Monthly Archives: March 2020

AM modulation, schematics, lots of transistors and perfect modulation

I was testing various AM radios and noticed, that I don’t have proper AM source. The AM broadcasting station in my region is very scarce and weak. Also, I wanted more options for radio receiver testing. I though, that the … Continue reading

Posted in Anything | Leave a comment

Simple Sinewave generator

There is simple and good way to generate quite pure sine wave: This circuit is not very simple, but results are quite fine: output is pure sine wave. From the other side, this schematics have some minuses: it is hard … Continue reading

Posted in Anything | Leave a comment

ZX LCD

After building ZX Spectrum clone in CPLD I ported hardware code to another project and this is a bit simplier, but it uses some mono LCD from old copy mashine. Now I used only one CPLD, but I added additional … Continue reading

Posted in Anything, FPGA | Leave a comment

Cartridge for Commodore 64

Sometimes I want to show how old 8 bit computers work for some n00bs. It is nice to load some game from tape, some from disk. But when I want to show more game, best thing is cartridge. And not … Continue reading

Posted in Anything | Leave a comment

ZX Spectrum inside CPLD

I found old ZX Spectrum clone made in Soviet Union in 90′s. It was my computer, I wrote several program on it and also, I wrote drivers for Espon printer on this hardware. This model has Soviet chip КР580ВВ55А (Intel … Continue reading

Posted in Anything, FPGA, MCU | Leave a comment

Fancy soldering

Good fellow donated my collection with new item- Sharp PC-2500. The only big problem- this old computer had caustic batteries inside and they leaked. Alkaline used in the batteries has very ugly feature- it can travel under conformal coating along … Continue reading

Posted in Anything, Vandalising | Leave a comment

Testing Commodore 6526/8520 copy in CPLD

There is quite expensive obsolete chip from various Commodore computers and peripherials- CIA/PIA MOS 6526 and a bit changed 8520 used in Amiga computers. This is “complex” peripherial interface adapter chip for 6502 processor or 68K chipset. It is quite … Continue reading

Posted in Anything, FPGA, MCU | Leave a comment

My collection of old computer

For a long time, I collected small collection of computer hardware. Here is the link to my Old Bits Collection.

Posted in Personal | Leave a comment