[mythtvnz] Serial IR blaster on USB to serial cable

[David Zanetti]

On 27/08/2010 11:33 p.m., Robin Gilks wrote:

>> FTDI FT232* USB Serial chip in bit-bang mode is more than capable of
>> doing this. It would be an interesting project to make it work. libftdi
>> may help you in this regard :)
> 
> Drivers... drivers drivers drivers...

libftdi is open, and FTDI themselves provide a driver as well (same API
as their win32 one, the D2XX). And FTDI chips are well supported,
existing kernel code is just fine.

> For external USB stuff I'd prefer an Atmel 8 bit AVR micro doing USB
> decode in software and bit banging the output to the LED - could download
> different modulation code sets on the fly then. Someone still has to write
> an lirc kernel device driver for it though so I'd use either a real serial
> port or a USB MCE remote that has 2 3.5mm jacks in the back for IR
> blasters (I'm using the latter in 2 places!!).

Vastly overengineering it. Bitbang mode on the FTDI does buffering and
correct clocking out of the bits itself, as in, you can dump it a long
sequence in bulk and the chip will correctly clock it out for you.

http://www.huitsing.nl/irftdi/

Looks like someone already did it :) Appears to even manage to work for
reception as well.

-- 
David Zanetti <dave2 at wetstring.net>
http://hairy.geek.nz/

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