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1602 Display Library for AVR

Usage

  • add corresponding files (display1602.c, display1602.h) to your project (if you will add it using some packaging instrument please send me a note about, I'll be glad to add this to documentation
  • consider the build requirements, and check id F_CPU is set, as library utilizes busy-wait delay_ms and delay_ns functions.
  • check wiring. Command and data should use different ports.
    • in display1602.h set CONTROL_1602_PORT CONTROL_1602_PORT_DDR to corresponding PORTX and DDRX. By default it is set to PORTC and DDRC respectively
    • in display1602.h set CONTROL_1602_RS, CONTROL_1602_E, CONTROL_1602_RW to corresponding pins. By default these are set to PC0, PC1 and PC2 respectively.
    • in display1602.h set DATA_1602_PORT and DATA_1602_PORT_DDR to corresponding PORTY and DDRY. By default it is set to PORTD and DDRD respectively.
  • call init_display() on boot.

Examples

Example wiring for atmega8

atmega8 wiring

Initialize and write some text

void init() {
  init_1602_pins();
  init_display();
  write_some_text();
}

void write_some_text() {
  select_1602_line(CMD_1602_DDRAM_LINE1);
  write_1602_line(16,"Looks like it...");
  select_1602_line(CMD_1602_DDRAM_LINE2);
  write_1602_line(9, "works now");
}

Write some text at certain position at line

  select_1602_line(CMD_1602_DDRAM_LINE1);
  write_1602_line(16,"Let it blink!   ");


  for(;;) {
  
    _delay_ms(500);
    //add 7 symbols offset

    select_1602_line(CMD_1602_DDRAM_LINE1 + 7);
    write_1602_line(5,"poops");

    //repeat last action
    _delay_ms(500);
    //add 7 symbols offset

    select_1602_line(CMD_1602_DDRAM_LINE1 + 7);
    write_1602_line(5,"blink");
}

Limitations:

For now:

  • 4 bit transfer mode is not implemented at the moment (also 74hc595 support is planned, but neither will be implemented until someone will ask me, or I will need it)

  • Display write is totaly sinchronous and takes not less than several milliseconds

  • You cannot divide data pins to several ports (by design)

  • You cannod divide command pins to several ports (design)

  • When I'll get strong vision on timing, maybe I'll add some async nature, with rtos-like x_delays. However, if the current code is suitable for attiny2313, maintaining tasks return points can render unbearable.