The shared data. This lives in the Hub and can be read and written to by any process in any cog, so long as there's a pointer to it. I just want this to be read/written by three processes. One is turning reads from the PSX controller into data that'll go here. The other process is reading this data to send as an emulated PSX controller to the PS2 console. The third process is a cog running as an I2C slave. This process can either read this data or write to it. An Arduino (or any other thing) could sit on there as an I2C master, read the data, run some numbers and then write data back.