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Installing a Sideways RAM Board in the BBC Model B

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The BBC Model B is one of the most expandable home computers ever made, with a wide range of hardware upgrades still available today. In this project, I'll be installing a Sideways RAM board into my second BBC Model B and using its built-in diagnostic commands to verify that the installation has been successful. Installing the Board Before fitting any upgrade, I always take the opportunity to inspect the inside of the machine. My usual checklist includes: Dust buildup Loose ICs Corrosion Leaking capacitors Damaged PCB tracks Previous repair work Fortunately, this BBC Model B was still in excellent condition. Installing the Sideways RAM board is fairly straightforward. Unlike a traditional Sideways ROM board, this upgrade plugs directly into the 6502 CPU socket , with the processor then fitting into the socket on top of the board. Several flying leads are connected to the motherboard to provide the additional control signals required by the board. Although the installation isn't...
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Programming and Installing New ROMs on a BBC Model B

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In my previous post, I installed a Sideways ROM/RAM board into my BBC Model B. That upgrade gave me several additional ROM sockets, allowing me to expand the machine with extra software without constantly swapping ROM chips. It also gave and extra 32k RAM. Now it's time to put that upgrade to good use. In this guide, I'll be programming two ROMs that I think every BBC Model B owner should consider installing: Advanced ROM Manager (ARM) – a powerful utility for managing your Sideways ROM board and Sideways RAM. BASIC Editor (EDIT) – a much friendlier editor for writing BBC BASIC programs. I'll be programming both ROMs using my TL866II Plus Universal Programmer and XGpro  software before installing them into the BBC Micro. Finally, I'll demonstrate one of ARM's most useful features by switching between the original Acorn DFS and Turbo MMFS filing systems. What You'll Need For this project I used: BBC Model B Sideways ROM Board Two AT28C256 EEPROMs ...
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Installing a Sideways ROM Board in the BBC Model B

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The BBC Model B is one of my favourite retro computers. Even over 40 years after its release, there are still plenty of upgrades available that make using it even more enjoyable. One of the most useful upgrades is a Sideways ROM board , which allows you to install several ROMs at once instead of being limited to the standard motherboard sockets. In this post, I'll walk through installing one into my BBC Model B and show the finished result. What is a Sideways ROM? The BBC Model B stores much of its operating software in ROM (Read Only Memory) chips rather than loading everything from disk. These ROMs can contain things like: BBC BASIC Disk filing systems Utility software Programming languages Diagnostic software As you begin expanding your BBC Micro, you soon run out of ROM sockets. A Sideways ROM board solves this by providing additional ROM sockets, allowing multiple ROMs to remain installed at the same time. Why Install One? Although the BBC Model B is an inc...
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Op-Amp Series – Part 7: The Differentiator Amplifier

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The Differentiator Amplifier Final Build A differentiator amplifier is an operational amplifier circuit that produces an output proportional to the rate of change of the input signal. Instead of amplifying the voltage itself, it amplifies how fast the voltage is changing. In simple mathematical terms: Vout = -RC × (dVin/dt) This means: If the input changes slowly → small output If the input changes quickly → large output If the input is constant (DC) → output is zero Why is that powerful? Because many real-world systems care about change, not steady values. The Basic Differentiator Circuit Basic Circuit A basic differentiator uses: One capacitor One resistor One op-amp Key layout: Capacitor in series with the input Resistor in the feedback path Non-inverting input connected to ground This is almost the reverse of the integrator circuit. How the Circuit Works Let’s break it down conceptually. The capacitor allows current to flow only when the input voltage is changing. The faster the ...
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