IR Interface for an Ethernet SBC

In a previous blog, we looked at a range of ethernet based SBCs. We have also been looking at various IR Remote Control signals. The next step is to bring the two together - to build a circuit to send and receive IR signals using an ethernet based SBC. This blog describes a small bit of hardware added to the SBC to do this.

IR Firmware for the PIC 18F

Almost every one of my designs involves a periodic timer interrupt. This is used for all timing. For the IR receive, the input may have to be sampled every 25 us. This is a very short interrupt period. For an IR send, the input has to be toggled every 12.5 us. This is just not practical.

It was time to explore some of the features of the PIC 18F that I had long ignored. One was the PWM feature which was used to do the IR send. The other was CCP that was used to do the IR Receive. The hardware used has been described in a previous blog.

Using the Microchip TCP/IP stack on Olimex SBCs

To build a web server application on an Olimex Ethernet SBC, you have to download the Olimex version of the Microchip TCP/IP stack and modify it. To get started with it, as a first step, I got rid of files that I don't need for implementing a web server. The Microchip stack uses a ~ variable embedded in HTML pages to serve your custom information on a web page.