Next: Blackfin Options, Previous: ARM Options, Up: Submodel Options [Contents][Index]
For AVR® Development. CrossPack is a development environment for Atmel’s AVR® microcontrollers running on Apple’s Mac OS X, similar to AVR Studio on Windows. It consists of the GNU compiler suite, a C library for the AVR, the AVRDUDE uploader and several other useful tools.
Fortunately, gcc is supporting the AVR cpu for quite some time now and e.g. The WinAVR toolchain for AVR development under windows is based on this compiler. Many people have already ported these compilers to MacOS X incl. The fink project and others. $begingroup$ Get the avr-eclipse plugin, it integrates nicely with avrdude and avr-gcc so you end up with a nice IDE on top of a good, free compiler. $endgroup$ – dren.dk Mar 25 '11 at 8:32 $begingroup$ the Eclipse microcontroller setup will be a good. But it's worth noting that Atmel studio uses avr-gcc and arm-none-eabi-gcc (and presumably an avr32 gcc) to do the actual compilation, all of which are available for other platforms. As are downloading tools for their bootloaders, and ISP and SWD/JTAG tools like avrdude, OpenOCD, etc.
3.19.6 AVR Options
These options are defined for AVR implementations:
-mmcu=mcu
Specify Atmel AVR instruction set architectures (ISA) or MCU type.
The default for this option is ‘avr2’.
GCC supports the following AVR devices and ISAs:
avr2
“Classic” devices with up to 8 KiB of program memory.
mcu = attiny22
, attiny26
, at90s2313
, at90s2323
, at90s2333
, at90s2343
, at90s4414
, at90s4433
, at90s4434
, at90c8534
, at90s8515
, at90s8535
.
avr25
“Classic” devices with up to 8 KiB of program memory and with the MOVW
instruction.
mcu = attiny13
, attiny13a
, attiny24
, attiny24a
, attiny25
, attiny261
, attiny261a
, attiny2313
, attiny2313a
, attiny43u
, attiny44
, attiny44a
, attiny45
, attiny48
, attiny441
, attiny461
, attiny461a
, attiny4313
, attiny84
, attiny84a
, attiny85
, attiny87
, attiny88
, attiny828
, attiny841
, attiny861
, attiny861a
, ata5272
, ata6616c
, at86rf401
.
avr3
“Classic” devices with 16 KiB up to 64 KiB of program memory.
mcu = at76c711
, at43usb355
.
avr31
“Classic” devices with 128 KiB of program memory.
mcu = atmega103
, at43usb320
.
avr35
“Classic” devices with 16 KiB up to 64 KiB of program memory and with the MOVW
instruction.
mcu = attiny167
, attiny1634
, atmega8u2
, atmega16u2
, atmega32u2
, ata5505
, ata6617c
, ata664251
, at90usb82
, at90usb162
.
avr4
“Enhanced” devices with up to 8 KiB of program memory.
mcu = atmega48
, atmega48a
, atmega48p
, atmega48pa
, atmega48pb
, atmega8
, atmega8a
, atmega8hva
, atmega88
, atmega88a
, atmega88p
, atmega88pa
, atmega88pb
, atmega8515
, atmega8535
, ata6285
, ata6286
, ata6289
, ata6612c
, at90pwm1
, at90pwm2
, at90pwm2b
, at90pwm3
, at90pwm3b
, at90pwm81
.
avr5
“Enhanced” devices with 16 KiB up to 64 KiB of program memory.
mcu = atmega16
, atmega16a
, atmega16hva
, atmega16hva2
, atmega16hvb
, atmega16hvbrevb
, atmega16m1
, atmega16u4
, atmega161
, atmega162
, atmega163
, atmega164a
, atmega164p
, atmega164pa
, atmega165
, atmega165a
, atmega165p
, atmega165pa
, atmega168
, atmega168a
, atmega168p
, atmega168pa
, atmega168pb
, atmega169
, atmega169a
, atmega169p
, atmega169pa
, atmega32
, atmega32a
, atmega32c1
, atmega32hvb
, atmega32hvbrevb
, atmega32m1
, atmega32u4
, atmega32u6
, atmega323
, atmega324a
, atmega324p
, atmega324pa
, atmega325
, atmega325a
, atmega325p
, atmega325pa
, atmega328
, atmega328p
, atmega328pb
, atmega329
, atmega329a
, atmega329p
, atmega329pa
, atmega3250
, atmega3250a
, atmega3250p
, atmega3250pa
, atmega3290
, atmega3290a
, atmega3290p
, atmega3290pa
, atmega406
, atmega64
, atmega64a
, atmega64c1
, atmega64hve
, atmega64hve2
, atmega64m1
, atmega64rfr2
, atmega640
, atmega644
, atmega644a
, atmega644p
, atmega644pa
, atmega644rfr2
, atmega645
, atmega645a
, atmega645p
, atmega649
, atmega649a
, atmega649p
, atmega6450
, atmega6450a
, atmega6450p
, atmega6490
, atmega6490a
, atmega6490p
, ata5795
, ata5790
, ata5790n
, ata5791
, ata6613c
, ata6614q
, ata5782
, ata5831
, ata8210
, ata8510
, ata5702m322
, at90pwm161
, at90pwm216
, at90pwm316
, at90can32
, at90can64
, at90scr100
, at90usb646
, at90usb647
, at94k
, m3000
.
