st7735s: documentation, ready for merge

[cortex-from-scratch] / drivers / st7735s.c

diff --git a/drivers/st7735s.c b/drivers/st7735s.c
index c99156f..a3c7117 100644 (file)
--- a/drivers/st7735s.c
+++ b/drivers/st7735s.c
@@ -5,8 +5,19 @@
  * Initial version 
  * 
  * $DESCRIPTION$
+ * Basic driver for the ST7735s TFT screen. Initializes the screen 
+ * Low-level commands can be called by tft_command. See header (.h)
+ * file for an overview of all commands. tft_command can accepts
+ * an unlimited amount of data or parameter commands.
  * 
  * $USAGE$
+ * I added the following functionality:
+ * a. tft_fill: fills a certain area of the screen
+ * b. tft_setpixel: sets a single pixel
+ * c. tft_putc, tft_put: outputs a char/string to the screen, starts
+ * at the upper top right and tracks the position. If the screen is
+ * full, it 'scrolls' automatically. So you basically have a mini 
+ * sized terminal. You can link standard output to this function!
  *
  * */
 
@@ -35,6 +46,7 @@
 #define YPOS(y) (y * 8)
 #define BUFFER 352
 
+
 static struct {
         uint16_t cpos;
         uint8_t * textmemptr;
@@ -188,6 +200,7 @@ tft_command(TFT_RAMWR, 2, (uint8_t) (color >> 8), (uint8_t) (color & 0xFF));
 }
 
 
+/* Basic puts function that loops over a string */
 int tft_puts(char * str) {
 
        for (int i = 0; i < strlen(str); i++)  {
@@ -197,6 +210,8 @@ int tft_puts(char * str) {
        
 }
 
+/* Used by scroll function to overwrite and clear the last
+ * line on the screen */
 void tft_clrln() {
 
        tft_puts("                     ");
@@ -211,26 +226,20 @@ int tft_scroll() {
 
        /* Scroll the buffer  */
        memcpy(tftscreen.textmemptr, tftscreen.textmemptr + 21, BUFFER - 21);
-       //for (int i = 21; i >= 0; i--)
        tftscreen.buf[BUFFER - 21] = '\0';
 
        tftscreen.x = 0;
        tftscreen.y = 0;
        tftscreen.cpos = 0;
 
-       //for (int i = 0; i < 320; i++)     {
-       //      uart_putc(tftscreen.buf[i]);
-       //}
-
        tft_puts(tftscreen.buf); // CHECK: ending
-       //tftscreen.y = 14;
-       //tft_puts("                     ");
        tftscreen.y = 14;
        tftscreen.x = 0;
        tftscreen.cpos = BUFFER - 21;
-       // DINOSAUR tft_clrln();
 }
 
+/* Fills a line with blank characters, returns to 
+ * the next line */
 void tft_nl() {
 
        uint8_t blanks = 21 - tftscreen.x;
@@ -246,19 +255,11 @@ void tft_nl() {
  * Should not be used directly */
 int tft_putc(uint16_t fg, uint16_t bg, int c) {
 
-       
        int totalpixels = 35;
        int column = 0;
        int row = 0;
        uint8_t current;
 
-
-       //if ((c == '\n') && (tftscreen.y == 14)) {
-       //      tft_nl();
-       //      tft_scroll2();
-       //      return 1;
-       //}
-
        if (c == '\n') {
                if (tftscreen.y == 14) {
                        tft_nl();
@@ -270,20 +271,9 @@ int tft_putc(uint16_t fg, uint16_t bg, int c) {
                        return 1;
                }
        }
-       ////    else {
-       ////            tft_putc(0xFFFF, 0x0000, 'o');
-       ////    }
-       //      //else {
-       //      //      ENDFLAG = true;
-       //      //}
-       //}
 
        if (tftscreen.y >= 15) {
                tft_scroll();
-               //if (ENDFLAG) {
-               //      ENDFLAG = false;
-               //      return 1;
-               //}
        }
 
        tft_command(TFT_CASET, 4, 0x00, STARTX + XPOS(tftscreen.x), 0x00, (STARTX + 4) + XPOS(tftscreen.x));