External AV / Serial / Joystick ports. DC Socket. 2.5" IDE / Compact Flash adapters etc

To keep the track complexity down on the mainboards, I routed all signals off to header pins and made seperate boards for the real external connectors. There isnt much in the way of electonics on these PCBs. I used mini DIN sockets for the video out (8 pin) and serial port (4 pin), avoiding the usual 6 pin types used for keyboards. The joysticks are standard Atari 2600 D-plugs which unfortunately is the same connector and gender as used on PCs for the serial COM ports but I dont think anyone is going to mix them up :)

For simplicity the audio/video connector board (inset) has a latching multipole mechanical push switch that allows selection of external video or the laptop's own LCD. The sound output is also switched mechanically using the switch-over contacts of the serial jack socket.

The larger PCB has the serial port socket, dual joystick ports (a diode OR with select line allows simple multiplexing of the same 6 control signals) and on the right is the DC power jack. This connects to the 3Amp 7.5V adapter that came with the PSone LCD - handy that. As the FPGAs prefer a smooth power up, I made a "soft-power" system using a SMD PIC and power MOSFET - the output goes directly to to the LCD and the various voltage regulators (5V, 3.3V, 2.5V) for use throughout the system. (The regulators are linear types but as the drop out is quite small, they dont get particularly hot.)

The lower picture shows the main power board (most of the regulators are SMD types on the solder side underneath). There's also an (experimental) MMC connector made from an old PC floppy drive connector. The two green boards left and right are off-the-shelf IDE adapters, the left is for 3.5" to 2.5" drive and the right is for 3.5" to Compact Flash. Naturally it'd be more elegant to get the actual connectors and make an all-in-one PCB but at the time I couldn't find them available and I had these adapters spare.