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attention:
the additional support of direct I/O starting with version 1.92 requested a change in the API:
instead of int filehandles a structure ppd (parallel port descriptor) is now used.
serdisp_init() now has an extra parameter that will be used in the future.
further infos on api-changes: HISTORY
serdisp_parport.h offers some functions for opening and closing a parallel port using a parallel port descriptor ('ppd').ioctl-calls or direct I/O using outp-calls.PP_import().
serdisp_PP_t* PP_open (const char ppdev[])
opens a parport device
ppdev ...device name or port-number of device to open
eg: linux: "/dev/parport0" or "0x378" (for direct IO)
freebsd: "/dev/ppi0"
returns a parallel port descriptor or (serdisp_PP_t*)0 if operation was not successful
void PP_close (serdisp_PP_t* ppd) close the parport device ppd ... parallel port descriptor
serdisp_PP_t* PP_import (int directIO, int hport) import an existing already opened parport device / port and create a ppd struct out of it directIO ... 1: yes -> outp-calls, 0: no -> ioctl-calls hport ... if directIO: port (eg: 0x378), else: descriptor for parport dev returns a parallel port descriptor or (serdisp_PP_t*)0 if operation was not successful USE WITH CARE!!! all permissions and stuff like that must be ok before!! no checking for validity in here
serdisp_t* serdisp_init (serdisp_PP_t* ppd, const char dispname[], const char extra[]) initialises a display. all capabilities and basic values are set ppd ... parallel port descriptor dispname ... display name (for now: "OPTREX323", "PCD8544", "SED1565", "NOKIA7110") extra ... extra settings (will be used in the future. eg. for wiring or other non-standard settings) returns a display descriptorExample:
serdisp_t* dd; dd = serdisp_init(ppd, "PCD8544", "");
void serdisp_close (serdisp_t* dd) close (switch off) display dd ... display descriptor
int serdisp_getwidth (serdisp_t* dd) get width of the display dd ... display descriptor returns the width of the display
int serdisp_getheight (serdisp_t* dd) get height of the display dd ... display descriptor returns the height of the display
int serdisp_getcolours (serdisp_t* dd) get amount of colours supported by the display dd ... display descriptor returns the amount of supported colours
void serdisp_feature (serdisp_t* dd, int feature, int value)
change a display feature
dd ... display descriptor
feature ... feature to change:
FEATURE_CONTRAST .. change display contrast (value: 0-MAX_CONTRASTSTEP)
FEATURE_BACKLIGHT .. 0: off, 1: on, 2: toggle
FEATURE_REVERSE .. 0: normal display, 1: reversed display, 2: toggle
FEATURE_ROTATE .. 0: normal, 1: bottom-up
value ... value for option (see above)
Examples:
serdisp_feature(dd, FEATURE_BACKLIGHT, FEATURE_TOGGLE); serdisp_feature(dd, CONTRAST, 5);
void serdisp_clearbuffer (serdisp_t* dd) resets the internal display-buffer that is used by serdisplib display is NOT redrawn here! dd ... display descriptor
void serdisp_clear (serdisp_t* dd) clear whole display dd ... display descriptor
void serdisp_update (serdisp_t* dd) update whole display dd ... display descriptor
void serdisp_rewrite (serdisp_t* dd) rewrite the whole display dd ... display descriptor
void serdisp_blink (serdisp_t* dd, int what, int cnt, int delta) blink the display dd ... display descriptor what ... 0: blinking using backlight, 1: blinking using display reversing cnt ... how often should there be blinking delta ... delay between two blinking intervals
void serdisp_setpixel (serdisp_t* dd, int x, int y, int colour) changes a pixel in the display buffer dd ... display descriptor x ... x-position y ... y-position colour ... monochrome: 0: clear (white), <>0: set (black); else: up to 16m colours (dependend on display)
void serdisp_setpixels (serdisp_t* dd, int x, int y, int w, int h, byte* data)
changes an area in the display buffer
dd ... display descriptor
x ... x-position top/left
y ... y-position top/left
w ... width of content
h ... height of content
data ... pixel/colour data
(if display supports <= 256 colours:
one byte == one pixel
else:
four byte == one pixel (this may change in the future)
)
Example:
byte* data = .....; /* fill pixel/colour-data into 'data' .... .... /* draw a 5x5 area starting at position 5/10 */ serdisp_setpixels(dd, 5, 10, 5, 5, data);
int serdisp_getpixel (serdisp_t* dd, int x, int y) get colour of pixel at (x/y) dd ... display descriptor x ... x-position y ... y-position
char ppdev[] = "/dev/parport0";
serdisp_PP_t* ppd;
serdisp_t* dd = 0;
int i;
/* opening the parallel port device */
ppd = PP_open(ppdev);
if (ppd == (serdisp_PP_t*)0) {
fprintf(stderr, "Error opening %s\n", ppdev);
exit (1);
}
/* opening and initialising the display */
dd = serdisp_init(ppd, "PCD8544", "");
if (!dd) {
fprintf(stderr, "Error opening display.\nExiting ...\n\n".);
exit(1);
}
/* turning on backlight */
serdisp_feature(dd, FEATURE_BACKLIGHT, FEATURE_YES);
/* clearing the display */
serdisp_clear(dd);
/* draw a border (only internal display buffer is affected!!) */
for (i = 0; i < serdisp_getwidth(dd); i++) {
serdisp_setpixel(dd, i, 0, 1);
serdisp_setpixel(dd, i, serdisp_getheight(dd)-1, 1);
}
for (i = 1; i < serdisp_getheight(dd)-1; i++) {
serdisp_setpixel(dd, 0, i, 1);
serdisp_setpixel(dd, serdisp_getwidth(dd)-1, 1);
}
/* commit changes -> update the display using the internal display buffer */
serdisp_update(dd);
/* some delay */
usleep(100000);
/* close the display */
serdisp_close(dd);
/* release parallel port */
PP_close(ppd);