This post gives a short overview about the RLV12 Emulator. There are two versions, one for my PDP-11/Hack and one for normal Q-Bus systems. It plugs into the backplane of a PDP-11 system and emulates a 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.
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.