cleanup Readme and generate SBOM

CMakeLists.txt

@@ -1,37 +1,79 @@
 cmake_minimum_required(VERSION 3.13)
-
-# Project
 project(lezyne-rear-light-firmware C)
 
 # MCU and clock
 set(MCU attiny202)
-set(F_CPU 5000000UL) # 5 MHz
+set(F_CPU 5000000UL)
 
-# Toolchain executables
+# Toolchain
 set(CMAKE_SYSTEM_NAME Generic)
 set(CMAKE_C_COMPILER avr-gcc)
 set(OBJCOPY avr-objcopy)
 
-# Compiler flags: optimize, warnings, treat warnings as errors
-set(CMAKE_C_FLAGS "-mmcu=${MCU} -DF_CPU=${F_CPU} -Os -Wall -Werror")
-
 # Sources
 add_executable(main.elf main.c)
 
-# HEX file
-add_custom_command(
-    OUTPUT main.hex
+# Compiler and linker flags
+target_compile_options(main.elf PRIVATE -mmcu=${MCU} -DF_CPU=${F_CPU} -Os -Wall -Werror)
+set_target_properties(main.elf PROPERTIES LINK_FLAGS "-mmcu=${MCU}")
+
+# Create HEX and BIN after build
+add_custom_command(TARGET main.elf POST_BUILD
     COMMAND ${OBJCOPY} -O ihex -R .eeprom main.elf main.hex
-    DEPENDS main.elf
-)
-
-# BIN file
-add_custom_command(
-    OUTPUT main.bin
     COMMAND ${OBJCOPY} -O binary -R .eeprom main.elf main.bin
-    DEPENDS main.elf
 )
 
-# Targets
-add_custom_target(hex ALL DEPENDS main.hex)
-add_custom_target(bin ALL DEPENDS main.bin)
+# Optional: show size
+find_program(SIZE_TOOL avr-size)
+if(SIZE_TOOL)
+    add_custom_command(TARGET main.elf POST_BUILD
+        COMMAND ${SIZE_TOOL} --mcu=${MCU} --format=avr main.elf
+    )
+endif()
+
+# Flash target using pymcuprog
+find_program(PYMCUPROG pymcuprog)
+set(UPDI_PORT "/dev/ttyUSB0" CACHE STRING "Serial port for UPDI programming")
+
+if(PYMCUPROG)
+    add_custom_target(flash
+        COMMAND ${PYMCUPROG} -t uart -u ${UPDI_PORT} -d ${MCU} write -f main.hex
+        DEPENDS main.hex
+        COMMENT "Flashing ${MCU} with pymcuprog..."
+    )
+else()
+    message(WARNING "pymcuprog not found in PATH. 'make flash' will not be available.")
+endif()
+
+# --- SBOM Generation (SPDX JSON) ---
+find_package(Git REQUIRED)
+
+# Generate current timestamp in ISO 8601 format (UTC)
+string(TIMESTAMP CMAKE_TIMESTAMP "%Y-%m-%dT%H:%M:%SZ" UTC)
+
+# Get current git hash
+execute_process(
+    COMMAND ${GIT_EXECUTABLE} rev-parse HEAD
+    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+    OUTPUT_VARIABLE GIT_HASH
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+)
+
+# Get avr-gcc version
+execute_process(
+    COMMAND ${CMAKE_C_COMPILER} --version
+    OUTPUT_VARIABLE AVR_GCC_VERSION
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+)
+
+# Where to write SBOM
+set(SBOM_FILE ${CMAKE_SOURCE_DIR}/sbom.spdx.json)
+
+# Generate from template
+configure_file(${CMAKE_SOURCE_DIR}/sbom.template.json ${SBOM_FILE} @ONLY)
+
+# Always regenerate on build
+add_custom_target(sbom ALL
+    DEPENDS ${SBOM_FILE}
+    COMMENT "Generating SPDX SBOM..."
+)