Soekris net4501 GPIO on FreeBSD 7.0
Posted Sun, 06 Jan 2008
Since my Soekris box is now free of it's router duties, I can use it for this project. To do this, I'll need two pieces: an infrared receiver, and an infrared emitter. I bought an infrared emitter led today, and I just need to buy a receiver online (they're like $2).
Before getting there, I needed to learn how to drive the GPIO ports on the net4501.
It was pretty simple to do, nd after hooking up a few wires I had an LED that blinked after a few hours of reading and hacking. The code itself was trivial to write, I just had to learn how to talk to the GPIO ports.
After writing the blinking code, I decided the next step was clearly to add fading to the LED. This is commonly done with PWM (pulse-width modulation). Apple made this technique famous with its "breathing" LED lights on the monitors and laptops when the devices were in sleep mode.
At any rate, I have successfully written code that makes both the error led and the PIO5 (GPIO 0) pin "breathe".