From 99e4226b74acd4286b735b5da275853701dcacf0 Mon Sep 17 00:00:00 2001
From: Michael Gernoth <michael@gernoth.net>
Date: Sun, 22 Aug 2010 16:28:20 +0200
Subject: [PATCH] beginning i2c

---
 bmc/Makefile |  2 +-
 bmc/bmc.c    |  5 +++++
 bmc/i2c.c    | 26 ++++++++++++++++++++++++++
 bmc/i2c.h    |  3 +++
 4 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 bmc/i2c.c
 create mode 100644 bmc/i2c.h

diff --git a/bmc/Makefile b/bmc/Makefile
index 7915e96..8adc53d 100644
--- a/bmc/Makefile
+++ b/bmc/Makefile
@@ -7,7 +7,7 @@ PMCU=m16
 
 all: bmc.bin
 
-bmc: bmc.o usart.o
+bmc: bmc.o usart.o i2c.o
 
 bmc.bin: bmc
 	$(OBJCOPY) -j .text -j .data -O binary $^ $@
diff --git a/bmc/bmc.c b/bmc/bmc.c
index a0387b3..c786032 100644
--- a/bmc/bmc.c
+++ b/bmc/bmc.c
@@ -1,6 +1,8 @@
 #include <avr/io.h>
+#include <avr/interrupt.h>
 #include <stdio.h>
 #include "usart.h"
+#include "i2c.h"
 
 int main(void)
 {
@@ -11,6 +13,9 @@ int main(void)
 	DDRB = 0xff;
 
 	usart_init();
+	i2c_init();
+
+	sei();
 
 	printf("Hallo!\n");
 
diff --git a/bmc/i2c.c b/bmc/i2c.c
new file mode 100644
index 0000000..992d6ce
--- /dev/null
+++ b/bmc/i2c.c
@@ -0,0 +1,26 @@
+#include <util/twi.h>
+#include <avr/interrupt.h>
+#include <stdio.h>
+#include "i2c.h"
+
+#define TWCR_ACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);  
+#define TWCR_NACK TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC);
+#define TWCR_RESET TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|(0<<TWWC);  
+
+void i2c_init()
+{
+	TWAR = BMC_ADDR;
+	TWCR &= ~(1<<TWSTA)|(1<<TWSTO);
+	TWCR|= (1<<TWEA) | (1<<TWEN)|(1<<TWIE); 
+}
+
+ISR (TWI_vect)
+{
+	printf("Interrupt, Status: %02x!\n", TW_STATUS);
+
+	switch (TW_STATUS) {
+		default:
+			TWCR_RESET;
+			break;
+	}
+}
diff --git a/bmc/i2c.h b/bmc/i2c.h
new file mode 100644
index 0000000..d666669
--- /dev/null
+++ b/bmc/i2c.h
@@ -0,0 +1,3 @@
+#define BMC_ADDR 0x24
+
+void i2c_init();
-- 
2.39.2