Example code for Simple Serial Communications With AVR Libc blog entry.
This commit is contained in:
Mika Tuupola
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501
blog/simple_usart/Makefile
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501
blog/simple_usart/Makefile
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@ -0,0 +1,501 @@
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# ----------------------------------------------------------------------------
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# Makefile based on WinAVR Makefile Template written by Eric B. Weddington,
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# Jörg Wunsch, et al.
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#
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# Adjust F_CPU below to the clock frequency in Mhz of your AVR target
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#
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# Adjust the size of the uart receive and transmit ringbuffer in bytes using
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# defines -DUART_RX_BUFFER_SIZE=128 and -DUART_TX_BUFFER_SIZE=128 in the
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# CDEF section below
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#
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#----------------------------------------------------------------------------
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# On command line:
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#
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# make all = Make software.
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#
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# make clean = Clean out built project files.
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#
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# make coff = Convert ELF to AVR COFF.
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#
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# make extcoff = Convert ELF to AVR Extended COFF.
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#
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# make program = Download the hex file to the device, using avrdude.
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# Please customize the avrdude settings below first!
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#
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# make debug = Start either simulavr or avarice as specified for debugging,
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# with avr-gdb or avr-insight as the front end for debugging.
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#
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# make filename.s = Just compile filename.c into the assembler code only.
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#
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# make filename.i = Create a preprocessed source file for use in submitting
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# bug reports to the GCC project.
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#
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# To rebuild project do "make clean" then "make all".
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#----------------------------------------------------------------------------
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# MCU name
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MCU = atmega328p
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# Processor frequency.
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# This will define a symbol, F_CPU, in all source code files equal to the
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# processor frequency. You can then use this symbol in your source code to
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# calculate timings. Do NOT tack on a 'UL' at the end, this will be done
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# automatically to create a 32-bit value in your source code.
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F_CPU = 16000000
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# Output format. (can be srec, ihex, binary)
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FORMAT = ihex
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# Target file name (without extension).
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TARGET = main
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# List C source files here. (C dependencies are automatically generated.)
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SRC = $(TARGET).c uart.c
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# List Assembler source files here.
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# Make them always end in a capital .S. Files ending in a lowercase .s
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# will not be considered source files but generated files (assembler
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# output from the compiler), and will be deleted upon "make clean"!
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# Even though the DOS/Win* filesystem matches both .s and .S the same,
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# it will preserve the spelling of the filenames, and gcc itself does
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# care about how the name is spelled on its command-line.
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ASRC =
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# Optimization level, can be [0, 1, 2, 3, s].
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# 0 = turn off optimization. s = optimize for size.
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# (Note: 3 is not always the best optimization level. See avr-libc FAQ.)
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OPT = s
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# Debugging format.
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# Native formats for AVR-GCC's -g are dwarf-2 [default] or stabs.
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# AVR Studio 4.10 requires dwarf-2.
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# AVR [Extended] COFF format requires stabs, plus an avr-objcopy run.
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DEBUG = dwarf-2
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# List any extra directories to look for include files here.
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# Each directory must be seperated by a space.
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# Use forward slashes for directory separators.
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# For a directory that has spaces, enclose it in quotes.
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EXTRAINCDIRS =
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# Compiler flag to set the C Standard level.
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# c89 = "ANSI" C
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# gnu89 = c89 plus GCC extensions
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# c99 = ISO C99 standard (not yet fully implemented)
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# gnu99 = c99 plus GCC extensions
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CSTANDARD = -std=gnu99
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# Place -D or -U options here
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CDEFS = -DF_CPU=$(F_CPU)UL
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# uncomment and adapt these line if you want different UART library buffer size
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#CDEFS += -DUART_RX_BUFFER_SIZE=128
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#CDEFS += -DUART_TX_BUFFER_SIZE=128
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# Place -I options here
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CINCS =
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#---------------- Compiler Options ----------------
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# -g*: generate debugging information
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# -O*: optimization level
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# -f...: tuning, see GCC manual and avr-libc documentation
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# -Wall...: warning level
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# -Wa,...: tell GCC to pass this to the assembler.
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# -adhlns...: create assembler listing
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CFLAGS = -g$(DEBUG)
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CFLAGS += $(CDEFS) $(CINCS)
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CFLAGS += -O$(OPT)
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CFLAGS += -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums
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CFLAGS += -Wall -Wstrict-prototypes
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CFLAGS += -Wa,-adhlns=$(<:.c=.lst)
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CFLAGS += $(patsubst %,-I%,$(EXTRAINCDIRS))
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CFLAGS += $(CSTANDARD)
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#---------------- Assembler Options ----------------
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# -Wa,...: tell GCC to pass this to the assembler.
