* 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!
*
* */
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
+#include <stdarg.h>
#include <sys/mmap.h>
#include <sys/robsys.h>
#include <lib/regfunc.h>
#include <lib/string.h>
#include <lib/tinyprintf.h>
+#include <lib/fonts/wogfont.h>
+#include <drivers/uart.h>
#include <drivers/st7735s.h>
-void tft_command();
+#define TIMEOUT 500
+#define SCRWIDTH 132
+#define SCRHEIGHT 132
+#define STARTX 5
+#define STARTY 5
+#define XPOS(x) (x * 6)
+#define YPOS(y) (y * 8)
+#define BUFFER 352
+
+
+static struct {
+ uint16_t cpos;
+ uint8_t * textmemptr;
+ uint8_t buf[BUFFER];
+ uint8_t x;
+ uint8_t y;
+} tftscreen;
+
void tft_init() {
+ tftscreen.x = 0;
+ tftscreen.y = 0;
+ tftscreen.cpos = 0;
+ tftscreen.textmemptr = tftscreen.buf;
+
+ memset(tftscreen.buf, 0x00, 352);
+
/* Peripherial init */
rsetbit(RCC_APB1ENR, 14); // enable SPI2
rsetbit(RCC_APB2ENR, 3); // enable GPIOB
+ rsetbit(RCC_APB2ENR, 4); // enable GPIOC
- /* The PINS used are respective PB12, PB13 and PB15
+ /* The PINS used are PB12, PB13, PB15 and PC6 respectively
* NSS (or CS): alternative function pusp-pull
* NSS Output is (always high) enabled with this setting
* SCK Master: alternate function push-pull
- * MOSI (or DI): alternate function push-pull */
+ * MOSI (or DI): alternate function push-pull
+ * D/CX (or A0): Command or data write line PC6 */
rwrite(GPIOB_CRH, 0xA4AA4444);
+ rwrite(GPIOC_CRL, 0x42444444);
- /* Chip select: software enabled */
+ /* Chip select: software enabled
+ * In case for a hardware setup, connect NSS (CS) to
+ * ground */
rsetbit(SPI2_CR1, 9);
rsetbit(SPI2_CR1, 8);
- // LOW and first edge: standard settings
-
rsetbit(SPI2_CR1, 15); // one-wire mode
rsetbit(SPI2_CR1, 14); // start with transfer
rsetbit(SPI2_CR1, 4); // FPLCK div 8
rsetbit(SPI2_CR1, 2); // master selection
rsetbit(SPI2_CR1, 6); // enable SPI
- tft_command();
+ /* Init sequence */
+ tft_command(TFT_SWRESET, 0);
+ _block(120000);
+ tft_command(0x11, 0);
+ _block(120000);
+
+ /* Frame rate control */
+ tft_command(TFT_FRMCTR1, 3, 0x01, 0x2C, 0x2D);
+ tft_command(TFT_FRMCTR2, 3, 0x01, 0x2C, 0x2D);
+ tft_command(TFT_FRMCTR3, 6, 0x01, 0x2C, 0x2D, 0x01, 0x2C, 0x2D);
+ /* Power control */
+ tft_command(TFT_PWCTR1, 3, 0xA2, 0x02, 0x84);
+ tft_command(TFT_PWCTR2, 1, 0xC5);
+ tft_command(TFT_PWCTR3, 2, 0x0A, 0x00);
+ tft_command(TFT_PWCTR4, 2, 0x8A, 0x2A);
+ tft_command(TFT_PWCTR5, 2, 0x8A, 0xEE);
+ tft_command(TFT_VMCTR1, 1, 0x0E);
+
+ tft_command(TFT_INVOFF, 0);
+ tft_command(TFT_COLMOD, 1, 0x05); // 0x05
+ tft_command(TFT_MADCTL, 1, 0xC0); // TODO: check
+
+ tft_command(TFT_CASET, 4, 0x00, 0x00, 0x00, 0x7F);
+ tft_command(TFT_RASET, 4, 0x00, 0x00, 0x00, 0x9F);
+
+ /* Gamma Settings */
