Ron K. Jeffries wrote: > *You do amazing work. Full stop.* Heh, thanks :)
> Does spi-jz470-gpio only require the UBB board to interface to the outside > world using spi? Yes, and you may not even need a kernel driver for most things. SPI is quite trivial to implement in user space, and we have a library that helps with the tricky bits. > Does your code implement SPI host capability, or SPI slave, or both? Only SPI host/master. SPI slave would be difficult without extra hardware, because the time between chip select and the first bit is usually very short, too short for software to respond reliably. You'd also have to provide a flow control mechanism, etc., and you'd need some of the more advanced trickery for making sure the Ben can reliably keep up with the data clock, once it has detected the beginning of a transmission. Things are a lot more relaxed if you're the master. There, you only need to worry about any speed limits of the device, and in many cases, these constraints are beyond what software could exceed anyway. > Bottom line, for $25 (Model A no Ethernet and 1xUSB) or $35 (Model B with > Ethernet and 2xUSB) it's a low cost way to provide internet connectivity to > a Ben NN when at a fixed location. RPi as SPI-based IO extender for the Ben. Certainly sounds feasible. With hardware-assisted SPI, the RPi should have no trouble keeping up with the Ben. Seems that you've found yourself a project :-) > p.s. Counting down time until someone tells me to shut up and buy a Ben Well, you'll kinda need one for this project, even if it's only for pictures showing the two happily united ;-) (You can of course do the prototyping with a pair of RPis, or possible even with just one, talking to itself.) - Werner _______________________________________________ Qi Hardware Discussion List Mail to list (members only): [email protected] Subscribe or Unsubscribe: http://lists.en.qi-hardware.com/mailman/listinfo/discussion
