Chumby device settings information on /dev
From Chumby Wiki
/dev/fb
/dev/fb stand for a pointer to the video memory. You writes in it, it draws pixels on the chumby screen.
see the fbwrite project (really easy to read if you know C)
http://files.chumby.com/source/ironforge/build396/fbwrite-1.0.tar.gz
http://files.chumby.com/source/
/dev/accel
http://forum.chumby.com/viewtopic.php?id=759
/dev/ts
Why use /dev/ts ?
- faster
- direct connection with the driver
- I had a problem using /proc/chumby/touchscreen/coordinates without using /bin/cat
How to read /dev/ts in C
see coordinates in /proc page for value explanation (pressure).
#include <stdio.h> #include <unistd.h> #include <sys/stat.h> #include <fcntl.h> #include <signal.h> short *buf; int read_coor() { int fd; int n = 0; if (0 > (fd = open("/dev/ts", O_RDONLY))) { perror("file "); return 0; } buf = (short *)malloc(4 * sizeof(short)); do { if((n = read(fd, buf, 4 * sizeof(short))) < 0) perror("read"); printf("read n[%d] p[%d] x[%d] y[%d] unknown[%d]\n", n, buf[0], buf[1], buf[2], buf[3]); }while(n > 0); free(buf); buf = 0; return close(fd); } void killall(int t) { printf("clean exit\n"); if (buf) free(buf); buf = 0; exit(0); } int main() { signal(SIGINT, killall); read_coor(); return 0; }
example of output
Launch it, click on the screen then, exit with ctrl-c.
read n[8] p[4973] x[1702] y[2489] unknown[671] read n[8] p[4974] x[1697] y[2501] unknown[765] read n[8] p[4973] x[1721] y[2621] unknown[865] read n[8] p[4974] x[1734] y[2825] unknown[966] read n[8] p[0] x[0] y[0] unknown[1212] clean exit