+ tft_command(TFT_GMCTRP1, 16, 0x02, 0x1C, 0x07, 0x12,
+ 0x37, 0x32, 0x29, 0x2D,
+ 0x29, 0x25, 0x2B, 0x39,
+ 0x00, 0x01, 0x03, 0x10);
+ tft_command(TFT_GMCTRN1, 16, 0x03, 0x1D, 0x07, 0x06,
+ 0x2E, 0x2C, 0x29, 0x2D,
+ 0x2E, 0x2E, 0x37, 0x3F,
+ 0x00, 0x00, 0x02, 0x10);
+
+ /* Before turning on the display, fill the display
+ * so no random display data is shown */
+ tft_fill(0,0,SCRWIDTH-1,SCRHEIGHT-1,0x0000);
+
+ /* Turn on */
+ tft_command(TFT_NORON, 0);
+ _block(10000);
+ tft_command(TFT_DISPON, 0);
+ _block(100000);
+
}
+/* Helper function */
+static int txbuf_empty () {
+ int cnt = 0;
+ while(!rchkbit(SPI2_SR, 1)) {
+ cnt++;
+ if (cnt > TIMEOUT) {
+ printf("Error: transmit timeout!\n");
+ return 0;
+ }
+ }
+ return 1;
-void tft_command() {
+}
- /* 9-bit hack */
- uint8_t cmd = 0x0A;
- rwrite(SPI2_DR, cmd);
- while (!rchkbit(SPI2_SR, 1));
- rclrbit(SPI2_CR1, 14); // receive
+/* Function to fill an area starting at (beginx, beginy)
+ * and end ending at (endx, endy */
+int tft_fill(uint8_t beginx, uint8_t beginy, uint8_t endx,
+ uint8_t endy, uint16_t color) {
+
+ /* The CASET and RASET commands set the begin X/Y
+ * and end X/Y of the fill area. Both are split over
+ * two paramters/bytes. Most screen are small, so you will
+ * only need to consider the first 8 MSBs. Parameter 1 and
+ * 3 are always 0.
+ *
+ * In theory, TFT screens of 65,535 by 65,535 could be
+ * supported */
+ tft_command(TFT_CASET, 4, 0x00, beginx, 0x00, endx);
+ tft_command(TFT_RASET, 4, 0x00, beginy, 0x00, endy);
+
+ /* After setting the fill area, we can send the color
+ * data. The chip autoincrements the address so we can
+ * keep writing continiously for the fill area. Note
+ * that each pixel requires two bytes to be send (16
+ * bit mode: ...) */
+ uint32_t totalwrites = (endx - beginx) * (endy - beginy) * 2;
+ //printf("tw: %d, x: %d, y: %d\n", totalwrites, beginx, beginy);
+ tft_command(TFT_RAMWR, 0);
+ rsetbit(GPIOC_ODR, 6); // data = 1
+ for (int i = 0; i < totalwrites; i++) {
+ rwrite(SPI2_DR, (uint8_t) (color >> 8));
+ if (!txbuf_empty())
+ return -1;
+ rwrite(SPI2_DR, (uint8_t) (color & 0xFF));
+ if (!txbuf_empty())
+ return -1;
+ }
+ return 0;
+}
+
+/* Function to individually set a pixel
+ * Refer to tft_fill, similar calls */
+int tft_setpixel(uint8_t x, uint8_t y, uint16_t color) {
+
+ tft_command(TFT_CASET, 4, 0x00, x, 0x00, x+1);
+ tft_command(TFT_RASET, 4, 0x00, y, 0x00, y+1);
+tft_command(TFT_RAMWR, 2, (uint8_t) (color >> 8), (uint8_t) (color & 0xFF));
+ return 0;
+}
+
+
+/* Basic puts function that loops over a string */
+int tft_puts(char * str) {
+
+ for (int i = 0; i < strlen(str); i++) {
+ tft_putc(0xFFFF, 0x0000, str[i]);
+
+ }
+
+}
+
+/* Used by scroll function to overwrite and clear the last
