Initial commit

Add startup code for STM32L031K6, and blink two LEDs, one with CPU,
and one with the LPTIM at 60Hz for the (to-be-implemented) Sharp display.

Makefile

@@ -0,0 +1,131 @@
+# Copyright 2019, Max Regan
+#
+# Permission is hereby granted, free of charge, to any person
+# obtaining a copy of this software and associated documentation files
+# (the "Software"), to deal in the Software without restriction,
+# including without limitation the rights to use, copy, modify, merge,
+# publish, distribute, sublicense, and/or sell copies of the Software,
+# and to permit persons to whom the Software is furnished to do so,
+# subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+#
+# Tools
+#
+
+TOOL_PREFIX ?= arm-none-eabi-
+CC			=  $(TOOL_PREFIX)gcc
+CPP			=  $(TOOL_PREFIX)cpp
+AS			=  $(TOOL_PREFIX)as
+LD			=  $(TOOL_PREFIX)gcc
+OBJCOPY		=  $(TOOL_PREFIX)objcopy
+STM32FLASH	?= stm32flash
+
+#
+# Device Variables
+#
+
+DEVICE_TYPE    ?= stm32l031k6
+DEVICE_FAMILY  =  stm32l031xx
+DEVICE_LINE    =  stm32l0xx
+
+
+#
+# Filenames and paths
+#
+
+C_SOURCES   := $(shell find $(SOURCEDIR) -name '*.c')
+S_SOURCES   := $(shell find $(SOURCEDIR) -name '*.s')
+SPP_SOURCES := $(DEVICE_TYPE).S
+SOURCES     =  $(C_SOURCES) $(S_SOURCES) $(SPP_SOURCES)
+
+C_OBJS   := $(patsubst %.c,%.o,$(C_SOURCES))
+S_OBJS   := $(patsubst %.s,%.o,$(S_SOURCES))
+SPP_OBJS := $(patsubst %.S,%.o,$(SPP_SOURCES))
+OBJS     =  $(C_OBJS) $(S_OBJS) $(SPP_OBJS)
+
+LINKER_SCRIPT ?= $(DEVICE_TYPE).ld
+
+OUTPUT_NAME ?= test
+OUTPUT_BIN  ?= $(OUTPUT_NAME).bin
+OUTPUT_ELF  ?= $(OUTPUT_NAME).elf
+
+#
+# Flags
+#
+
+DEVICE_DEFINE = $(subst XX,xx,$(shell echo $(DEVICE_FAMILY) | tr '[:lower:]' '[:upper:]'))
+
+# C pedantism
+CFLAGS =  -Wall -Wextra -Wpedantic
+# Debug/optimization
+CFLAGS += -Og -g3
+# Architecture
+CFLAGS += -mthumb -mcpu=cortex-m0plus
+CFLAGS += -ffreestanding
+# Defines
+CFLAGS += -D$(DEVICE_DEFINE)
+# Includes
+CFLAGS += -I./lib/stm32/$(DEVICE_LINE)/Include
+CFLAGS += -I./lib/CMSIS/Core/Include
+
+# Startup Definitions
+ASFLAGS += -D__STARTUP_CLEAR_BSS
+ASFLAGS += -D__HEAP_SIZE=0 # No heap- let the linker decide it all
+
+LDFLAGS += -nostdinc -lc -lnosys -Wl,--gc-sections -Wl,--print-memory-usage
+
+#
+# Default Target
+#
+.PHONY: build
+build: $(OUTPUT_BIN)
+
+#
+# Build Logic
+#
+
+%.o: %.c
+	@echo "CC $@"
+	@$(CC) $(CFLAGS) -c $< -o $@
+
+%.o: %.S
+	@echo "AS $@"
+	@$(CC) $(ASFLAGS) -c $< -o $@
+
+$(OUTPUT_BIN): $(OUTPUT_ELF)
+	@echo "OBJCOPY $@"
+	@$(OBJCOPY) -O binary $(OUTPUT_ELF) $(OUTPUT_BIN)
+
+$(OUTPUT_ELF): $(LINKER_SCRIPT) $(OBJS)
+	@echo "LD $@"
+	$(LD) $(LDFLAGS) -T $(LINKER_SCRIPT) -o $(OUTPUT_ELF) $(OBJS)
+
+#
+# Utilities
+#
+
+STM32FLASH_DEVICE = /dev/ttyUSB0
+
+.PHONY: flash
+flash: $(OUTPUT_BIN)
+	@echo "FLASH $(OUTPUT_BIN)"
+	@st-flash write $(OUTPUT_BIN) 0x8000000 2> /dev/null
+#	stm32flash -w $(OUTPUT_BIN) $(STM32FLASH_DEVICE)
+
+
+.PHONY: clean
+clean:
+	@echo "RM $(OBJS)"
+	@rm -f $(OBJS) $(OUTPUT_BIN) $(OUTPUT_ELF)