cmake_minimum_required(VERSION 3.26)

project(avr_blink VERSION 0.1.0.0 LANGUAGES C ASM)

set(CMAKE_C_STANDARD 17)

if(NOT MCU_TYPE)
    set(MCU_TYPE attiny13a)
endif()

if(NOT MCU_PROGRAMMER_SPEED)
    set(MCU_PROGRAMMER_SPEED 256kHz)
endif()

if(NOT MCU_PROGRAMMER)
    set(MCU_PROGRAMMER usbasp)
endif()

if(NOT MCU_PROGRAMMER_PORT)
    set(MCU_PROGRAMMER_PORT /dev/usb/lp0)
endif()

set(SOURCE_FILES main.c)

########################################################################################################################

find_program(MCU_CC          avr-gcc     REQUIRED)
find_program(MCU_CXX         avr-g++     REQUIRED)
find_program(MCU_UPLOAD_TOOL avrdude     REQUIRED)
find_program(MCU_OBJCOPY     avr-objcopy REQUIRED)
find_program(MCU_SIZE        avr-size    REQUIRED)
find_program(MCU_OBJDUMP     avr-objdump REQUIRED)

set(CMAKE_C_COMPILER   ${MCU_CC})
set(CMAKE_CXX_COMPILER ${MCU_CXX})

if(DEFINED $ENV{AVR_ROOT_PATH})
    set(AVR_ROOT_PATH $ENV{AVR_ROOT_PATH})
else()
    if(EXISTS "/usr/avr")
        set(AVR_ROOT_PATH "/usr/avr")
    elseif(EXISTS "/opt/local/avr")
        set(AVR_ROOT_PATH "/opt/local/avr")
    elseif(EXISTS "/usr/lib/avr")
        set(AVR_ROOT_PATH "/usr/lib/avr")
    else()
        message(FATAL_ERROR "Please set AVR_ROOT_PATH in your environment.")
    endif()
endif()

set(CMAKE_SYSTEM_INCLUDE_PATH "${AVR_ROOT_PATH}/include")
set(CMAKE_SYSTEM_LIBRARY_PATH "${AVR_ROOT_PATH}/lib")

########################################################################################################################

set(MCU_FLAGS -c ${MCU_PROGRAMMER} -p ${MCU_TYPE} -P ${MCU_PROGRAMMER_PORT} -B ${MCU_PROGRAMMER_SPEED})

if(NOT CMAKE_BUILD_TYPE OR NOT (CMAKE_BUILD_TYPE MATCHES Release OR CMAKE_BUILD_TYPE MATCHES Debug))
    set(CMAKE_BUILD_TYPE Debug)
endif()

if(CMAKE_BUILD_TYPE MATCHES Release)
    set(CMAKE_C_FLAGS_RELEASE   "-Os")
    set(CMAKE_CXX_FLAGS_RELEASE "-Os")
endif()

if(CMAKE_BUILD_TYPE MATCHES Debug)
    set(CMAKE_C_FLAGS_DEBUG   "-O0 -save-temps -g -gdwarf-3 -gstrict-dwarf")
    set(CMAKE_CXX_FLAGS_DEBUG "-O0 -save-temps -g -gdwarf-3 -gstrict-dwarf")
endif()

########################################################################################################################

function(add_mcu_executable EXECUTABLE_NAME)
    if(NOT ARGN)
        message(FATAL_ERROR "No source files given for ${EXECUTABLE_NAME}")
    endif()

    set(elf_file    ${MCU_TYPE}-${EXECUTABLE_NAME}.elf)
    set(map_file    ${MCU_TYPE}-${EXECUTABLE_NAME}.map)
    set(hex_file    ${MCU_TYPE}-${EXECUTABLE_NAME}.hex)
    set(eeprom_file ${MCU_TYPE}-${EXECUTABLE_NAME}-eeprom.hex)

    add_executable(${elf_file} EXCLUDE_FROM_ALL ${ARGN})
    set_target_properties(${elf_file} PROPERTIES
            COMPILE_FLAGS "-mmcu=${MCU_TYPE}"
            LINK_FLAGS    "-mmcu=${MCU_TYPE} -Wl,--gc-sections -mrelax -Wl,-Map,${map_file}")

    add_custom_command(OUTPUT ${hex_file}
            COMMAND ${MCU_OBJCOPY} -j .text -j .data -O ihex ${elf_file} ${hex_file}
            DEPENDS ${elf_file})

    add_custom_command(OUTPUT ${eeprom_file}
            COMMAND ${MCU_OBJCOPY} -j .eeprom --set-section-flags=.eeprom=alloc,load
            --change-section-lma .eeprom=0 --no-change-warnings
            -O ihex ${elf_file} ${eeprom_file}
            DEPENDS ${elf_file})

    add_custom_target(upload_hex
            ${MCU_UPLOAD_TOOL} ${MCU_FLAGS} -v -U flash:w:${hex_file}
            DEPENDS ${hex_file})

    add_custom_target(upload_eeprom
            ${MCU_UPLOAD_TOOL} ${MCU_FLAGS} -v -U eeprom:w:${eeprom_file}
            DEPENDS ${eeprom_file})

endfunction()

add_mcu_executable(avr_blink main.c)