avr51
“Enhanced” devices with 128 KiB of program memory.
mcu = atmega128
, atmega128a
, atmega128rfa1
, atmega128rfr2
, atmega1280
, atmega1281
, atmega1284
, atmega1284p
, atmega1284rfr2
, at90can128
, at90usb1286
, at90usb1287
.
avr6
“Enhanced” devices with 3-byte PC, i.e. with more than 128 KiB of program memory.
mcu = atmega256rfr2
, atmega2560
, atmega2561
, atmega2564rfr2
.
avrxmega2
“XMEGA” devices with more than 8 KiB and up to 64 KiB of program memory.
mcu = atxmega8e5
, atxmega16a4
, atxmega16a4u
, atxmega16c4
, atxmega16d4
, atxmega16e5
, atxmega32a4
, atxmega32a4u
, atxmega32c3
, atxmega32c4
, atxmega32d3
, atxmega32d4
, atxmega32e5
.
avrxmega3
“XMEGA” devices with up to 64 KiB of combined program memory and RAM, and with program memory visible in the RAM address space.
mcu = attiny202
, attiny204
, attiny212
, attiny214
, attiny402
, attiny404
, attiny406
, attiny412
, attiny414
, attiny416
, attiny417
, attiny804
, attiny806
, attiny807
, attiny814
, attiny816
, attiny817
, attiny1604
, attiny1606
, attiny1607
, attiny1614
, attiny1616
, attiny1617
, attiny3214
, attiny3216
, attiny3217
, atmega808
, atmega809
, atmega1608
, atmega1609
, atmega3208
, atmega3209
, atmega4808
, atmega4809
.
avrxmega4
“XMEGA” devices with more than 64 KiB and up to 128 KiB of program memory.
mcu = atxmega64a3
, atxmega64a3u
, atxmega64a4u
, atxmega64b1
, atxmega64b3
, atxmega64c3
, atxmega64d3
, atxmega64d4
.
avrxmega5
“XMEGA” devices with more than 64 KiB and up to 128 KiB of program memory and more than 64 KiB of RAM.
mcu = atxmega64a1
, atxmega64a1u
.
avrxmega6
“XMEGA” devices with more than 128 KiB of program memory.
mcu = atxmega128a3
, atxmega128a3u
, atxmega128b1
, atxmega128b3
, atxmega128c3
, atxmega128d3
, atxmega128d4
, atxmega192a3
, atxmega192a3u
, atxmega192c3
, atxmega192d3
, atxmega256a3
, atxmega256a3b
, atxmega256a3bu
, atxmega256a3u
, atxmega256c3
, atxmega256d3
, atxmega384c3
, atxmega384d3
.
avrxmega7
“XMEGA” devices with more than 128 KiB of program memory and more than 64 KiB of RAM.
mcu = atxmega128a1
, atxmega128a1u
, atxmega128a4u
.
avrtiny
“TINY” Tiny core devices with 512 B up to 4 KiB of program memory.
mcu = attiny4
, attiny5
, attiny9
, attiny10
, attiny20
, attiny40
.
avr1
This ISA is implemented by the minimal AVR core and supported for assembler only.
mcu = attiny11
, attiny12
, attiny15
, attiny28
, at90s1200
.
-mabsdata
Assume that all data in static storage can be accessed by LDS / STSinstructions. This option has only an effect on reduced Tiny devices likeATtiny40. See also the absdata
variable attribute.