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# -ahlms: create listing
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# -gstabs: have the assembler create line number information; note that
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# for use in COFF files, additional information about filenames
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# and function names needs to be present in the assembler source
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# files -- see avr-libc docs [FIXME: not yet described there]
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ASFLAGS = -Wa,-adhlns=$(<:.S=.lst),-gstabs
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#---------------- Library Options ----------------
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# Minimalistic printf version
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PRINTF_LIB_MIN = -Wl,-u,vfprintf -lprintf_min
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# Floating point printf version (requires MATH_LIB = -lm below)
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PRINTF_LIB_FLOAT = -Wl,-u,vfprintf -lprintf_flt
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# If this is left blank, then it will use the Standard printf version.
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PRINTF_LIB =
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#PRINTF_LIB = $(PRINTF_LIB_MIN)
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#PRINTF_LIB = $(PRINTF_LIB_FLOAT)
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# Minimalistic scanf version
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SCANF_LIB_MIN = -Wl,-u,vfscanf -lscanf_min
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# Floating point + %[ scanf version (requires MATH_LIB = -lm below)
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SCANF_LIB_FLOAT = -Wl,-u,vfscanf -lscanf_flt
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# If this is left blank, then it will use the Standard scanf version.
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SCANF_LIB =
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#SCANF_LIB = $(SCANF_LIB_MIN)
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#SCANF_LIB = $(SCANF_LIB_FLOAT)
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MATH_LIB = -lm
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#---------------- External Memory Options ----------------
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# 64 KB of external RAM, starting after internal RAM (ATmega128!),
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# used for variables (.data/.bss) and heap (malloc()).
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#EXTMEMOPTS = -Wl,-Tdata=0x801100,--defsym=__heap_end=0x80ffff
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# 64 KB of external RAM, starting after internal RAM (ATmega128!),
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# only used for heap (malloc()).
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#EXTMEMOPTS = -Wl,--defsym=__heap_start=0x801100,--defsym=__heap_end=0x80ffff
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EXTMEMOPTS =
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#---------------- Linker Options ----------------
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# -Wl,...: tell GCC to pass this to linker.
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# -Map: create map file
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# --cref: add cross reference to map file
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LDFLAGS = -Wl,-Map=$(TARGET).map,--cref
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LDFLAGS += $(EXTMEMOPTS)
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LDFLAGS += $(PRINTF_LIB) $(SCANF_LIB) $(MATH_LIB)
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#---------------- Programming Options (avrdude) ----------------
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# Programming hardware: alf avr910 avrisp bascom bsd
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# dt006 pavr picoweb pony-stk200 sp12 stk200 stk500
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#
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# Type: avrdude -c ?
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# to get a full listing.
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#
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AVRDUDE_PROGRAMMER = arduino
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# com1 = serial port. Use lpt1 to connect to parallel port.
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AVRDUDE_PORT = /dev/tty.usb* # programmer connected to serial device
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AVRDUDE_WRITE_FLASH = -U flash:w:$(TARGET).hex
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#AVRDUDE_WRITE_EEPROM = -U eeprom:w:$(TARGET).eep
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# Uncomment the following if you want avrdude's erase cycle counter.
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# Note that this counter needs to be initialized first using -Yn,
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# see avrdude manual.
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#AVRDUDE_ERASE_COUNTER = -y
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# Uncomment the following if you do /not/ wish a verification to be
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# performed after programming the device.
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#AVRDUDE_NO_VERIFY = -V
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# Increase verbosity level. Please use this when submitting bug
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# reports about avrdude. See <http://savannah.nongnu.org/projects/avrdude>
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# to submit bug reports.
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#AVRDUDE_VERBOSE = -v -v
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AVRDUDE_FLAGS = -p $(MCU) -P $(AVRDUDE_PORT) -c $(AVRDUDE_PROGRAMMER) -b 57600
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AVRDUDE_FLAGS += $(AVRDUDE_NO_VERIFY)
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AVRDUDE_FLAGS += $(AVRDUDE_VERBOSE)
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AVRDUDE_FLAGS += $(AVRDUDE_ERASE_COUNTER)
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#---------------- Debugging Options ----------------
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# For simulavr only - target MCU frequency.
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DEBUG_MFREQ = $(F_CPU)
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# Set the DEBUG_UI to either gdb or insight.
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# DEBUG_UI = gdb
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DEBUG_UI = insight
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# Set the debugging back-end to either avarice, simulavr.
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DEBUG_BACKEND = avarice
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#DEBUG_BACKEND = simulavr
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# GDB Init Filename.
