added PWM example

README.md

@@ -32,3 +32,5 @@ Flash written and verified! jolly good!
 * clock - An example to bump the clock speed to 72 Mhz
 * ext_int - An external interrupt example to toggle LEDs using button presses. Uses EXTI0 and EXTI1 modules.
 * timer - A timer example to toggle LEDs in 1 second intervals. Uses Timer3 module.
+* timer_int - A timer example to toggle LEDs in 1 second intervals. Uses Timer3 module and interrupt.
+* pwm - A PWM example to fade PE14. Uses Timer1 module and interrupt.

pwm/makefile

@@ -0,0 +1,64 @@
+TARGET = pwm
+SRCS = pwm.c
+
+OBJS =  $(addsuffix .o, $(basename $(SRCS)))
+INCLUDES = -I.
+
+LINKER_SCRIPT = stm32.ld
+
+CFLAGS += -mcpu=cortex-m3 -mthumb # Processor setup
+CFLAGS += -O0  # Optimization is off
+CFLAGS += -g3  # Generate debug information
+CFLAGS += -fno-common -Wall
+CFLAGS += -ffunction-sections -fdata-sections -Wl,--gc-sections
+
+LDFLAGS += -nostartfiles -T$(LINKER_SCRIPT)
+
+CROSS_COMPILE = arm-none-eabi-
+CC = $(CROSS_COMPILE)gcc
+LD = $(CROSS_COMPILE)ld
+OBJDUMP = $(CROSS_COMPILE)objdump
+OBJCOPY = $(CROSS_COMPILE)objcopy
+SIZE = $(CROSS_COMPILE)size
+
+all: clean $(SRCS) build size
+	@echo "Successfully finished..."
+
+build: $(TARGET).elf $(TARGET).hex $(TARGET).bin $(TARGET).lst
+
+$(TARGET).elf: $(OBJS)
+	@$(CC) $(LDFLAGS) $(OBJS) -o $@
+
+%.o: %.c
+	@echo "Building" $<
+	@$(CC) $(CFLAGS) $(INCLUDES) -c $< -o $@
+
+%.o: %.s
+	@echo "Building" $<
+	@$(CC) $(CFLAGS) -c $< -o $@
+
+%.hex: %.elf
+	@$(OBJCOPY) -O ihex $< $@
+
+%.bin: %.elf
+	@$(OBJCOPY) -O binary $< $@
+
+%.lst: %.elf
+	@$(OBJDUMP) -x -S $(TARGET).elf > $@
+
+size: $(TARGET).elf
+	@$(SIZE) $(TARGET).elf
+
+burn:
+	@st-flash write $(TARGET).bin 0x8000000
+
+clean:
+	@echo "Cleaning..."
+	@rm -f $(TARGET).elf
+	@rm -f $(TARGET).bin
+	@rm -f $(TARGET).map
+	@rm -f $(TARGET).hex
+	@rm -f $(TARGET).lst
+	@rm -f $(TARGET).o
+
+.PHONY: all build size clean burn