sconstruct

from __future__ import print_function

import json
import os
from pprint import pprint
import sys


# Guess file names from folder names
parent_folder = os.path.basename(os.getcwd())
project_name = parent_folder


# Hardware configuration
file_name = 'hardware.json'
hardware = {
    'mhz': 1,
    'mcu': 'atmega328p',
    'programmer': 'usbasp',
}


# Override defaults?
try:
    with open(file_name) as fp:
        hardware.update(json.load(fp))
except IOError:
    message = "No '{}' configuration found. Defaults used."
    print(message.format(file_name), file=sys.stderr)


# Print hardware configuration
message = "Program '{mcu}' running at {mhz:,}MHz using '{programmer}' ISP".format(**hardware)
print("="*len(message))
print(message)
print("="*len(message))


# Project variables
config = Variables()
config.Add('mcu', 'Microcontroller', hardware['mcu'])
config.Add('hz', 'CPU frequency in Hz', int(hardware['mhz']*1e6))
config.Add('programmer', 'ISP Programmer', hardware['programmer'])


# Initialise build environment
cflags = (
    # Chip type, speed, and communication speed.
    '-mmcu=${mcu} -DF_CPU=${hz}UL -DBAUD=9600UL -I. '
    # Small code, debug info, C-standard, lots-o-warnings.
    '-Os -g -std=gnu11 -Wall '
    # Use short (8-bit) data types
    '-funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums '
    # Splits up object files per function
    '-ffunction-sections -fdata-sections '
)

elf = Builder(action="avr-gcc -Wl,--gc-sections -I. -mmcu=${mcu} $SOURCE  -o $TARGET")
hex = Builder(action="avr-objcopy -j .text -j .data -O ihex $SOURCE $TARGET")
builders = {'elf': elf, 'hex': hex}

env = Environment(
    BUILDERS=builders,
    CC='avr-gcc ',
    CFLAGS=cflags,
    ENV={'PATH': os.environ['PATH']},
    variables = config,
)


# Build Targets
main_c = project_name + '.c'
main_o = project_name + '.o'
main_elf = project_name + '.elf'
main_hex = project_name + '.hex'
env.Object(target=Glob('*.c'))
env.elf(main_elf, main_o)
env.hex(main_hex, main_elf)


# Size
Default('size')
env.Command('size', main_elf, "avr-size $SOURCE")


# Flash the thing!
env.Command('flash', main_hex, "avrdude -c ${programmer} -p ${mcu} -U flash:w:$SOURCE")