From 875a8291ecf4dc74800b7d8c7cd0dc62b9d582bf Mon Sep 17 00:00:00 2001
From: Matt Mullins <mmullins@mmlx.us>
Date: Sat, 22 Dec 2012 18:57:24 -0800
Subject: [PATCH] Blinks an LED from the reset ISR

---
 Makefile    |  4 ++--
 isr_table.c |  4 +++-
 led_blink.c | 32 ++++++++++++++++++++++++++++++++
 led_blink.h |  6 ++++++
 4 files changed, 43 insertions(+), 3 deletions(-)
 create mode 100644 led_blink.c
 create mode 100644 led_blink.h

diff --git a/Makefile b/Makefile
index c08c72a..251d061 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@ CC=$(ARCH)-gcc
 LD=$(ARCH)-ld
 OBJCOPY=$(ARCH)-objcopy
 
-CFLAGS=-mcpu=cortex-m4 -nostdinc -I $(STELLARISWARE)/inc
+CFLAGS=-ggdb -std=gnu99 -mcpu=cortex-m4 -nostdinc -I $(STELLARISWARE)/inc
 LDFLAGS=-Tstellaris.t
 
 STELLARISWARE=/home/mmullins/projects/stellaris/StellarisWare
@@ -13,7 +13,7 @@ all: led_blink.bin
 %.o: %.c
 	$(CC) $(CFLAGS) -c -o $@ $^
 
-led_blink: isr_table.o
+led_blink: isr_table.o led_blink.o
 	$(LD) $(LDFLAGS) -o $@ $^
 
 led_blink.bin: led_blink
diff --git a/isr_table.c b/isr_table.c
index 198e8f1..e013b40 100644
--- a/isr_table.c
+++ b/isr_table.c
@@ -1,9 +1,11 @@
+#include "led_blink.h"
+
 static void infinite_loop_isr();
 
 __attribute__((section(".reset")))
 void (*reset_vectors[])() = {
 	(void(*)()) 0x20007000,
-	infinite_loop_isr,
+	main_isr,
 	infinite_loop_isr,
 	infinite_loop_isr,
 	infinite_loop_isr,
diff --git a/led_blink.c b/led_blink.c
new file mode 100644
index 0000000..9b0f47b
--- /dev/null
+++ b/led_blink.c
@@ -0,0 +1,32 @@
+#include "led_blink.h"
+#include <lm4f120h5qr.h>
+
+__attribute__((isr))
+void main_isr() {
+	// Enable Port F
+	SYSCTL_RCGCGPIO_R = 0x20;
+
+	// Wait for a few clocks to let GPIO module stabilize
+	for (int i = 0; i < 10; ++i) {
+	}
+
+	// RGB pins (PF1, 2, 3) as outputs
+	GPIO_PORTF_DIR_R = 0xE;
+
+	// deliver 2mA of current
+	GPIO_PORTF_DR2R_R = 0xE;
+
+	// set to digital mode
+	GPIO_PORTF_DEN_R = 0xE;
+
+	// Set RGB pins to 1
+	*(GPIO_PORTF_DATA_BITS_R + 0xE) = 0x2;
+
+	// infinite loop
+	for (;;) { 
+		*(GPIO_PORTF_DATA_BITS_R + 0xC) ^= 0xC;
+
+		for (int j = 0; j < 1000000; ++j) {
+		}
+	}
+}
diff --git a/led_blink.h b/led_blink.h
new file mode 100644
index 0000000..24c4feb
--- /dev/null
+++ b/led_blink.h
@@ -0,0 +1,6 @@
+#ifndef __led_blink_H__
+#define __led_blink_H__
+
+extern void main_isr();
+
+#endif
-- 
2.11.0