[foxboard] rssreader.c

[Dave Van den Eynde]

Hello,

This week I accomplished something; I managed to hook up a HD47780 style LCD to 
the Fox Board. I did however notice that the program rssreader was using up all 
of the CPU because of its brutal 'delay' routines, so I went looking for a fix 
for this.

I needed a function that would put the process to sleep for at least a given 
period of time and give up the CPU to play nice with other processes. I doesn't 
matter if that time is too long, the whole communication is synchronous anyway. 
I found some documentation on sleep(), nanosleep() and finally settled on using 
the select() function as the documentation that I found stated that it was the 
most portable way of doing it.

I replaced the functions msDelay() and usDelay() with the following:

void msDelay(int ms)
{
  struct timeval tv;

  tv.tv_sec = 0;
  tv.tv_usec = ms * 1000;

  select(0, NULL, NULL, NULL, &tv);
}

void usDelay(int us)
{
  struct timeval tv;

  tv.tv_sec = 0;
  tv.tv_usec = us;

  select(0, NULL, NULL, NULL, &tv);
}

I compiled and ran it for a while and found out system load dropped from >1 to 
0.03. Perhaps this snippet of code is worthy of inclusion in the next version 
of the Fox SDK?

Sincerely,

Dave Van den Eynde