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Stuff what I did

Posts Tagged ‘Hol-1’

Blinken Hex Lights —

Time to upgrade some of my binary Blinkenlights plug-ins to 7-segment LED hexadecimal versions. In the design of my Hol-1 8-bit CPU I have been leaving rows of pin headers for the attachment of LED indicators. Mainly because you can never have enough Blinkenlights twinkling on a homebrew computer but also because they have their […]

8-Bit CPU – MMU —

A Memory Management Unit for my 8-bit “Hol-1” CPU Why an MMU? An MMU controls a computer’s memory. On a larger more complex CPU this would involve ‘virtual memory’, security and the fine-tuning of memory organisation. A clever part of CPU architecture that helps even inefficient software to perform reasonably well. With only 64-bytes of […]

8-Bit CPU – Clock Fix —

Improving the clock signal on my 8-bit “Hol-1” CPU. As my homebrew 8-bit CPU takes shape I find I’m continually fighting temptation to re-design the boards that have been created so far. I realise though that that would be unproductive as no sooner had I created a version 2 of a board then I’d get […]

8-Bit CPU – RAM —

Adding a RAM board to my 8-bit “Hol-1” CPU. What is RAM?: Continuing the build of a simple CPU from TTL chips the next step is the random access memory (RAM). It’s not ‘random’ because it’s haphazard but because you can read/write to any section of memory directly using its address. Historically memory devices had […]

8-Bit CPU – ALU —

Building an Arithmetic & Logic Unit (ALU) with TTL logic. Recap: My quest to build an 8-bit central processing unit (CPU) from transistor transistor logic chips (TTL) continues. This initial venture into CPU design being very much guided by Ben Eater’s video tutorials for a computer built on breadboards. Please refer to Ben’s videos for […]

8-Bit CPU – Registers —

Building CPU registers with TTL logic and some blinkenlights. Recap: Previously I posted about my quest to build a computer’s central processing unit (CPU) from transistor transistor logic chips (TTL). This initial venture into CPU design being very much guided by Ben Eater’s video tutorials for a computer built on breadboards. Please refer to Ben’s […]

8-Bit CPU – Clock —

Building a CPU clock and controller from 555 timers and TTL logic. Update: Please note my later post which contains an improvement to this TTL clock signal generator. Why?: Back in 2015 when I posted an item on Logic Buffers I intended to produce follow-up posts covering common logic chips. Producing each in a simple […]