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GDBINIT_FILE = __avr_gdbinit
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# When using avarice settings for the JTAG
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JTAG_DEV = /dev/com1
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# Debugging port used to communicate between GDB / avarice / simulavr.
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DEBUG_PORT = 4242
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# Debugging host used to communicate between GDB / avarice / simulavr, normally
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# just set to localhost unless doing some sort of crazy debugging when
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# avarice is running on a different computer.
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DEBUG_HOST = localhost
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#============================================================================
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# Define programs and commands.
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SHELL = sh
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CC = avr-gcc
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OBJCOPY = avr-objcopy
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OBJDUMP = avr-objdump
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SIZE = avr-size
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NM = avr-nm
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AVRDUDE = avrdude
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REMOVE = rm -f
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COPY = cp
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WINSHELL = cmd
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# Define Messages
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# English
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MSG_ERRORS_NONE = Errors: none
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MSG_BEGIN = -------- begin --------
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MSG_END = -------- end --------
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MSG_SIZE_BEFORE = Size before:
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MSG_SIZE_AFTER = Size after:
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MSG_COFF = Converting to AVR COFF:
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MSG_EXTENDED_COFF = Converting to AVR Extended COFF:
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MSG_FLASH = Creating load file for Flash:
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MSG_EEPROM = Creating load file for EEPROM:
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MSG_EXTENDED_LISTING = Creating Extended Listing:
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MSG_SYMBOL_TABLE = Creating Symbol Table:
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MSG_LINKING = Linking:
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MSG_COMPILING = Compiling:
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MSG_ASSEMBLING = Assembling:
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MSG_CLEANING = Cleaning project:
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# Define all object files.
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OBJ = $(SRC:.c=.o) $(ASRC:.S=.o)
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# Define all listing files.
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LST = $(SRC:.c=.lst) $(ASRC:.S=.lst)
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# Compiler flags to generate dependency files.
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GENDEPFLAGS = -MD -MP -MF .dep/$(@F).d
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# Combine all necessary flags and optional flags.
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# Add target processor to flags.
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ALL_CFLAGS = -mmcu=$(MCU) -I. $(CFLAGS) $(GENDEPFLAGS)
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ALL_ASFLAGS = -mmcu=$(MCU) -I. -x assembler-with-cpp $(ASFLAGS)
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# Default target.
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all: begin gccversion sizebefore build sizeafter end
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build: elf hex eep lss sym
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elf: $(TARGET).elf
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hex: $(TARGET).hex
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eep: $(TARGET).eep
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lss: $(TARGET).lss
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sym: $(TARGET).sym
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# Eye candy.
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# AVR Studio 3.x does not check make's exit code but relies on
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# the following magic strings to be generated by the compile job.
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begin:
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@echo
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@echo $(MSG_BEGIN)
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end:
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@echo $(MSG_END)
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@echo
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# Display size of file.
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HEXSIZE = $(SIZE) --target=$(FORMAT) $(TARGET).hex
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ELFSIZE = $(SIZE) -A $(TARGET).elf
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AVRMEM = avr-mem.sh $(TARGET).elf $(MCU)
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sizebefore:
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@if test -f $(TARGET).elf; then echo; echo $(MSG_SIZE_BEFORE); $(ELFSIZE); \
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$(AVRMEM) 2>/dev/null; echo; fi
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sizeafter:
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@if test -f $(TARGET).elf; then echo; echo $(MSG_SIZE_AFTER); $(ELFSIZE); \
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$(AVRMEM) 2>/dev/null; echo; fi
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# Display compiler version information.
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gccversion :
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@$(CC) --version
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# Program the device.
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program: $(TARGET).hex $(TARGET).eep
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$(AVRDUDE) $(AVRDUDE_FLAGS) $(AVRDUDE_WRITE_FLASH) $(AVRDUDE_WRITE_EEPROM)
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|
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# Generate avr-gdb config/init file which does the following:
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# define the reset signal, load the target file, connect to target, and set
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# a breakpoint at main().
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gdb-config:
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@$(REMOVE) $(GDBINIT_FILE)
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@echo define reset >> $(GDBINIT_FILE)
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@echo SIGNAL SIGHUP >> $(GDBINIT_FILE)
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@echo end >> $(GDBINIT_FILE)
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@echo file $(TARGET).elf >> $(GDBINIT_FILE)
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@echo target remote $(DEBUG_HOST):$(DEBUG_PORT) >> $(GDBINIT_FILE)
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ifeq ($(DEBUG_BACKEND),simulavr)
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@echo load >> $(GDBINIT_FILE)
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endif
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@echo break main >> $(GDBINIT_FILE)
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debug: gdb-config $(TARGET).elf
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ifeq ($(DEBUG_BACKEND), avarice)
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@echo Starting AVaRICE - Press enter when "waiting to connect" message displays.
