Category Archives: MCU

Thing to know: Z80 CPU clock

I just only want to send notes to myself. Z80 CPU clock must be 5Vpp and pure TTL levels sometimes are too low for good and stable CPU work. Even this old CPU is very stable at 5Vpp clock, meanwhile … Continue reading

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ZX Spectrum inside CPLD

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

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Testing Commodore 6526/8520 copy in CPLD

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

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AVR USB printer device and teletype

I have old teletype printer T-63 (it is made by RTF in Eastern Germany, clone of old Siemens Teletype). And the idea is about connecting it as USB printer to our-days computer. Easiest way is to connect it using RS232 … Continue reading

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Building 8bit ATARI test ROM in easy way

I was experimenting with damaged Atari 800XL and I need to test it in low level. I wrote several lines in machine code and it was pain in the ass to fill data to ROM chip. After entering HEX data … Continue reading

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