-maccumulate-args
Accumulate outgoing function arguments and acquire/release the neededstack space for outgoing function arguments once in functionprologue/epilogue. Without this option, outgoing arguments are pushedbefore calling a function and popped afterwards.
Popping the arguments after the function call can be expensive onAVR so that accumulating the stack space might lead to smallerexecutables because arguments need not be removed from thestack after such a function call.
This option can lead to reduced code size for functions that performseveral calls to functions that get their arguments on the stack likecalls to printf-like functions.
-mbranch-cost=cost
Set the branch costs for conditional branch instructions tocost. Reasonable values for cost are small, non-negativeintegers. The default branch cost is 0.
-mcall-prologues
Functions prologues/epilogues are expanded as calls to appropriatesubroutines. Code size is smaller.
-mdouble=bits
-mlong-double=bits
Set the size (in bits) of the double
or long double
type,respectively. Possible values for bits are 32 and 64.Whether or not a specific value for bits is allowed depends onthe --with-double=
and --with-long-double=
configure options,and the same applies for the default values of the options.
-mgas-isr-prologues
Interrupt service routines (ISRs) may use the __gcc_isr
pseudoinstruction supported by GNU Binutils.If this option is on, the feature can still be disabled for individualISRs by means of the no_gccisr
function attribute. This feature is activated per defaultif optimization is on (but not with -Og, see Optimize Options),and if GNU Binutils support PR21683.
Avr-gcc Assembler Macro
-mint8
Assume int
to be 8-bit integer. This affects the sizes of all types: achar
is 1 byte, an int
is 1 byte, a long
is 2 bytes,and long long
is 4 bytes. Please note that this option does notconform to the C standards, but it results in smaller codesize.
-mmain-is-OS_task
Do not save registers in main
. The effect is the same likeattaching attribute OS_task
to main
. It is activated per default if optimization is on.
-mn-flash=num
Assume that the flash memory has a size of num times 64 KiB.
-mno-interrupts
Generated code is not compatible with hardware interrupts.Code size is smaller.
-mrelax
Try to replace CALL
resp. JMP
instruction by the shorterRCALL
resp. RJMP
instruction if applicable.Setting -mrelax just adds the --mlink-relax option tothe assembler’s command line and the --relax option to thelinker’s command line.
Jump relaxing is performed by the linker because jump offsets are notknown before code is located. Therefore, the assembler code generated by thecompiler is the same, but the instructions in the executable maydiffer from instructions in the assembler code.
Relaxing must be turned on if linker stubs are needed, see thesection on EIND
and linker stubs below.
-mrmw
Assume that the device supports the Read-Modify-Writeinstructions XCH
, LAC
, LAS
and LAT
.
-mshort-calls
Assume that RJMP
and RCALL
can target the wholeprogram memory.
This option is used internally for multilib selection. It isnot an optimization option, and you don’t need to set it by hand.
-msp8
Treat the stack pointer register as an 8-bit register,i.e. assume the high byte of the stack pointer is zero.In general, you don’t need to set this option by hand.
This option is used internally by the compiler to select andbuild multilibs for architectures avr2
and avr25
.These architectures mix devices with and without SPH
.For any setting other than -mmcu=avr2 or -mmcu=avr25the compiler driver adds or removes this option from the compilerproper’s command line, because the compiler then knows if the deviceor architecture has an 8-bit stack pointer and thus no SPH
register or not.
-mstrict-X
Use address register X
in a way proposed by the hardware. This meansthat X
is only used in indirect, post-increment orpre-decrement addressing.
Without this option, the X
register may be used in the same wayas Y
or Z
which then is emulated by additionalinstructions. For example, loading a value with X+const
addressing with asmall non-negative const < 64
to a register Rn isperformed as
-mtiny-stack
Only change the lower 8 bits of the stack pointer.
-mfract-convert-truncate
Allow to use truncation instead of rounding towards zero for fractional fixed-point types.
-nodevicelib
Don’t link against AVR-LibC’s device specific library lib<mcu>.a
.
-nodevicespecs
Don’t add -specs=device-specs/specs-mcu to the compiler driver’scommand line. The user takes responsibility for supplying the sub-processeslike compiler proper, assembler and linker with appropriate command lineoptions. This means that the user has to supply her private device specsfile by means of -specs=path-to-specs-file. There is nomore need for option -mmcu=mcu.
This option can also serve as a replacement for the older way ofspecifying custom device-specs files that needed -B some-path to point to a directorywhich contains a folder named device-specs
which contains a specs file namedspecs-mcu
, where mcu was specified by -mmcu=mcu.