+ * line on the screen */
+void tft_clrln() {
+
+ tft_puts(" ");
+ tftscreen.buf[BUFFER - 21] = '\0';
+ tftscreen.cpos -= 21;
+ tftscreen.y = 14;
}
+
+/* Text scroll function
+ * Refeed the buffer */
+int tft_scroll() {
+
+ /* Scroll the buffer */
+ memcpy(tftscreen.textmemptr, tftscreen.textmemptr + 21, BUFFER - 21);
+ tftscreen.buf[BUFFER - 21] = '\0';
+
+ tftscreen.x = 0;
+ tftscreen.y = 0;
+ tftscreen.cpos = 0;
+
+ tft_puts(tftscreen.buf); // CHECK: ending
+ tftscreen.y = 14;
+ tftscreen.x = 0;
+ tftscreen.cpos = BUFFER - 21;
+}
+
+/* Fills a line with blank characters, returns to
+ * the next line */
+void tft_nl() {
+
+ uint8_t blanks = 21 - tftscreen.x;
+
+ // filler with blank spaces
+ for (int i = 0; i < blanks; i++) {
+ tft_putc(0xFFFF, 0x0000, ' ');
+ }
+
+}
+
+/* Low-level function to print a character to the display
+ * 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') {
+ if (tftscreen.y == 14) {
+ tft_nl();
+ return 1;
+ }
+ else {
+ tft_nl();
+ //if (tftscreen.y < 15)
+ return 1;
+ }
+ }
+
+ if (tftscreen.y >= 15) {
+ tft_scroll();
+ }
+
+ tft_command(TFT_CASET, 4, 0x00, STARTX + XPOS(tftscreen.x), 0x00, (STARTX + 4) + XPOS(tftscreen.x));
+ tft_command(TFT_RASET, 4, 0x00, STARTY + YPOS(tftscreen.y), 0x00, (STARTY + 6) + YPOS(tftscreen.y));
+
+ tft_command(TFT_RAMWR, 0);
+ rsetbit(GPIOC_ODR, 6); // data = 1
+ for (int i = 0; i < totalpixels; i++) {
+
+ current = ASCII5x7[(c * 5) + column];
+
+ if ((current >> (7 - row)) & 0x1) {
+ rwrite(SPI2_DR, (uint8_t) (fg >> 8));
+ if (!txbuf_empty())
+ return -1;
+ rwrite(SPI2_DR, (uint8_t) (fg & 0xFF));
+ if (!txbuf_empty())
+ return -1;
+ }
+ else {
+ rwrite(SPI2_DR, (uint8_t) (bg >> 8));
+ if (!txbuf_empty())
+ return -1;
+ rwrite(SPI2_DR, (uint8_t) (bg & 0xFF));
+ if (!txbuf_empty())
+ return -1;
+ }
+
+ /* Algoritm dependent on draw mode: top down, left right */
+ column++;
+ if (column > 4) {
+ column = 0;
+ row++;
+ }
+ }
+ tftscreen.buf[tftscreen.cpos] = c;
+ tftscreen.cpos++;
+
+ tftscreen.x++;
+ if (tftscreen.x > 20) {
+ tftscreen.x = 0;
+ tftscreen.y++;
+ }
+
+ return 0;
+}
+
+
+
+/* Invokes commands with a variable list of paramaters. Sending parameters
+ * requires the D/CX line to be high */
+int tft_command(uint8_t cmd, int argsc, ...) {
+
+ va_list ap;
+ // command
+ rclrbit(GPIOC_ODR, 6); // D/CX line low
+ rwrite(SPI2_DR, cmd);
+ if (!txbuf_empty())
+ return -1;
+
+ // parameter or data
+ if (argsc > 0) {
+ va_start(ap, argsc);
+ rsetbit(GPIOC_ODR, 6); // D/CX line high
+ for (int i = 0; i < argsc; i++) {
+ uint8_t p = (uint8_t) va_arg(ap, unsigned int);
+ rwrite(SPI2_DR, p);
+ if (!txbuf_empty())
+ return -1;
+ }
+ va_end(ap);
+ }
+ return 0;
+}
+
projects / cortex-from-scratch / blobdiff