[EDIT] change interrupt 0 to 2 to be able to use led matrices

Microcontrollers/LCDMatrix/main.c

@@ -0,0 +1,149 @@
+/* ---------------------------------------------------------------------------
+** This software is in the public domain, furnished "as is", without technical
+** support, and with no warranty, express or implied, as to its usefulness for
+** any purpose.
+**
+** ledmatrix.c
+**
+** Beschrijving:	Simple HT16K33 Ledmatix demo.
+** Target:			AVR mcu
+** Build:			avr-gcc -std=c99 -Wall -O3 -mmcu=atmega128 -D F_CPU=8000000UL -c ledmatrix.c
+**					avr-gcc -g -mmcu=atmega128 -o ledmatrix.elf ledmatrix.o
+**					avr-objcopy -O ihex ledmatrix.elf ledmatrix.hex 
+**					or type 'make'
+** Author: 			dkroeske@gmail.com
+** -------------------------------------------------------------------------*/
+
+
+#include <avr/io.h>
+#include <util/delay.h>
+
+/******************************************************************/
+void twi_init(void)
+/* 
+short:			Init AVR TWI interface and set bitrate
+inputs:			
+outputs:	
+notes:			TWI clock is set to 100 kHz
+Version :    	DMK, Initial code
+*******************************************************************/
+{
+	TWSR = 0;
+	TWBR = 32;	 // TWI clock set to 100kHz, prescaler = 0
+}
+
+/******************************************************************/
+void twi_start(void)
+/* 
+short:			Generate TWI start condition
+inputs:		
+outputs:	
+notes:			
+Version :    	DMK, Initial code
+*******************************************************************/
+{
+	TWCR = (0x80 | 0x20 | 0x04);
+	while( 0x00 == (TWCR & 0x80) );
+}
+
+/******************************************************************/
+void twi_stop(void)
+/* 
+short:			Generate TWI stop condition
+inputs:		
+outputs:	
+notes:			
+Version :    	DMK, Initial code
+*******************************************************************/
+{
+	TWCR = (0x80 | 0x10 | 0x04);
+}
+
+/******************************************************************/
+void twi_tx(unsigned char data)
+/* 
+short:			transmit 8 bits data
+inputs:		
+outputs:	
+notes:			
+Version :    	DMK, Initial code
+*******************************************************************/
+{
+	TWDR = data;
+	TWCR = (0x80 | 0x04);
+	while( 0 == (TWCR & 0x80) );
+}
+
+/******************************************************************/
+void wait( int ms )
+/* 
+short:			Busy wait number of millisecs
+inputs:			int ms (Number of millisecs to busy wait)
+outputs:	
+notes:			Busy wait, not very accurate. Make sure (external)
+				clock value is set. This is used by _delay_ms inside
+				util/delay.h
+Version :    	DMK, Initial code
+*******************************************************************/
+{
+	for (int i=0; i<ms; i++)
+	{
+		_delay_ms( 1 );		// library function (max 30 ms at 8MHz)
+	}
+}
+
+/******************************************************************/
+int main( void )
+/* 
+short:			main() loop, entry point of executable
+inputs:			
+outputs:	
+notes:			Looping forever, trashing the HT16K33
+Version :    	DMK, Initial code
+*******************************************************************/
+{
+	
+	twi_init();		// Init TWI interface
+
+	// Init HT16K22. Page 32 datasheet
+	twi_start();
+	twi_tx(0xE0);	// Display I2C addres + R/W bit
+	twi_tx(0x21);	// Internal osc on (page 10 HT16K33)
+	twi_stop();
+
+	twi_start();
+	twi_tx(0xE0);	// Display I2C address + R/W bit
+	twi_tx(0xA0);	// HT16K33 pins all output
+	twi_stop();
+
+	twi_start();
+	twi_tx(0xE0);	// Display I2C address + R/W bit
+	twi_tx(0xE3);	// Display Dimming 4/16 duty cycle
+	twi_stop();
+
+	twi_start();
+	twi_tx(0xE0);	// Display I2C address + R/W bit
+	twi_tx(0x81);	// Display OFF - Blink On
+	twi_stop();
+
+	while (1)
+	{
+		twi_start();
+		twi_tx(0xE0);	// Display I2C addres + R/W bit
+		twi_tx(0x00);	// Address
+		twi_tx(0x00);	// data
+		twi_stop();
+
+		wait(500);	
+
+		twi_start();
+		twi_tx(0xE0);	// Display I2C addres + R/W bit
+		twi_tx(0x00);	// Address
+		twi_tx(0x01);	// data
+		twi_stop();	
+
+		wait(500);
+	}
+
+	return 1;
+}