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@$(WINSHELL) /c start avarice --jtag $(JTAG_DEV) --erase --program --file \
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$(TARGET).elf $(DEBUG_HOST):$(DEBUG_PORT)
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@$(WINSHELL) /c pause
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else
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@$(WINSHELL) /c start simulavr --gdbserver --device $(MCU) --clock-freq \
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$(DEBUG_MFREQ) --port $(DEBUG_PORT)
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endif
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@$(WINSHELL) /c start avr-$(DEBUG_UI) --command=$(GDBINIT_FILE)
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|
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|
||||
|
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|
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# Convert ELF to COFF for use in debugging / simulating in AVR Studio or VMLAB.
|
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COFFCONVERT=$(OBJCOPY) --debugging \
|
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--change-section-address .data-0x800000 \
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--change-section-address .bss-0x800000 \
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--change-section-address .noinit-0x800000 \
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--change-section-address .eeprom-0x810000
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coff: $(TARGET).elf
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@echo
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@echo $(MSG_COFF) $(TARGET).cof
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$(COFFCONVERT) -O coff-avr $< $(TARGET).cof
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|
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|
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extcoff: $(TARGET).elf
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@echo
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@echo $(MSG_EXTENDED_COFF) $(TARGET).cof
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$(COFFCONVERT) -O coff-ext-avr $< $(TARGET).cof
|
||||
|
||||
|
||||
|
||||
# Create final output files (.hex, .eep) from ELF output file.
|
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%.hex: %.elf
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@echo
|
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@echo $(MSG_FLASH) $@
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$(OBJCOPY) -O $(FORMAT) -R .eeprom $< $@
|
||||
|
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%.eep: %.elf
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@echo
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@echo $(MSG_EEPROM) $@
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||||
-$(OBJCOPY) -j .eeprom --set-section-flags=.eeprom="alloc,load" \
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--change-section-lma .eeprom=0 -O $(FORMAT) $< $@
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||||
|
||||
# Create extended listing file from ELF output file.
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||||
%.lss: %.elf
|
||||
@echo
|
||||
@echo $(MSG_EXTENDED_LISTING) $@
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||||
$(OBJDUMP) -h -S $< > $@
|
||||
|
||||
# Create a symbol table from ELF output file.
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%.sym: %.elf
|
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@echo
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@echo $(MSG_SYMBOL_TABLE) $@
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$(NM) -n $< > $@
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|
||||
|
||||
|
||||
# Link: create ELF output file from object files.
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.SECONDARY : $(TARGET).elf
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.PRECIOUS : $(OBJ)
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%.elf: $(OBJ)
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||||
@echo
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@echo $(MSG_LINKING) $@
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$(CC) $(ALL_CFLAGS) $^ --output $@ $(LDFLAGS)
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||||
|
||||
|
||||
# Compile: create object files from C source files.
|
||||
%.o : %.c
|
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@echo
|
||||
@echo $(MSG_COMPILING) $<
|
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$(CC) -c $(ALL_CFLAGS) $< -o $@
|
||||
|
||||
|
||||
# Compile: create assembler files from C source files.
|
||||
%.s : %.c
|
||||
$(CC) -S $(ALL_CFLAGS) $< -o $@
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||||
|
||||
|
||||
# Assemble: create object files from assembler source files.
|
||||
%.o : %.S
|
||||
@echo
|
||||
@echo $(MSG_ASSEMBLING) $<
|
||||
$(CC) -c $(ALL_ASFLAGS) $< -o $@
|
||||
|
||||
# Create preprocessed source for use in sending a bug report.
|
||||
%.i : %.c
|
||||
$(CC) -E -mmcu=$(MCU) -I. $(CFLAGS) $< -o $@
|
||||
|
||||
|
||||
# Target: clean project.
|
||||
clean: begin clean_list end
|
||||
|
||||
clean_list :
|
||||
@echo
|
||||
@echo $(MSG_CLEANING)
|
||||
$(REMOVE) $(TARGET).hex
|
||||
$(REMOVE) $(TARGET).eep
|
||||
$(REMOVE) $(TARGET).cof
|
||||
$(REMOVE) $(TARGET).elf
|
||||
$(REMOVE) $(TARGET).map
|
||||
$(REMOVE) $(TARGET).sym
|
||||
$(REMOVE) $(TARGET).lss
|
||||
$(REMOVE) $(OBJ)
|
||||
$(REMOVE) $(LST)
|
||||
$(REMOVE) $(SRC:.c=.s)
|
||||
$(REMOVE) $(SRC:.c=.d)
