Update sample Makefile for Teensy 4.0

teensy4/Makefile

-CPUARCH = cortex-m7
-DEFS = -DUSB_SERIAL -D__IMXRT1052__ -DTEENSYDUINO=145 -DARDUINO=10808 -DF_CPU=396000000 -DLAYOUT_US_ENGLISH
-SECTIONS = -ffunction-sections -fdata-sections
-CPPFLAGS = -Wall -g -O2 $(SECTIONS) -mcpu=$(CPUARCH) -mthumb -mfloat-abi=hard -mfpu=fpv4-sp-d16 -fsingle-precision-constant -I. $(DEFS)
-CXXFLAGS = -std=gnu++14 -felide-constructors -fno-exceptions -fno-rtti
-LDFLAGS = -Wl,--gc-sections,--print-gc-sections,--print-memory-usage --specs=nano.specs -nostdlib -nostartfiles -Timxrt.ld
+# Teensyduino Core Library
+# http://www.pjrc.com/teensy/
+# Copyright (c) 2019 PJRC.COM, LLC.
+#
+# 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:
+#
+# 1. The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# 2. If the Software is incorporated into a build system that allows
+# selection among a list of target devices, then similar target
+# devices manufactured by PJRC.COM must be included in the list of
+# target devices and selectable in the same manner.
+#
+# 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.
 
-C_FILES := $(wildcard *.c)
-CPP_FILES := $(wildcard *.cpp)
+# set your MCU type here, or make command line `make MCU=IMXRT1062`
+MCU=IMXRT1062
 
-OBJS := $(C_FILES:.c=.o) $(CPP_FILES:.cpp=.o)
+# The name of your project (used to name the compiled .hex file)
+TARGET = main
+
+# configurable options
+OPTIONS = -DF_CPU=600000000 -DUSB_SERIAL -DLAYOUT_US_ENGLISH -DUSING_MAKEFILE
+
+# options needed by many Arduino libraries to configure for Teensy 4.0
+OPTIONS += -D__$(MCU)__ -DARDUINO=10810 -DTEENSYDUINO=149
+
+# for Cortex M7 with single & double precision FPU
+CPUOPTIONS = -mcpu=cortex-m7 -mfloat-abi=hard -mfpu=fpv5-d16 -mthumb
+
+# use this for a smaller, no-float printf
+#SPECS = --specs=nano.specs
+
+# Other Makefiles and project templates for Teensy 3.x:
+#
+# https://github.com/apmorton/teensy-template
+# https://github.com/xxxajk/Arduino_Makefile_master
+# https://github.com/JonHylands/uCee
 
-ARDUINOPATH = /home/paul/teensy/arduino-1.8.8
+
+#************************************************************************
+# Location of Teensyduino utilities, Toolchain, and Arduino Libraries.
+# To use this makefile without Arduino, copy the resources from these
+# locations and edit the pathnames.  The rest of Arduino is not needed.
+#************************************************************************
+
+# Those that specify a NO_ARDUINO environment variable will
+# be able to use this Makefile with no Arduino dependency.
+# Please note that if ARDUINOPATH was set, it will override
+# the NO_ARDUINO behaviour.
+ifndef NO_ARDUINO
+# Path to your arduino installation
+ARDUINOPATH ?= ../../../../..
+endif
+
+ifdef ARDUINOPATH
+
+# path location for Teensy Loader, teensy_post_compile and teensy_reboot (on Linux)
+TOOLSPATH = $(abspath $(ARDUINOPATH)/hardware/tools)
+
+# path location for Arduino libraries (currently not used)
+LIBRARYPATH = $(abspath $(ARDUINOPATH)/libraries)
+
+# path location for the arm-none-eabi compiler
 COMPILERPATH = $(abspath $(ARDUINOPATH)/hardware/tools/arm/bin)
+
+else
+# Default to the normal GNU/Linux compiler path if NO_ARDUINO
+# and ARDUINOPATH was not set.
+COMPILERPATH ?= /usr/bin
+
+endif
+
+#************************************************************************
+# Settings below this point usually do not need to be edited
+#************************************************************************
+
+# CPPFLAGS = compiler options for C and C++
+CPPFLAGS = -Wall -g -O2 $(CPUOPTIONS) -MMD $(OPTIONS) -I. -ffunction-sections -fdata-sections
+
+# compiler options for C++ only
+CXXFLAGS = -std=gnu++14 -felide-constructors -fno-exceptions -fpermissive -fno-rtti -Wno-error=narrowing
+
+# compiler options for C only
+CFLAGS =
+
+# linker options
+LDFLAGS = -Os -Wl,--gc-sections,--relax $(SPECS) $(CPUOPTIONS) -T$(MCU_LD)
+
+# additional libraries to link
+LIBS = -larm_cortexM7lfsp_math -lm -lstdc++
+
+
+# names for the compiler programs
 CC = $(COMPILERPATH)/arm-none-eabi-gcc
 CXX = $(COMPILERPATH)/arm-none-eabi-g++
 OBJCOPY = $(COMPILERPATH)/arm-none-eabi-objcopy
-OBJDUMP = $(COMPILERPATH)/arm-none-eabi-objdump
 SIZE = $(COMPILERPATH)/arm-none-eabi-size
-AR = $(COMPILERPATH)/arm-none-eabi-gcc-ar
 
