Matt Lesslaw
Derived work demoing the Crystalfontz CHARACTER LCD MODULE
Diff: main.cpp
- Revision:
- 0:a6f66204f651
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Mon Jul 09 22:59:06 2012 +0000
@@ -0,0 +1,318 @@
+/*
+
+ Derived from http://mbed.org/users/JohnSchooling/programs/pwm_trinary_count_01/m9rhax
+
+
+ * mbed demo:
+ * Software PWM on the mbed LEDs. Counting in trinary using off, half bright and full on LEDs.
+ * Smooth scrolling a graphic on a 16x2 LCD display (using ST7066U controller).
+ *
+ * 2012-05-09 John Schooling
+ *
+
+ In order to try and understand what's going on and to customise it later
+ I changed the code into an ST7066U class
+
+
+
+ */
+
+#include "mbed.h"
+
+
+class ST7066U {
+
+ private :
+ DigitalOut *rs, *rw, *e, *db0, *db1, *db2, *db3, *db4, *db5, *db6, *db7;
+ uint8_t lines_bit, font_bit;
+
+ public :
+ ST7066U () {
+ rs = new DigitalOut(p5);
+ rw = new DigitalOut(p6);
+ e = new DigitalOut(p7);
+ db0 = new DigitalOut(p8);
+ db1 = new DigitalOut(p9);
+ db2 = new DigitalOut(p10);
+ db3 = new DigitalOut(p11);
+ db4 = new DigitalOut(p12);
+ db5 = new DigitalOut(p13);
+ db6 = new DigitalOut(p14);
+ db7 = new DigitalOut(p15);
+
+ font_bit = 0;
+ lines_bit = 0;
+
+ wait(0.040); // LCD initialisation takes 40ms.
+ }
+
+ void rows(int l) {
+ if(l == 1)
+ lines_bit = 0;
+ else if (l == 2)
+ lines_bit = 8;
+
+ instruction(32 | 16 | lines_bit | font_bit);
+ }
+
+ void font(int f) {
+ if(f == 0)
+ font_bit = 0;
+ else if (f == 1)
+ font_bit = 4;
+
+ instruction(32 | 16 | lines_bit | font_bit);
+ }
+
+
+ void write(int c, int nrs) {
+ int old_rs = rs->read();
+ // Should check Busy Flag here.
+ rs->write(nrs);
+ e->write(1); // E must be on for min 480ns then drop to zero. Trigger is on falling signal.
+ db0->write(c & 1);
+ db1->write(c>>1 & 1);
+ db2->write(c>>2 & 1);
+ db3->write(c>>3 & 1);
+ db4->write(c>>4 & 1);
+ db5->write(c>>5 & 1);
+ db6->write(c>>6 & 1);
+ db7->write(c>>7 & 1);
+
+ // added extra wait state
+ wait(0.000001); // Needed the equivalent of this on the Raspberry Pi.
+
+ // Tdsw Data Setup Width time at least 80ns. No need for delay on slow processor.
+ e->write(0); // = 0; // Strobe.
+ // Th Data Hold time at least 10ns. No need for delay on slow processor.
+ wait(0.000037); // Most instructions take 37us. May not need this delay if Busy Flag checked at top.
+ rs->write(old_rs);
+ }
+
+ void data(uint8_t c) {
+ write(c, 1);
+ }
+ void instruction(uint8_t c) {
+ write(c, 0);
+ }
+
+ void clear(void) {
+ instruction(1);
+ wait(0.00152); // clear takes 1.52 ms.
+ }
+ void home(void) {
+ instruction(2);
+ wait(0.00152); // home takes 1.52 ms.
+ }
+
+ void str_at(const char *str, uint8_t x = 0, uint8_t y = 0) {
+ uint8_t *c = (uint8_t *) str;
+ ddram(y * 0x40 + x);
+ for (uint8_t i = 0; i < 80 && (*c); i++) { // Will never write more than 80 chars.
+ data(*c);
+ c++;
+ }
+ }
+
+ void row0(const char *str, uint8_t x = 0) {
+ str_at(str, x, 0);
+ }
+
+ void row1(const char *str, uint8_t x = 0) {
+ str_at(str, x, 1);
+ }
+
+ void str(const char *str) {
+ str_at(str);
+ }
+
+ void on() {
+ instruction(0x0C); // 0000 1DCB Display=1 Cursor=0 Blink=0
+
+ }
+
+ void off() {
+ instruction(0x08); // 0000 1DCB Display=0 Cursor=0 Blink=0
+ }
+
+ void cgram(uint8_t a) {
+ instruction(0x40 | a);
+ }
+
+ void ddram(uint8_t a) {
+ instruction(0x80 | a);
+ }
+
+};
+/*
+ Crystalfontz CFAH1602BTMIJT 16x2 LCD display.
