Home-Brew IR port. Was - Please Ignore RS232 message. The subject should read IrDA port... Sorry

Joe Pfeiffer jjpfeifferjr at comcast.net
Fri May 11 18:49:44 CEST 2007

Alan Ide writes:
>The IR transmitter I found on LIRC is a home-brew transmitter that is simply
>a serial port device. So if my understanding is correct, LIRC is simply
>sending data at the baud rate of the serial port (19.2 I think) and the data
>itself is modulated to get the desired effect. Thus, we arent taxing the
>driver or the hardware at all, it is simply a one way serial communications
>data stream. As long as we can configure one of the GPIO pins as a serial
>communications port (via the driver interface), this should all work just as
>planed. So either we need an unused serial port, or we need to configure one
>of the GPIO pins to be the TX of a serial port, and we have a functioning

Hmmm....  looks like the three UARTs are all hooked up to dedicated
pins.  TXD0 is on the GSM modem, TXD1 is on the GPS, and TXD2 is being
used as the RTS on the GPS.

A note on UARTs if I'm wrong on the above:  a UART can normally be
configured to many speeds; you'll need to configure it to match the IR
receiver (back when I was playing with IR software on my Palm, it
turned out that not all receivers used the same frequency....  don't
know if that's been more standardized since).

But bit-banging something like IR output really isn't so bad; the message
hooked up to a button press is quick enough that it shouldn't cause a
real problem with interactivity.

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