During spare time I have been playing with graphical LCD. This time I decided to display simple signals that are stored in microcontroller memory. The idea was to read signal values from look-up table and display waveform on Graphical LCD. To make things more interesting I divided LCD screen in to smaller four screens so I could activate them separately and draw signals in them.
Graphical LCD is the same old HQM1286404 with KS0108 controller. I have used Proteus simulator 128×64 graphical LCD(LGM12641BS1R) which is based on KS0108. How to implement and connect LCD there was a blog post (Simulate KS0108 graphical LCD with Proteus simulator
)about it. I am just going to show main program routine.
As I mentioned I have split 128×64 in to four smaller screens like this:
so I get four smaller 32×63 screens where I can put different information. To do this you can think of many ways of implementation. I have chosen simple solution. I have created a simple structure which holds current active window position and size:
//structure of window coordinates
struct window{
uint8_t xmin;
uint8_t ymin;
uint8_t xmax;
uint8_t ymax;
} win;
And I wrote a function which changes the active window.
void setWindow(uint8_t x0, uint8_t y0, uint8_t x1, uint8_t y1)
{
//clear previous window frame
ks0108DrawRect(win.xmin, win.ymin, win.xmax-win.xmin, win.ymax-win.ymin, WHITE);
//set new window position and size
win.xmin=x0;
win.ymin=y0;
win.xmax=x1;
win.ymax=y1;
//draw frame on active window
ks0108DrawRect(win.xmin, win.ymin, win.xmax-win.xmin, win.ymax-win.ymin, BLACK);
}
It just assigns new coordinates of new window. Also it draws a rectangle around active window. When changing window position to new, old rectangle is deleted. So this makes pretty cool effect.
After the window setting is done, it is time to write a signal drawing function that takes values from the pointed look-up table and draws it on the LCD active window. The function is really simple; the only thing you have to take care of is correct proportions: