Moving AGAT-7 retro-computer project to the “Retrobyte” platform
As you may remember, I’ve designed a universal platform for building retro-computers, “Retrobyte”. I successfully tested it by creating the “Mikro-80” computer a few months ago, and now I’m working on adapting my other retro-computer project “AGAT-7”, to this platform. …
Computer “Mikro-80” – a modern replica
The computer “Mikro-80” was made in the Soviet Union in 1980 by a team of enthusiasts. In 1982 the magazine “Radio” began publishing its documentation and schematics. This was the first accessible personal computer in the USSR; in that era, …
Retrobyte Rev.B
In my previous post, I explained my idea of a modular platform for building modern replicas of retro-computers, of which the Rev.A has already been built and tested. In the process, I found a few things to improve: On the …
Retrobyte – a universal modular platform for building replicas of retro-computers
While working on the “Agat-7” replica, I came across the need for constant changes and improvements; these resulted from either new ideas or troubleshooting. Some of these troubleshoots involve tinkering with the circuit board. I have four different revisions and …
AGAT-7. Rev.0 summary and start of Rev.A design.
I’m finalising my Rev.0 of the modern retro-computer “AGAT-7” replica. The next step will be Rev.A design with fixed mistakes, improvements, and new ideas. In this post, I’m going to summarise the Rev.0 experience and share with you some ideas …
Clock generation in FPGA with phase accumulator. Calculation and limits.
In my project of a modern replica of a retro computer, “Agat-7”, I needed to generate several clocks. The PLL built-in FPGA can produce some of them; others are a simple division of the main clock. But another group of …
Agat-7. Rev.0. CPU, memory and joystics
Let’s go to the following part of the schematic. Today it is the CPU, the SRAM and the joysticks. Here it is: “Agat-7” has 96Kb of RAM, so we need a 128Kb SRAM chip. We can use 128K x 8bit …
Agat-7. Rev.0. Floppy-drives emulators.
At the moment, I’ve completed the schematics, and I’ve started to work on the PCB layout. There will be some changes caused by discovered mistakes or better layouts. So, please, treat it as a draft at this stage. Please, let …
Agat-7. Rev.0. Video output.
I’ve spent some time debugging STM32L based 140K “floppy drive” for my “Agat-7” replica project. It is already perfectly workable in read-only mode. I transferred it to the SPI interface to save some FPGA pins, and now I need only …
HD44780-compartible LCD display and STM32.
HD44780-compatible LCD digital-alphabetical displays are very convenient to use in hobby projects. They exist in different sizes and are quite cheap. The most popular are 2 line modules with 16 characters per line (16×2). Also, 8х2, 16х1, 20х2, 20х4 and …