-Waddr-space-convert
Warn about conversions between address spaces in the case where theresulting address space is not contained in the incoming address space.
-Wmisspelled-isr
Warn if the ISR is misspelled, i.e. without __vector prefix.Enabled by default.
3.19.6.1 EIND
and Devices with More Than 128 Ki Bytes of Flash
Pointers in the implementation are 16 bits wide.The address of a function or label is represented as word address sothat indirect jumps and calls can target any code address in therange of 64 Ki words.
In order to facilitate indirect jump on devices with more than 128 Kibytes of program memory space, there is a special function register calledEIND
that serves as most significant part of the target addresswhen EICALL
or EIJMP
instructions are used.
Indirect jumps and calls on these devices are handled as follows bythe compiler and are subject to some limitations:
- The compiler never sets
EIND
. - The compiler uses
EIND
implicitly inEICALL
/EIJMP
instructions or might readEIND
directly in order to emulate anindirect call/jump by means of aRET
instruction. - The compiler assumes that
EIND
never changes during the startupcode or during the application. In particular,EIND
is notsaved/restored in function or interrupt service routineprologue/epilogue. - For indirect calls to functions and computed goto, the linkergenerates stubs. Stubs are jump pads sometimes also calledtrampolines. Thus, the indirect call/jump jumps to such a stub.The stub contains a direct jump to the desired address.
- Linker relaxation must be turned on so that the linker generatesthe stubs correctly in all situations. See the compiler option-mrelax and the linker option --relax.There are corner cases where the linker is supposed to generate stubsbut aborts without relaxation and without a helpful error message.
- The default linker script is arranged for code with
EIND = 0
.If code is supposed to work for a setup withEIND != 0
, a customlinker script has to be used in order to place the sections whosename start with.trampolines
into the segment whereEIND
points to. - The startup code from libgcc never sets
EIND
.Notice that startup code is a blend of code from libgcc and AVR-LibC.For the impact of AVR-LibC onEIND
, see theAVR-LibC user manual. - It is legitimate for user-specific startup code to set up
EIND
early, for example by means of initialization code located insection.init3
. Such code runs prior to general startup codethat initializes RAM and calls constructors, but after the bitof startup code from AVR-LibC that setsEIND
to the segmentwhere the vector table is located.The
__trampolines_start
symbol is defined in the linker script. - Stubs are generated automatically by the linker ifthe following two conditions are met:
- - The address of a label is taken by means of the
gs
modifier(short for generate stubs) like so: - - The final location of that label is in a code segmentoutside the segment where the stubs are located.
- - The address of a label is taken by means of the
- The compiler emits such
gs
modifiers for code labels in thefollowing situations:- - Taking address of a function or code label.
- - Computed goto.
- - If prologue-save function is used, see -mcall-prologuescommand-line option.
- - Switch/case dispatch tables. If you do not want such dispatchtables you can specify the -fno-jump-tables command-line option.
- - C and C++ constructors/destructors called during startup/shutdown.
- - If the tools hit a
gs()
modifier explained above.
- Jumping to non-symbolic addresses like so is not supported:
Instead, a stub has to be set up, i.e. the function has to be calledthrough a symbol (
func_4
in the example):and the application be linked with -Wl,--defsym,func_4=0x4.Alternatively,
func_4
can be defined in the linker script.
3.19.6.2 Handling of the RAMPD
, RAMPX
, RAMPY
and RAMPZ
Special Function Registers
Some AVR devices support memories larger than the 64 KiB rangethat can be accessed with 16-bit pointers. To access memory locationsoutside this 64 KiB range, the content of a RAMP
register is used as high part of the address:The X
, Y
, Z
address register is concatenatedwith the RAMPX
, RAMPY
, RAMPZ
special functionregister, respectively, to get a wide address. Similarly,RAMPD
is used together with direct addressing.
- The startup code initializes the
RAMP
special functionregisters with zero. - If a named address space other thangeneric or
__flash
is used, thenRAMPZ
is setas needed before the operation. - If the device supports RAM larger than 64 KiB and the compilerneeds to change
RAMPZ
to accomplish an operation,RAMPZ
is reset to zero after the operation. - If the device comes with a specific
RAMP
register, the ISRprologue/epilogue saves/restores that SFR and initializes it withzero in case the ISR code might (implicitly) use it. - RAM larger than 64 KiB is not supported by GCC for AVR targets.If you use inline assembler to read from locations outside the16-bit address range and change one of the
RAMP
registers,you must reset it to zero after the access.
