Re: Toggling GPIO at 38Khz

From: Bodo Eggert
Date: Wed Oct 08 2008 - 08:04:41 EST


Jon Smirl <jonsmirl@xxxxxxxxx> wrote:

> I'm working on getring the LIRC IR subsystem integrated into the
> kernel. One common IR hardware implementation is based on standard
> serial ports. It uses the serial port's DCD and DTR as GPIO pins.
> This common IR hardware does not have a transmit modulator and is
> modulating the IR signal in software. Luckily is has hardware
> demodulation.
>
> There are four common IR frequencies - 36Khz, 38Khz, 40Khz, 56Khz. I
> need to create these frequencies in software. Data is then transmitted
> as 400-600us burst of these frequencies. Around 10-30 clock pulses.
[...]

The ALSA PC-Speaker sound driver might do something similar ...

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