avr-gcc -mmcu 관련 작동 내용

avt studio 4만 다뤄봐서.. 5 부터는 어떻게 되는진 모르겠지만

윈도우에서는  -D를 통해서 cpu 종류와 클럭을 넣어주었는데

리눅스에서는 컴파일러의 도움을 받아 mcu 종류를 넣어주면 알아서 확장해서 사용한다.

그래서 win-avr과 같은 종류별로 헤더를 찾는 수고로움이 더는 장점은 있지만

빌드 과정에서 설정하게 되어 있어서 모르면 더 복잡할지도..

-mmcu=architecture Note that when only using -mmcu=architecture but no -mmcu=MCU type, including the file <avr/io.h> cannot work since it cannot decide which device's definitions to select. Architecture Macros avr5 AVR_ARCH=5 AVR_MEGA [5] AVR_ENHANCED [5] AVR_HAVE_JMP_CALL [4] AVR_HAVE_MOVW [1] AVR_HAVE_LPMX [1] AVR_HAVE_MUL [1] AVR_2_BYTE_PC [2] avr51 AVR_ARCH=51 AVR_MEGA [5] AVR_ENHANCED [5] AVR_HAVE_JMP_CALL [4] AVR_HAVE_MOVW [1] AVR_HAVE_LPMX [1] AVR_HAVE_MUL [1] AVR_HAVE_RAMPZ [4] AVR_HAVE_ELPM [4] AVR_HAVE_ELPMX [4] AVR_2_BYTE_PC [2] -mmcu=MCU type The following MCU types are currently understood by avr-gcc. The table matches them against the corresponding avr-gcc architecture name, and shows the preprocessor symbol declared by the -mmcu option.  Architecture MCU name    Macro avr5/avr51 [3] atmega128   __AVR_ATmega128__

[링크 : http://www.nongnu.org/avr-libc/user-manual/using_tools.html]

#define AVR 1 #define __AVR 1 #define __AVR_ARCH__ 5 #define __AVR_ATmega128__ 1 #define __AVR_ENHANCED__ 1 #define __AVR_MEGA__ 1 #define __AVR__ 1 #define __CHAR_BIT__ 8 #define __DBL_DENORM_MIN__ 1.40129846e-45 #define __DBL_DIG__ 6 #define __DBL_EPSILON__ 1.19209290e-7 #define __DBL_HAS_INFINITY__ 1 #define __DBL_HAS_QUIET_NAN__ 1 #define __DBL_MANT_DIG__ 24 #define __DBL_MAX_10_EXP__ 38 #define __DBL_MAX_EXP__ 128 #define __DBL_MAX__ 3.40282347e+38 #define __DBL_MIN_10_EXP__ (-37) #define __DBL_MIN_EXP__ (-125) #define __DBL_MIN__ 1.17549435e-38 #define __DECIMAL_DIG__ 9 #define __FINITE_MATH_ONLY__ 0 #define __FLT_DENORM_MIN__ 1.40129846e-45F #define __FLT_DIG__ 6 #define __FLT_EPSILON__ 1.19209290e-7F #define __FLT_EVAL_METHOD__ 0 #define __FLT_HAS_INFINITY__ 1 #define __FLT_HAS_QUIET_NAN__ 1 #define __FLT_MANT_DIG__ 24 #define __FLT_MAX_10_EXP__ 38 #define __FLT_MAX_EXP__ 128 #define __FLT_MAX__ 3.40282347e+38F #define __FLT_MIN_10_EXP__ (-37) #define __FLT_MIN_EXP__ (-125) #define __FLT_MIN__ 1.17549435e-38F #define __FLT_RADIX__ 2 #define __GNUC_MINOR__ 1 #define __GNUC_PATCHLEVEL__ 0 #define __GNUC__ 4 #define __GXX_ABI_VERSION 1002 #define __INTMAX_MAX__ 9223372036854775807LL #define __INTMAX_TYPE__ long long int #define __INT_MAX__ 32767 #define __LDBL_DENORM_MIN__ 1.40129846e-45L #define __LDBL_DIG__ 6 #define __LDBL_EPSILON__ 1.19209290e-7L #define __LDBL_HAS_INFINITY__ 1 #define __LDBL_HAS_QUIET_NAN__ 1 #define __LDBL_MANT_DIG__ 24 #define __LDBL_MAX_10_EXP__ 38 #define __LDBL_MAX_EXP__ 128 #define __LDBL_MAX__ 3.40282347e+38L #define __LDBL_MIN_10_EXP__ (-37) #define __LDBL_MIN_EXP__ (-125) #define __LDBL_MIN__ 1.17549435e-38L #define __LONG_LONG_MAX__ 9223372036854775807LL #define __LONG_MAX__ 2147483647L #define __NO_INLINE__ 1 #define __PTRDIFF_TYPE__ int #define __REGISTER_PREFIX__  #define __SCHAR_MAX__ 127 #define __SHRT_MAX__ 32767 #define __SIZE_TYPE__ unsigned int #define __STDC_HOSTED__ 1 #define __STDC__ 1 #define __UINTMAX_TYPE__ long long unsigned int #define __USER_LABEL_PREFIX__  #define __USING_SJLJ_EXCEPTIONS__ 1 #define __VERSION__ "4.1.0" #define __WCHAR_MAX__ 32767 #define __WCHAR_TYPE__ int #define __WINT_TYPE__ unsigned int

[링크 : http://www.avrfreaks.net/forum/how-does-mmcumcutarget-work]