Raspberry Pi - how to load RAM programmatically through SD interface?

Question

I would like to have some kind of mechanism to somehow load the RAM on the Raspberry Pi programmatically from a controller computer (I assume through the SD interface) and then let the Raspberry Pi's CPU execute. Is there some kind of device that does this? And what is it programmed in?

It would also be great if there's a way to interrupt the whole thing from the controlling computer if needed.

Answer 1

SD is a fairly poor choice for an interface to try to push data into from an external source; generally the computer hosting the SD device wants to be the master of operations.

But the Raspberry pi has both uart serial ports and (on the model B) an ethernet interface. Downloading code through either is quite normal.

You haven't mentioned if you want to run an application atop a typical linux installation, or if you want to do bare metal programming. In the first case you would typically transfer the program to the file system (either ramdisk or the SD card) and then execute it.

In the second case, you would need a stub of code already on the device (which is to say, the boot partition of an sdcard) which knows how to configure peripherals sufficiently to enable reception of code via serial or ethernet (the latter complicated by needing a USB host stack), and then jump into it.