This post gives a short overview about the RLV12 Emulator. In the meantime there are many versions. There are versions for my PDP-11/Hack and version for a normal Q-Bus system. It plugs into the backplane or Q-Bus of a PDP-11 system and emulates an RLV12 controller with 4 RL01/02 units attached.

A PDP-11 is more fun to use, when you have more memory, especially when your system supports 22-bit addressing. Therefore I decided to build my own PDP-11 Q-Bus memory board.

This is a short resume about my Plessey Peripherals PDP-11. Or let’s say about the remains of the system which for a long time was just a play ground and today I could revive it as a fully functional PDP-11. Even only the core is of the original system, adding new components for the surround still let’s you experience the real look and feel of a small PDP-11.
Update 2020 New Power Entry Module

This is a study how to read and write Floppies without a floppy disk controller. I developed two solutions. One is a pure software solution running on a AVR processor and the other is a MFM de/encoder using a small CPLD

Once you have mastered reading a floppy the next step is writing a sector

Instead of counting cycles a far better approach is to use a timer. Here is now a MFM write sector routine that uses a timer to create the write pulses.

Over the years I have changed the way I develop my applications especially how I create programms for my Atmel MCUs. After many detours I have decided to no longer use the Microchip IDEs

I often have the need for prototyping certain features or ideas using either a CPLD or an MCU. I mostly use a breadboard for this purpose. Howeveer when it comes to use a CPLD you need some sort of adapters. After using several off the shelf universal adapters I decided to build my own adapters