mbed VGA Console

What is it?

The fusion of "Component-less VGA?" (modified to use PWM and I2S) and "mbed PS/2 Keyboard?" (modified to use SPI). Note that as a result of the modifications, the pinouts are different from the referenced wiki pages.

Pinout

KEYBOARD
========

Looking into end of PS/2 keyboard *plug*:


             nc --->   o  o   <--- mbed(7)/MOSI
 
 VCC/mbed(63) --->   o      o   <--- mbed(1)/GND
                        ||
            nc --->   o || o   <--- mbed(9)/SCK

VIDEO
=====

 MBED-DIP64 Pin               VGA D-15 Pin

  1 / GND*      ------------>  4, 5, 6, 7, 8, 10, 11 / Signal, sync and shield grounds

 11 / PWM6      ------------> 14 / Vertical-Sync

 13 / PWM4      ------------> 13 / Horizontal-Sync
                    ____
  1 / GND*      ---|____|--->  1 / Red-Signal via 240R
                    ____
 17 / I2STX_SDA ---|____|--->  2 / Green-Signal via 240R
                    ____
  1 / GND*      ---|____|--->  3 / Blue-Signal via 240R


* at present, even though they *should* be, these pins aren't
  actually connected and instead rely on a ground loop from
  the USB connector, through the host PC back to the monitor :-)
  This only works because I'm using a twin-input monitor and
  the other connector is driven from the host PC -- don't try
  (and definitely don't rely on) this at home.

+ R & B resistors are obviously optional, but left in, just
  in case -- could be wired to GPIO near I2STX_SDA in order
  to allow a lower resolution eight colour graphics mode;
  alternatively one could be wired to the other muxed
  I2STX_SDA output in order to facilitate, for example, the
  choice of green/blue/cyan, red/green/yellow,
  red/blue/magenta, or paired to produce red/cyan/white,
  blue/yellow/white, green/magenta/white on a per-pixel-line
  basis; or maybe, on a good day, at fixed column positions.

Here's the video!

I type faster than this normally :-)

enjoy!
Simon.