Creating an IO Assignment Header File

Posted 2012-07-25 in Software

When developing embedded firmware I like to define macros that provide aliases for the IO port registers that I need. The name of each of the macros will correspond to the net name on the schematic to make it easy to check for errors. I put all of these macros into a single header file that I can include, I have sometimes seen these called board support packages. They can sometime be entire libraries that abstract details of the hardware. In my case they are just simple header files as that is all I need for now.

Recently I decided to automate some of the work of creating these files as it can be very time consuming. This is the Awk script I ended up with.

#!/usr/bin/awk -f
{
    if ($0 == "") next;
 
    if ($2 == "PORTA") { port = "A"; }
    if ($2 == "PORTB") { port = "B"; }
    if ($2 == "PORTC") { port = "C"; }
    if ($2 == "PORTD") { port = "D"; }
    if ($2 == "PORTE") { port = "E"; }
    if ($2 == "PORTF") { port = "F"; }
    if ($2 == "PORTG") { port = "G"; }
 
    print "#define " $1 "_PIN " $3;
    print "#define " $1 "_TRIS TRIS" port "bits.TRIS" port $3;
    print "#define " $1 "_LAT LAT" port "bits.LAT" port $3;
    print "#define " $1 "_PORT PORT" port "bits.R" port $3;
    print "";
}

All I need to do is write a space separated file in which each line contains the name I want, the port it is on and the number of the pin that it is attached to. Then this simple script generates the C code. This was for a PIC24F series micro, I have a slightly different script for a project involving a PIC32 which I may post later.

This makes creating BSP header files really easy, especially if you need to modify the pin assignments!