[BRLTTY] chicken and egg situation

[Jason White]

David Pankhurst <dave at pankhurst.com> wrote:
> Hello - I have a question about developing Braille readers - how
> does one start?  It seems that without the device, there can be no
> driver, but without the driver, how can one design/test/configure
> the device? 

I don't understand the problem, so perhaps if you can explain it a little
better it will be easier to solve.

If you want to design new hardware, then surely you have reviewed existing
products and the research literature, and you have some notion of how your
device is meant to be different from what has been designed already.

If you can then design the device and build a prototype, you should then be
able to write the firmware for it, which requires you to design the protocol.
You can then write a driver, though I think it is more likely that you would
develop and test the driver and the firmware together.

Some braille devices have test routines built into the firmware, so you don't
need any driver or any connection to a host system in order to perform basic
hardware testing, e.g., raising and lowering all of the pins in sequence.

I don't have any background in hardware design, but it seems to me that the
hardware design would come first, at least until you have the first prototype,
then the firmware and the driver would be written, then you test it and modify
the design as required.