|
||||
$(REMOVE) .dep/*
|
||||
|
||||
|
||||
|
||||
# Include the dependency files.
|
||||
-include $(shell mkdir .dep 2>/dev/null) $(wildcard .dep/*)
|
||||
|
||||
|
||||
# Listing of phony targets.
|
||||
.PHONY : all begin finish end sizebefore sizeafter gccversion \
|
||||
build elf hex eep lss sym coff extcoff \
|
||||
clean clean_list program debug gdb-config
|
||||
|
||||
36
blog/simple_usart/main.c
Normal file
36
blog/simple_usart/main.c
Normal file
@ -0,0 +1,36 @@
|
||||
/*
|
||||
* Demonstration on how to redirect stdio to UART.
|
||||
*
|
||||
* http://appelsiini.net/2011/simple-usart-with-avr-libc
|
||||
*
|
||||
* To compile and upload run: make clean; make; make program;
|
||||
* Connect to serial with: screen /dev/tty.usbserial-*
|
||||
*
|
||||
* Copyright 2011 Mika Tuupola
|
||||
*
|
||||
* Licensed under the MIT license:
|
||||
* http://www.opensource.org/licenses/mit-license.php
|
||||
*
|
||||
*/
|
||||
|
||||
#include <stdio.h>
|
||||
|
||||
#include "main.h"
|
||||
#include "uart.h"
|
||||
|
||||
int main(void) {
|
||||
|
||||
uart_init();
|
||||
stdout = &uart_output;
|
||||
stdin = &uart_input;
|
||||
|
||||
char input;
|
||||
|
||||
while(1) {
|
||||
puts("Hello world!");
|
||||
input = getchar();
|
||||
printf("You wrote %c\n", input);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
1
blog/simple_usart/main.h
Normal file
1
blog/simple_usart/main.h
Normal file
@ -0,0 +1 @@
|
||||
int main(void);
|
||||
40
blog/simple_usart/uart.c
Normal file
40
blog/simple_usart/uart.c
Normal file
@ -0,0 +1,40 @@
|
||||
#include <avr/io.h>
|
||||
#include <stdio.h>
|
||||
|
||||
#ifndef F_CPU
|
||||
#define F_CPU 16000000UL
|
||||
#endif
|
||||
|
||||
#ifndef BAUD
|
||||
#define BAUD 9600
|
||||
#endif
|
||||
#include <util/setbaud.h>
|
||||
|
||||
/* http://www.cs.mun.ca/~rod/Winter2007/4723/notes/serial/serial.html */
|
||||
|
||||
void uart_init(void) {
|
||||
UBRR0H = UBRRH_VALUE;
|
||||
UBRR0L = UBRRL_VALUE;
|
||||
|
||||
#if USE_2X
|
||||
UCSR0A |= _BV(U2X0);
|
||||
#else
|
||||
UCSR0A &= ~(_BV(U2X0));
|
||||
#endif
|
||||
|
||||
UCSR0C = _BV(UCSZ01) | _BV(UCSZ00); /* 8-bit data */
|
||||
UCSR0B = _BV(RXEN0) | _BV(TXEN0); /* Enable RX and TX */
|
||||
}
|
||||
|
||||
void uart_putchar(char c, FILE *stream) {
|
||||
if (c == '\n') {
|
||||
uart_putchar('\r', stream);
|
||||
}
|
||||
loop_until_bit_is_set(UCSR0A, UDRE0);
|
||||
UDR0 = c;
|
||||
}
|
||||
|
||||
char uart_getchar(FILE *stream) {
|
||||
loop_until_bit_is_set(UCSR0A, RXC0);
|
||||
return UDR0;
|
||||
}
|
||||
9
blog/simple_usart/uart.h
Normal file
9
blog/simple_usart/uart.h
Normal file
@ -0,0 +1,9 @@
|
||||
void uart_putchar(char c, FILE *stream);
|
||||
char uart_getchar(FILE *stream);
|
||||
|
||||
void uart_init(void);
|
||||
|
||||
/* http://www.ermicro.com/blog/?p=325 */
|
||||
|
||||
FILE uart_output = FDEV_SETUP_STREAM(uart_putchar, NULL, _FDEV_SETUP_WRITE);
|
||||
FILE uart_input = FDEV_SETUP_STREAM(NULL, uart_getchar, _FDEV_SETUP_READ);
|
||||
Loading…
Reference in New Issue
Block a user