commit 4d6f3bfec992bddbf2603fcf623229163aecccf5
Author: Olaf Rempel <razzor@kopf-tisch.de>
Date:   Sat May 27 15:25:58 2006 +0200

    initial version

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..52f0906
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,71 @@
+PRG            = dmx3chan
+OBJ            = dmx3chan.o
+MCU_TARGET     = at90s2313
+OPTIMIZE       = -Os
+
+DEFS           =
+LIBS           =
+
+# You should not have to change anything below here.
+
+CC             = avr-gcc
+
+# Override is only needed by avr-lib build system.
+
+override CFLAGS        = -g -Wall $(OPTIMIZE) -mmcu=$(MCU_TARGET) $(DEFS)
+override LDFLAGS       = -Wl,-Map,$(PRG).map
+
+OBJCOPY        = avr-objcopy
+OBJDUMP        = avr-objdump
+SIZE           = avr-size
+
+all: $(PRG).elf lst text eeprom
+	$(SIZE) -x -A $(PRG).elf
+
+$(PRG).elf: $(OBJ)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^ $(LIBS)
+
+clean:
+	rm -rf *.o *.lst *.map $(PRG).elf *.hex *.bin *.srec
+
+lst:  $(PRG).lst
+
+%.lst: %.elf
+	$(OBJDUMP) -h -S $< > $@
+
+# Rules for building the .text rom images
+
+text: hex bin srec
+
+hex:  $(PRG).hex
+bin:  $(PRG).bin
+srec: $(PRG).srec
+
+%.hex: %.elf
+	$(OBJCOPY) -j .text -j .data -O ihex $< $@
+
+%.srec: %.elf
+	$(OBJCOPY) -j .text -j .data -O srec $< $@
+
+%.bin: %.elf
+	$(OBJCOPY) -j .text -j .data -O binary $< $@
+
+# Rules for building the .eeprom rom images
+
+eeprom: ehex ebin esrec
+
+ehex:  $(PRG)_eeprom.hex
+ebin:  $(PRG)_eeprom.bin
+esrec: $(PRG)_eeprom.srec
+
+%_eeprom.hex: %.elf
+	$(OBJCOPY) -j .eeprom --change-section-lma .eeprom=0 -O ihex $< $@
+
+%_eeprom.srec: %.elf
+	$(OBJCOPY) -j .eeprom --change-section-lma .eeprom=0 -O srec $< $@
+
+%_eeprom.bin: %.elf
+	$(OBJCOPY) -j .eeprom --change-section-lma .eeprom=0 -O binary $< $@
+
+install: text
+	avrdude -p m16 -c butterfly -b 19200 -U flash:w:$(PRG).srec
diff --git a/dmx8chan.c b/dmx8chan.c
new file mode 100644
index 0000000..3758a10
--- /dev/null
+++ b/dmx8chan.c
@@ -0,0 +1,134 @@
+/***************************************************************************
+ *   Copyright (C) 05/2006 by Olaf Rempel                                  *
+ *   razzor@kopf-tisch.de                                                  *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
+ ***************************************************************************/
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+#define TIMER1_STEP	40
+#define TIMER1_RELOAD	(0xFFFF - (256 * TIMER1_STEP))
+
+// rx variables
+static uint16_t rx_chan;
+static uint16_t my_base;
+
+// channel values
+static uint8_t chan[8] = { 0xFF, 0xC0, 0xB0, 0x80, 0x40, 0x20, 0x10, 0x00 };
+
+// next OCR1 value
+static uint8_t cnt;
+static uint16_t pwm_load;
+
+/*
+ * Timer 1 Overflow (every 10ms)
+ * - reload 10ms
+ * - schedule compare match in 40us
+ */
+ISR(SIG_OVERFLOW1)
+{
+	TCNT1 = TIMER1_RELOAD;
+	OCR1 = (TIMER1_RELOAD + TIMER1_STEP);
+	pwm_load = (TIMER1_RELOAD + (TIMER1_STEP * 2));
+	cnt = 0x00;
+}
+
+/*
+ * Timer 1 Compare Match (every 40us)
+ * - schedule next compare match in 40us
+ */
+ISR(SIG_OUTPUT_COMPARE1A)
+{
+	OCR1 = pwm_load;
+	pwm_load += TIMER1_STEP;
+
+	uint8_t *tmp = chan;
+
+	cnt--;
+
+	if (cnt == 0xFF)
+		PORTB = 0x00;
+
+	if (*tmp++ >= cnt)
+		PORTB |= (1<<PORTB0);
+
+	if (*tmp++ >= cnt)
+		PORTB |= (1<<PORTB1);
+
+	if (*tmp++ >= cnt)
+		PORTB |= (1<<PORTB2);
+
+	if (*tmp++ >= cnt)
+		PORTB |= (1<<PORTB3);
+
+	if (*tmp++ >= cnt)
+		PORTB |= (1<<PORTB4);
+
+	if (*tmp++ >= cnt)
+		PORTB |= (1<<PORTB5);
+
+	if (*tmp++ >= cnt)
+		PORTB |= (1<<PORTB6);
+
+	if (*tmp++ >= cnt)
+		PORTB |= (1<<PORTB7);
+}
+
+/*
+ * DMX Receive (every 44us)
+ * - count received bytes
+ */
+ISR(SIG_UART_RECV)
+{
+	// FrameError & Data 0x00 -> Reset
+	if (USR & (1<<FE)) {
+		if (UDR == 0)
+			rx_chan = 0;
+
+	// Our 8 channels?
+	} else if ((rx_chan & 0x1F8) == my_base) {
+		chan[(rx_chan++ & 0x07)] = UDR;
+
+	} else {
+		uint8_t tmp = UDR;
+	}
+}
+
+int main(void)
+{
+	/* PortB as outputs */
+	DDRB = 0xFF;
+	PORTB = 0x00;
+
+	/* Uart-Init: 250kBaud, 8n2, receive only */
+	UBRR = 0x01;
+	UCR = (1<<RXCIE) | (1<<RXEN) | (1<<CHR9);
+
+	/* Timer Init: F_OSC/8, overflow & compare Int */
+	TCCR1A = 0x00;
+	TCCR1B = (1<<CS11);
+	TIMSK = (1<<TOIE1) | (1<<OCIE1A);
+	TCNT1 = TIMER1_RELOAD;
+
+	/* Enable Interrupts */
+	sei();
+
+	while (1);
+
+	return 0;
+}