avr

Install

• Download u8glib_avr_vX.XX.zip
• Extract content to a local directory
• Add all files (.c files and u8g.h) of the u8glib/src directory to your project
• Update search path for the include file (if required)
• AVR Studio 4: Set additional options (Project - Configuration - Custom Options)
  • [All Files]
    • -ffunction-sections
    • -fdata-sections
  • [Linker Options]
    • -Wl,--gc-sections
• AVR Studio 6: See M2tklib Instructions for AVR

Setup

Hello World Example

Here is the "Hello World" example:

#include "u8g.h"
#include <avr/interrupt.h>
#include <avr/io.h>

u8g_t u8g;

void draw(void)
{
  u8g_SetFont(&u8g, u8g_font_6x10);
  u8g_DrawStr(&u8g, 0, 15, "Hello World!");
}

int main(void)
{
  /* select minimal prescaler (max system speed) */
  CLKPR = 0x80;
  CLKPR = 0x00;
  /*
    CS: PORTB, Bit 2 --> PN(1,2)
    A0: PORTB, Bit 1 --> PN(1,1)
    SCK: PORTB, Bit 5 --> PN(1,5)
    MOSI: PORTB, Bit 3 --> PN(1,3)
  */
  u8g_InitSPI(&u8g, &u8g_dev_st7565_dogm132_sw_spi, PN(1, 5), PN(1, 3), PN(1, 2), PN(1, 1), U8G_PIN_NONE);

  for(;;)
  {  
    u8g_FirstPage(&u8g);
    do
    {
      draw();
    } while ( u8g_NextPage(&u8g) );
    u8g_Delay(100);
  } 
}

U8glib Init

The example above uses

  u8g_InitSPI(&u8g, &u8g_dev_st7565_dogm132_sw_spi, PN(1, 5), PN(1, 3), PN(1, 2), PN(1, 1), U8G_PIN_NONE);

All devices with _sw_spi or _hw_spi can be used as second argument. Please look at the device wiki page for a list of available devices.

The prototyp for u8g_InitSPI is

uint8_t u8g_InitSPI(u8g_t *u8g, u8g_dev_t *dev, uint8_t sck, uint8_t mosi, uint8_t cs, uint8_t a0, uint8_t reset);

Arguments are:

• u8g: Address of a u8g object
• dev: Address of a display device
• sck: Clock line
• mosi: Data line from controller to display
• cs: Chip select line of the display
• a0: Register select (RS) of the display All pin names must have the form PN(port-numer, bit-position), with:
• port-number: 0 for PORTA, 1, for PORTB, 2 for PORTC, ... and
• bit-position: The position of the pin within a byte.

U8glib Hardware SPI

To use the hardware SPI device simply replace the sw-spi device with the hardware variant:

  u8g_InitSPI(&u8g, &u8g_dev_st7565_dogm132_hw_spi, PN(1, 5), PN(1, 3), PN(1, 2), PN(1, 1), U8G_PIN_NONE);

Notes:

• The atmega hardware SPI communication has been written for the ATMEGA88. It might be required to change some settings in u8g_com_atmega_hw_spi.c for other AVR controller:
• It might be required to set the chip select pin of the AVR SPI subsystem to output. If this pin is not used as cs or a0 for the display, then this pin must be manually set to output.

Links

• Tutorial: Hello World
• List of devices, supported by U8glib
• U8glib Wiki