Inspired by Oscar Vermeulen's emulations of PDP8 and PDP11 front panels (I've used both processors, in my time over the past 40 years) but as yet inexperienced in the RPi world (despite getting Pi1 2 years ago and Pi2 one year ago :-( ), I'd like to consider producing a similar front panel low-level access for the RPi itself.
Is anyone aware of direct digital I/O facilities for the RPi, ie, in not going via the I2C bus?
Or, even an I/O bus creation facility, perhaps much along the lines of the PDP8's Omnibus?
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Also, what of interfacing a hard disk into the SD card slot.?
Apologies if I have posed these questions before, for it always takes me many months to come to a definite decision; never put off till tomorrow what you can put off till the day after :-)