-all: Blink.elf
+# automatically create lists of the sources and objects
+# TODO: this does not handle Arduino libraries yet...
+C_FILES := $(wildcard *.c)
+CPP_FILES := $(wildcard *.cpp)
+OBJS := $(C_FILES:.c=.o) $(CPP_FILES:.cpp=.o)
 
-Blink.elf: Blink.o core.a
-	$(CC) $(CPPFLAGS) $(LDFLAGS) -o $@ $^ -lm
-	#$(CC) $(CPPFLAGS) $(LDFLAGS) -o $@ Blink.o $(OBJS) -lm
-	$(OBJDUMP) -d -S -C $@ > Blink.lst
-	$(OBJDUMP) -t -C $@ > Blink.sym
-	$(OBJCOPY) -O ihex -R .eeprom $@ Blink.hex
-	$(SIZE) $@
 
-core.a: $(OBJS)
-	$(AR) rcs core.a $(OBJS)
+# the actual makefile rules (all .o files built by GNU make's default implicit rules)
 
+all: $(TARGET).hex
 
-clean:
-	rm -f *.o *.d core.a *.elf *.lst *.sym *.hex
+$(TARGET).elf: $(OBJS) $(MCU_LD)
+	$(CC) $(LDFLAGS) -o $@ $(OBJS) $(LIBS)
 
+%.hex: %.elf
+	$(SIZE) $<
+	$(OBJCOPY) -O ihex -R .eeprom $< $@
+ifneq (,$(wildcard $(TOOLSPATH)))
+	$(TOOLSPATH)/teensy_post_compile -file=$(basename $@) -path=$(shell pwd) -tools=$(TOOLSPATH)
+	-$(TOOLSPATH)/teensy_reboot
+endif
+
+# compiler generated dependency info
+-include $(OBJS:.o=.d)
+
+# make "MCU" lower case
+LOWER_MCU := $(subst A,a,$(subst B,b,$(subst C,c,$(subst D,d,$(subst E,e,$(subst F,f,$(subst G,g,$(subst H,h,$(subst I,i,$(subst J,j,$(subst K,k,$(subst L,l,$(subst M,m,$(subst N,n,$(subst O,o,$(subst P,p,$(subst Q,q,$(subst R,r,$(subst S,s,$(subst T,t,$(subst U,u,$(subst V,v,$(subst W,w,$(subst X,x,$(subst Y,y,$(subst Z,z,$(MCU)))))))))))))))))))))))))))
+MCU_LD = $(LOWER_MCU).ld
+
+clean:
+	rm -f *.o *.d $(TARGET).elf $(TARGET).hex