusly, it's known that DAA instruction doesn't yield correct result after subtration but it's not known why and AC flag has mysterious ways too..
Just recently a few enthusiastic people from a Russian Vector-06c fans forum found a piece of software for Vector-06c which could not be started in any of the existing emulators, couldn't be started in my FPGA replica yet had no problem running in the real Vector-06c at all. After some investigation it turned out that 8080 ALU had AC flag inverted after SUB operation. This involves SUB, SBB, SBI, DCR, CMP, CPI instructions. The pesky ware used the contents of 8080 flags register as a branch address. Ultimately it led to this discovery of auxilliary carry anomaly.

While fixing this issue in the T80 core, which I use in my Vector-06C replica, I discovered a lot of other discrepancies with the original CPU. Thanks to the ultimately inquisitive CPU test written by Ian Bartholomew, 8080 Exerciser, I was able to verify my version of T80 against the baseline set by the real CPU in a real computer.

Probably not an earth-shattering news, but this is a milestone in emulation of 8080 CPU nevertheless. As of now, there are no known tests that could tell my version of T80 in 8080 mode from the real thing. Update your emulators or you're going to lose the edge :) Only my version has these changes at the moment, they had not been merged with the "official" opencores.org version.

One thing worth noting: real CPU tests were done on a KR580VM80A, which is known to be a gate-level clone of 8080, but still not exactly the real thing. If you have a real 8080 CPU computer which can run CP/M 2.2 or similar, please try Ian's test on your computer and send the results to him or to me.