+ http://www.coolcomponents.co.uk/catalog/blue-16x2-display-p-151.html (also part of mbed starter kit).
+
+ Sitronix ST7066U functions (compatible with Hitachi HD44780).
+ CFAH1602BTMIJT_v1.0.pdf
+ http://www.crystalfontz.com/controllers/ST7066U.pdf
+
+ LCD initialisation takes 40ms.
+
+ Instruction RS RW 7 6 5 4 3 2 1 0 Time (270kHz)
+ Clear Display 0 0 0 0 0 0 0 0 0 1 1.52 ms Clear, Home, Entry Mode = Increment.
+ Return Home 0 0 0 0 0 0 0 0 1 x 1.52 ms.
+ Entry Mode Set 0 0 0 0 0 0 0 1 I S .037ms Increment cursor, Shift display (shift cursor).
+ Display On/Off 0 0 0 0 0 0 1 D C P .037ms Display on, Cursor on, Position on.
+ Cursor or Display Shift 0 0 0 0 0 1 D R x x .037ms Display shift (cursor shift), Right (left).
+ Function Set 0 0 0 0 1 D N F x x .037ms Data interface 8 (4) bits, Number of lines 2 (1), Font 5x11 if 1 line (5x8).
+ Set CGRAM address 0 0 0 1 A A A A A A .037ms Set 6 bit CGRAM address in address counter.
+ Set DDRAM address 0 0 1 A A A A A A A .037ms Set 7 bit DDRAM address in address counter.
+ Read Busy Flag and addr 0 1 F A A A A A A A .000ms Read Busy Flag and address counter.
+ Write data to RAM 1 0 A A A A A A A A .037ms Write data to RAM (DDRAM or CGRAM). Must do Set address first.
+ Read data from RAM 1 1 A A A A A A A A .037ms Read data from internal RAM (DDRAM or CGRAM). Must do Set address first.
+*/
+
+int face1[8][8] = {
+ {0x01, 0x02, 0x04, 0x08, 0x13, 0x14, 0x14, 0x13} // Top left.
+ , {0x1F, 0x00, 0x00, 0x00, 0x00, 0x11, 0x11, 0x04}
+ , {0x10, 0x08, 0x04, 0x02, 0x19, 0x05, 0x05, 0x19}
+ , {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00} // Top right.
+
+ , {0x10, 0x10, 0x12, 0x11, 0x09, 0x04, 0x02, 0x01} // Bottom left.
+ , {0x04, 0x00, 0x00, 0x00, 0x1F, 0x1F, 0x00, 0x1F}
+ , {0x01, 0x01, 0x09, 0x11, 0x12, 0x04, 0x08, 0x10}
+ , {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00} // Bottom right.
+};
+int face2[8][8] = {
+ {0x01, 0x06, 0x0C, 0x18, 0x30, 0x33, 0x36, 0x36} // Top left.
+ , {0x3F, 0x00, 0x00, 0x00, 0x00, 0x21, 0x33, 0x33}
+ , {0x20, 0x18, 0x0C, 0x06, 0x03, 0x33, 0x1B, 0x1B}
+ , {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00} // Top right.
+
+ , {0x33, 0x30, 0x33, 0x1B, 0x19, 0x0C, 0x06, 0x01} // Bottom left.
+ , {0x21, 0x00, 0x00, 0x00, 0x21, 0x3F, 0x00, 0x3F}
+ , {0x33, 0x03, 0x33, 0x36, 0x26, 0x0C, 0x18, 0x20}
+ , {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00} // Bottom right.
+};
+
+
+
+DigitalOut myled1(LED1);
+DigitalOut myled2(LED2);
+DigitalOut myled3(LED3);
+DigitalOut myled4(LED4);
+
+void scroll_face(ST7066U *lcd) {
+ int pict[8][8];
+ memcpy(pict, face2, sizeof(pict));
+ lcd->cgram(0);
+ for (int i = 0; i < 64; i++) {
+ lcd->data((uint8_t)pict[i/8][i%8]);
+ }
+ // Display the graphic characters.
+ lcd->ddram(0);
+ lcd->data(3); // Top right of graphic.
+ lcd->ddram(64);
+ lcd->data(7); // Bottom right of graphic.
+
+ for (int n = 0; n < 19; n++) {
+ for (int k = 0; k < 6; k++) { // 6 bit Smooth scrolling avoiding jump between characters on display.
