1) Try the DMA mode in joan's pigpio library, you will need a large buffer, and you will need to move the bits around, but it may be possible.
2) Add a USB microcontroller to do the hard real time data gathering, and if it has high speed USB, have it send it to the Pi in batches
3) Pester the Raspberry Pi Foundation to release documentation on the "Secondary Memory Interface" which is available on the Model A+/B+/Pi2 40 pin GPIO connector, then we can all play with high speed I/O
I, and others, have asked for documentation, and the responses have been "maybe later"
I even tried to get docs from Broadcom, they told me to ask the Pi Foundation for it.
mdavister wrote:A lot of what I've seen about the PI is on the order of "fun" or "neat" applications. I want to do something useful with a PI, moving data around and controlling some signals. Is it possible to get higher bandwidth I/O on a PI type computer? I'd like to be able to toggle some IO pins at least above 20 MHz, and be able to move data at about 11 MB/s from the outside world into the PI. Is this even possible? I have read through the specs a bit, and it appears the processor is quite capable, but the outside world is accessed through GPIO for the most part. Other processors are a great deal slower when running over GPIO.