The Raspberry Pi is nice and all -- it has good CPU power and a GPU, at a low cost and low power budget.
It doesn't have analog I/O, and it doesn't have a good way of reading RC PWM input signals. (Perhaps some kernel module can be cooked up that does it with interrupts, but I haven't seen anything like that.)
I've successfully used Teensy paired with Raspberry Pi for a few years now, and quite like the model. But, you know what would be even better? A Raspberry Pi "hat" that contained the Teensy chips right on it, rather than having to use separate carrier/interface boards.
I know that PJRC sells the special "programmer" chips for tying into the Freescale MCUs. Thus, a "hat" could presumably be built with that chip, and either the Teensy LC MCU (for low cost) or the 3.5 MCU (for 5V tolerance, at slightly higher cost.)
However, if I were to build a few dozen of these and sell on Tindie, that wouldn't really be economical. Meanwhile, if the LC was available as a hat from PJRC -- same board/chips, just a bigger PCB and a 2x20 pin female on the bottom -- that might be reasonably priced. (I'm guessing here -- perhaps the connector and the bigger board would double the price; I don't know?)
Another thing that would be cool would be a version of HalfKay that runs on the Raspberry Pi serial port, rather than USB. (Or I2C, or SPI.) That way, the "hat" would be totally programmable from the Pi without needing a loop-around USB cable. I dislike the USB cables; it's not a robust signalling protocol for things the move and shake, and the cables end up being almost as big as all the other electronics when assembled.
Clearly, it's "possible" to run HalfKay over a serial port, instead of USB, but a more interesting question would be: if I built a dozen boards, would PJRC be interested in selling MKL02 chips that loaded that custom bootloader, rather than the USB-based one?
It doesn't have analog I/O, and it doesn't have a good way of reading RC PWM input signals. (Perhaps some kernel module can be cooked up that does it with interrupts, but I haven't seen anything like that.)
I've successfully used Teensy paired with Raspberry Pi for a few years now, and quite like the model. But, you know what would be even better? A Raspberry Pi "hat" that contained the Teensy chips right on it, rather than having to use separate carrier/interface boards.
I know that PJRC sells the special "programmer" chips for tying into the Freescale MCUs. Thus, a "hat" could presumably be built with that chip, and either the Teensy LC MCU (for low cost) or the 3.5 MCU (for 5V tolerance, at slightly higher cost.)
However, if I were to build a few dozen of these and sell on Tindie, that wouldn't really be economical. Meanwhile, if the LC was available as a hat from PJRC -- same board/chips, just a bigger PCB and a 2x20 pin female on the bottom -- that might be reasonably priced. (I'm guessing here -- perhaps the connector and the bigger board would double the price; I don't know?)
Another thing that would be cool would be a version of HalfKay that runs on the Raspberry Pi serial port, rather than USB. (Or I2C, or SPI.) That way, the "hat" would be totally programmable from the Pi without needing a loop-around USB cable. I dislike the USB cables; it's not a robust signalling protocol for things the move and shake, and the cables end up being almost as big as all the other electronics when assembled.
Clearly, it's "possible" to run HalfKay over a serial port, instead of USB, but a more interesting question would be: if I built a dozen boards, would PJRC be interested in selling MKL02 chips that loaded that custom bootloader, rather than the USB-based one?