+ lcd->cgram(0);
+ for (int i = 63; i >= 0; i--) {
+ if (i/8 == 0 || i/8 == 4) {
+ pict[i/8][i%8] |= ((pict[i/8 +3][i%8] &1) << 6); // Put right hand low bit into bit 6.
+ } else {
+ pict[i/8][i%8] |= ((pict[i/8 -1][i%8] &1) << 6); // Put previous low bit into bit 6.
+ }
+ }
+ for (int i = 0; i < 64; i++) {
+ pict[i/8][i%8] >>= 1; // Scroll the character.
+ lcd->data((uint8_t)pict[i/8][i%8]); // Write to LCD.
+ }
+ wait(0.1);
+ }
+ if(n >= 3) {
+ // Graphic has moved on a whole character. Replace left characters with a space.
+ lcd->ddram(n - 3);
+ lcd->data(' ');
+ lcd->ddram(64 + n - 3);
+ lcd->data(' ');
+ }
+ // Set right side of graphic to correct characters.
+ lcd->ddram(1 + n);
+ lcd->data(n%4);
+ lcd->ddram(64 + 1 + n);
+ lcd->data(n%4 + 4);
+ }
+}
+
+void scroll_bar(ST7066U *lcd) {
+
+ // Scrolling vertical bar to clear the screen.
+ // Bar is two lines (smoother scrolling and more visible than a single line).
+ // There are six combinations for each of the available five bits. Avoids jump between characters on display.
+ // Character number 7 is used for the graphic (0-5 are used by the face). Earlier version left face on screen.
+ for (int i = 0; i < 6 * 17; i++) { // 6 positions for each of 17 characters.
+ lcd->cgram(7 * 8);
+ for (int j = 0; j < 8; j++) {
+ lcd->data((3 << (5 - i%6)) >> 1); // Fill 8 bytes for vertical bar character in Character Generator RAM.
+ }
+ lcd->ddram(i / 6 - (i >= 6));
+ if (i >= 6) lcd->data(0x20);
+ lcd->data(7); // Top row.
+ lcd->ddram(64 + i / 6 - (i >= 6));
+ if (i >= 6) lcd->data(0x20);
+ lcd->data(7); // Bottom row.
+ wait(0.075);
+ }
+}
+
+int main() {
+
+ uint32_t a = 0; // Main PWM loop counter.
+ uint16_t b;
+ int16_t i;
+ uint16_t e4[] = {0, 20, 256}; // LED brightness.
+ char str[17]; // String for writing to the LCD display.
+
+ ST7066U *lcd = new ST7066U();
+
+ lcd->clear();
+ lcd->rows(2);
+ lcd->on();
+
+ lcd->row0("Bedtime", 4);
+ lcd->row1("Counter", 4);
+
+ // Flash display off/on a couple of times.
+ for (int i = 0; i < 2; i++) {
+ wait(0.5);
+ lcd->off(); // 0000 1DCB Display=0 Cursor=0 Blink=0
+ wait(0.5);
+ lcd->on(); // 0000 1DCB Display=1 Cursor=0 Blink=0
+ }
+
+ wait(1);
+ scroll_face(lcd);
+ //scroll_bar();
+
+ // Trinary counting.
+ // Use the mbed LEDs to display trinary values (using software PWM) to count from zero to 80 (trinary 2222).
+ // LED brightness: off = 0, half bright = 1, full on = 2.
+ i = 80; // Force next display value to be zero: (80 + 1) % 81.
+ while (1) {
+ if (a == 0) {
+ // Counter expired: display the next value.
+ i = (i + 1) % 81;
+ // Write decimal and trinary.
+ sprintf(str, "dec %2d tri %d%d%d%d", i, (i / 27) % 3, (i / 9) % 3, (i / 3) % 3, i % 3);
+ lcd->row0(str);
+ // Write hex and binary.
+ sprintf(str, "0x%2.2X 0b0%d%d%d%d%d%d%d", i, i>>6&1, i>>5&1, i>>4&1, i>>3&1, i>>2&1, i>>1&1, i&1);
+ lcd->row1(str);
+ }
+ b = a & 0xFF;
+ // PWM for mbed LEDs. e4 contains the brightness for trit values 0, 1 and 2.
+ myled4 = b < e4[ i % 3] ? 1 : 0;
+ myled3 = b < e4[(i / 3) % 3] ? 1 : 0;
+ myled2 = b < e4[(i / 9) % 3] ? 1 : 0;
+ myled1 = b < e4[(i / 27) % 3] ? 1 : 0;
+ a = (a + 1) & 0x7FFFF; // Loop counter.
+ }
+}