This was very complicated project. Finally I learned how to successfully control display with Hitachi hd61830 controller chip and Arduino.
Display works with negative -13V and normal positive +5V voltages. So first I built necessary power supply. Below is it’s circuit drawing.
There is still some ripple voltage on negative line. Some more filtering is maybe needed (capacitors). Also zener goes very hot. Negative voltage regulator would be better choise for longer use. LM337 for example.
The next thing was to figure out how to control hd61830 controller chip with Arduino. Very helpful source code was found from LCDInfo forum. After that I was able to write my own code. It is below.
/* initialization sequence and cls function taken from lcd_hd61830_lib, cdragos69@yahoo.com http://www.skippari.net/lcd/sekalaista/lcd_hd61830_lib.zip found from http://forum.lcdinfo.com/viewtopic.php?t=451 */ // pin assignment const byte E_PIN = 4; const byte RW_PIN = 3; const byte RS_PIN = 2; const byte DB7_PIN = 12; const byte DB6_PIN = 11; const byte DB5_PIN = 10; const byte DB4_PIN = 9; const byte DB3_PIN = 8; const byte DB2_PIN = 7; const byte DB1_PIN = 6; const byte DB0_PIN = 5; void setup() { // Permanently tied up E pin digitalWrite(E_PIN, HIGH); delay(2000); com(word(0x00, 0x38)); // Display ON, master mode, cursor on/blink, text mode, internal CG-ROM com(word(0x01, 0x75)); // 6x8 font com(word(0x02, 0x27)); // 40 horizontal characters com(word(0x03, 0x7F)); // 1/128 duty cycle (128 lines) com(word(0x04, 0x07)); // 8-lines cursor com(word(0x08, 0x00)); // Display start address low com(word(0x09, 0x00)); // Display start address high com(word(0x0A, 0x00)); // Cursor address low com(word(0x0B, 0x00)); // Cursor address high cls(); com(word(B00001100, B01001000)); //letter H com(word(B00001100, B01100101)); //letter e com(word(B00001100, B01101100)); //letter l com(word(B00001100, B01101100)); //letter l com(word(B00001100, B01101111)); //letter o com(word(B00001100, B00100000)); //space com(word(B00001100, B01110111)); //letter w com(word(B00001100, B01101111)); //letter o com(word(B00001100, B01110010)); //letter r com(word(B00001100, B01101100)); //letter l com(word(B00001100, B01100100)); //letter d } void loop() { // nothing here } void cls() { // clear screen com(word(0x0A, 0x00)); // Cursor address low com(word(0x0B, 0x00)); // Cursor address high for(int i=0;i<320;i++) com(word(0x0C,0)); // reset all text memory com(word(0x0A, 0x00)); // Cursor address low com(word(0x0B, 0x00)); // Cursor address high } void com(word dat) { digitalWrite(LED_BUILTIN, HIGH); // data flow indication on digitalWrite(RW_PIN, LOW); digitalWrite(RS_PIN, HIGH); digitalWrite(DB7_PIN, bitRead(dat, 15)); digitalWrite(DB6_PIN, bitRead(dat, 14)); digitalWrite(DB5_PIN, bitRead(dat, 13)); digitalWrite(DB4_PIN, bitRead(dat, 12)); digitalWrite(DB3_PIN, bitRead(dat, 11)); digitalWrite(DB2_PIN, bitRead(dat, 10)); digitalWrite(DB1_PIN, bitRead(dat, 9)); digitalWrite(DB0_PIN, bitRead(dat, 8)); digitalWrite(RW_PIN, LOW); digitalWrite(RS_PIN, LOW); digitalWrite(DB7_PIN, bitRead(dat, 7)); digitalWrite(DB6_PIN, bitRead(dat, 6)); digitalWrite(DB5_PIN, bitRead(dat, 5)); digitalWrite(DB4_PIN, bitRead(dat, 4)); digitalWrite(DB3_PIN, bitRead(dat, 3)); digitalWrite(DB2_PIN, bitRead(dat, 2)); digitalWrite(DB1_PIN, bitRead(dat, 1)); digitalWrite(DB0_PIN, bitRead(dat, 0)); digitalWrite(LED_BUILTIN, LOW); // data flow indication off //wait for busy flag to go away digitalWrite(E_PIN, HIGH); digitalWrite(RW_PIN, HIGH); digitalWrite(RS_PIN, HIGH); do { delay(10); } while (digitalRead(DB7_PIN) == HIGH); }
Display is on text-mode with internal character ROM. The next challenge is to draw something on screen. There is some more images in the meantime. Contrast trimmer is seen on centre of image and zener is it’s left side.