avrlcd.c contains code to use a standard 14-pin LCD based on the
HD44780 with AVR MCUs.  Compile and program using an STK500 with

make program_avrlcd


Line 9 of Makefile is  MCU=at90s8515  and sets the target MCU

Line 12 of Makefile is  PORT=/dev/ttyS0  and sets the output port
that the STK500 connects to.



avrlcd.c has only a few lines you need to be concerned with:

- wiring is defined on lines 25-38

- Line 53 is  #define AVR_FREQ 368000  and defines the AVR clock
rate which is important for proper timing.

- Lines 77-81 are
	#define LCD_DATA_DDR DDRA
	#define LCD_DATA PORTA
	#define LCD_DATA_IN PINA
	#define LCD_CTRL_DDR DDRB
	#define LCD_CTRL PORTB
and define the output ports.  

- main() contains the most basic of usage examples


NOTE: This code takes up a couple KB of your AVR Flash.  The GNU
AVR Toolchain does not do bounds checking when you program a MCU.
If you ever get improper output on your LCD, you either have an
incorrectly defined AVR_FREQ, at some point you write to the LCD's
data and/or control lines with your code, or your program plus the
LCD code take up more flash than the AVR has.  This is a real
possibility if you use any math functions (e.g., pow(x, y) takes
up about 5 KB of space)