I am trying to write the code for an embedded board (RX63N)in which I want to use the LCD along with the on board switches for the following functionality: On pressing the switch the program should "pause" or "unpause" depending on the previous state and the LCD should display "paused" when it is paused. On unpausing, the LCD should display the custom graphics at the position defined by x and y. It is displayed using the function Set_LCD_Char(N) where N is defined as a custom graphic from a bitmap image. But I will need to clear the LCD before making any changes and that is where I am struggling. On using lcd_clear() function anywhere in the while keeps the LCD blank (or almost blank i.e. the text and graphics are so faint that they are as good as absent) Can someone please help me? heres the code:
while (1)
{
// lcd_clear();
if(g_sw3_press == true){ //detect switch press
pause_flag = !pause_flag;
g_sw3_press = false; //reset switch
}
if (pause_flag){
RESET_ALL_LEDS();
jet_x = 0;
jet_y = 0;
Set_Font_Bitmap(); //changes from text mode to bitmap
Set_LCD_Pos(jet_x,jet_y);
Set_LCD_Char(3);
}
else if(!(pause_flag)){
ALL_RED_LEDS_ON();
Set_Font_8_by_8();
lcd_display(LCD_LINE1, " PAUSED ");
}
}
1 Answer
Firstly, it's generally not a good idea to do a busy polling loop as you are doing. But I can't recommend any concrete alternatives as platform and OS (if any) have not been provided (perhaps your platform has no support for events).
Anyway, not sure if this is the answer you need. But since you ask for an example and I can't effectively put code into the comments, below is what I mean. The problem is that you are continuously writing and clearing the LCD. So in effect the two operations are competing with each other. So one way to solve this is to only update the LCD when the state changes.
while (1)
{
if(g_sw3_press == true){ //detect switch press
pause_flag = !pause_flag;
g_sw3_press = false; //reset switch
} else {
/* No state change - nothing to do. Poll again. */
continue;
}
lcd_clear();
if (pause_flag){
RESET_ALL_LEDS();
jet_x = 0;
jet_y = 0;
Set_Font_Bitmap(); //changes from text mode to bitmap
Set_LCD_Pos(jet_x,jet_y);
Set_LCD_Char(3);
} else {
ALL_RED_LEDS_ON();
Set_Font_8_by_8();
lcd_display(LCD_LINE1, " PAUSED ");
}
}
