Hi there,
Have someone tried to set the lcd controller driver for MPC823 to use a
monochromatic lcd?
I?m trying to do that, initially with 1bit/pixel mode, but I had some problems.
I?ve created a configuration for my LCD and changed the SCCR to set the clock.
The sync signals are OK for this display now.
The problem is: I tried to set some pixels in the framebuffer but I?ve got no
response in the LCD interface data pins.
Looking at the color map default configurations I think that there isn?t
specific configurations for monochrome operation modes.
I tried to change my color map according to the MPC823 reference manual but
nothing hapenned.
Does anyone have some idea about what could be the problem?
I?m using denx kernel 2.4.4-2001-05-12 and a FADS board.
I?m a newbie at Linux framebuffer programming (and at Linux kernel
programming...) so it?s possible that I?m doing something wrong in my test.
I?m using an extremely simple program to test the LCD controller output (just
fill all fb bits with 0 or 1) as follows.
The data pins are always low, except FD0 that is always high (device
open/close, fb filled with 0/1)
PS: I had some doubts about the MPC823 LCD controller manual. I?m not sure if
each bit (or 2-4.. bit group), representing a pixel, is in a separated word or
not (ex. for 8 pixels in 2 bits/pixel mode are represented in the framebuffer:
1111111111111111 or 0000000000000011, 0000000000000011,....). I?m working with
the "not separated words" hypothesis.
************************************************************
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <sys/mman.h>
#ifndef bool
#define bool unsigned char
#endif
#ifndef FALSE
#define FALSE 0
#endif
#ifndef TRUE
#define TRUE 1
#endif
int fbfd = 0;
struct fb_var_screeninfo vinfo;
struct fb_fix_screeninfo finfo;
long int screensize = 0;
char *fbp = 0;
long int location = 0;
bool open_dev() {
/* Open the file for reading and writing */
fbfd = open("/dev/fb0", O_RDWR);
if (!fbfd) {
printf("Error: cannot open framebuffer device.\n");
return FALSE;
}
printf("The framebuffer device was opened successfully.\n");
return TRUE;
} /* open_dev */
void close_dev() {
munmap(fbp, screensize);
close(fbfd);
} /* close_dev */
bool get_info() {
/* Get fixed screen information */
if (ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo)) {
printf("Error reading fixed information.\n");
return FALSE;
}
/* Get variable screen information */
if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
printf("Error reading variable information.\n");
return FALSE;
}
/* Figure out the size of the screen in bytes */
screensize = (vinfo.xres * vinfo.yres * vinfo.bits_per_pixel) / 8;
return TRUE;
} /* get_info */
bool get_map() {
/* Map the device to memory */
fbp = (char *)mmap(0, screensize, PROT_READ | PROT_WRITE, MAP_SHARED,
fbfd, 0);
if ((int)fbp == -1) {
printf("Error: failed to map framebuffer device to memory.\n");
return FALSE;
}
printf("The framebuffer device was mapped to memory successfully.\n");
printf("fbp: %d\n",(int)fbp);
return TRUE;
} /* get_map */
void fill_map_char(unsigned int size,char value) {
int i;
for (i=0;i<size;i++)
fbp[i] = value;
} /* fill_map_char */
void print_menu() {
printf("MENU:\n");
printf("1-Init\n");
printf("2-Fill 0\n");
printf("3-Fill 1\n");
printf("4-Exit\n");
} /* print_menu */
bool choice_menu() {
char opt;
bool open = FALSE;
scanf("%c",&opt);
switch(opt){
case '1': //init
open_dev();
get_info();
get_map();
break;
case '2': //0
if (open)
fill_map_char(screensize,(char)0x00);
break;
case '3': //1
if (open) {
fill_map_char(screensize,(char)0xFF);
}
break;
case '4': //exit
if (open)
close_dev();
return FALSE;
case '\n' :
default :
break;
}
return TRUE;
} /* choice_menu */
int main()
{
print_menu();
while (choice_menu()) {}
return 0;
}
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