Building the drivers

In order to make drivers in rtlinux there is a nice library, called COMEDI, with a lot of cards supported. But here, it has been programmed the driver without using COMEDI library. The reason was that it wasn't needed all the functionality of a driver and there was the source code of the two cards from others operating systems. So, we only need an automatically way of porting it to rtlinux.

• 812: This is a very known and easy A/D converter. I just need some function to write voltages to the robot's motors. So the source code looks like this:

  #include "./pcl812.h"
  #include <asm/io.h>
  
  int pcl_read_polled(
          int channel, 
          unsigned char *higher,
          unsigned char *lower
          )
  {
     if ( channel < 16)
      {
        /* Read analog input */
        // Select input channel.  
        outb(channel,BASE+10); 
        /* Start an ADC conversion 
        and wait for ready */
        /* Any value causes trigger */
        outb(5,BASE+12); 
        /* Wait until data is ready */
        while((inb(BASE+5)&0x10) != 0)
             {};
  
        if((*higher=(inb(BASE+5)))>=16)
          /* Nothing readen */
           return (-EINVAL); 
   
        *lower=inb(BASE+4);
       }
    else if (channel==18)
      {
        /* read LSB */
        *lower=inb(BASE+6);
        /* and add the MSB */ 
        *higher=inb(BASE+7);     
      }
    else return(-ENODEV);
   
    return 0;
   
  }
  

• 833: The DOS source code for this driver is supplied by the manufacturer. So, it is only needed to port it to rtlinux. This can be done easily by adding this lines:

  //used to adapt the driver code to LINUX.
  #define  outportb(a,b) outb(b,a)
  #define  inportb(a)    inb(a)
  

• jr3:The DOS/Windows NT source code for this driver was found so we adapt it by adding the same lines and removing some O.S. specific operating system calls.

  //used to adapt the driver code to LINUX.
  #define outpw(a,b) outw(b,a)
  #define inpw(a) inw(a)
  #include <asm/io.h>