3.19.6.3 AVR Built-in Macros
Avr Gcc For Mac Os
GCC defines several built-in macros so that the user code can testfor the presence or absence of features. Almost any of the followingbuilt-in macros are deduced from device capabilities and thustriggered by the -mmcu= command-line option.
For even more AVR-specific built-in macros seeAVR Named Address Spaces and AVR Built-in Functions.
__AVR_ARCH__
Build-in macro that resolves to a decimal number that identifies thearchitecture and depends on the -mmcu=mcu option.Possible values are:
2
, 25
, 3
, 31
, 35
,4
, 5
, 51
, 6
for mcu=avr2
, avr25
, avr3
, avr31
,avr35
, avr4
, avr5
, avr51
, avr6
,
respectively and
100
,102
, 103
, 104
,105
, 106
, 107
for mcu=avrtiny
,avrxmega2
, avrxmega3
, avrxmega4
,avrxmega5
, avrxmega6
, avrxmega7
, respectively.If mcu specifies a device, this built-in macro is setaccordingly. For example, with -mmcu=atmega8 the macro isdefined to 4
.
__AVR_Device__
Setting -mmcu=device defines this built-in macro which reflectsthe device’s name. For example, -mmcu=atmega8 defines thebuilt-in macro __AVR_ATmega8__
, -mmcu=attiny261a defines__AVR_ATtiny261A__
, etc.
The built-in macros’ names followthe scheme __AVR_Device__
where Device isthe device name as from the AVR user manual. The difference betweenDevice in the built-in macro and device in-mmcu=device is that the latter is always lowercase.
If device is not a device but only a core architecture like‘avr51’, this macro is not defined.
__AVR_DEVICE_NAME__
Setting -mmcu=device defines this built-in macro tothe device’s name. For example, with -mmcu=atmega8 the macrois defined to atmega8
.
If device is not a device but only a core architecture like‘avr51’, this macro is not defined.
__AVR_XMEGA__
The device / architecture belongs to the XMEGA family of devices.
__AVR_HAVE_ELPM__
The device has the ELPM
instruction.
__AVR_HAVE_ELPMX__
The device has the ELPM Rn,Z
and ELPMRn,Z+
instructions.
__AVR_HAVE_MOVW__
The device has the MOVW
instruction to perform 16-bitregister-register moves.
__AVR_HAVE_LPMX__
The device has the LPM Rn,Z
andLPM Rn,Z+
instructions.
__AVR_HAVE_MUL__
The device has a hardware multiplier.
__AVR_HAVE_JMP_CALL__
The device has the JMP
and CALL
instructions.This is the case for devices with more than 8 KiB of programmemory.
__AVR_HAVE_EIJMP_EICALL__
__AVR_3_BYTE_PC__
The device has the EIJMP
and EICALL
instructions.This is the case for devices with more than 128 KiB of program memory.This also means that the program counter(PC) is 3 bytes wide.
__AVR_2_BYTE_PC__
The program counter (PC) is 2 bytes wide. This is the case for deviceswith up to 128 KiB of program memory.
__AVR_HAVE_8BIT_SP__
__AVR_HAVE_16BIT_SP__
The stack pointer (SP) register is treated as 8-bit respectively16-bit register by the compiler.The definition of these macros is affected by -mtiny-stack.
__AVR_HAVE_SPH__
__AVR_SP8__
The device has the SPH (high part of stack pointer) special functionregister or has an 8-bit stack pointer, respectively.The definition of these macros is affected by -mmcu= andin the cases of -mmcu=avr2 and -mmcu=avr25 alsoby -msp8.
__AVR_HAVE_RAMPD__
__AVR_HAVE_RAMPX__
__AVR_HAVE_RAMPY__
__AVR_HAVE_RAMPZ__
The device has the RAMPD
, RAMPX
, RAMPY
,RAMPZ
special function register, respectively.
__NO_INTERRUPTS__
This macro reflects the -mno-interrupts command-line option.
__AVR_ERRATA_SKIP__
__AVR_ERRATA_SKIP_JMP_CALL__
Some AVR devices (AT90S8515, ATmega103) must not skip 32-bitinstructions because of a hardware erratum. Skip instructions areSBRS
, SBRC
, SBIS
, SBIC
and CPSE
.The second macro is only defined if __AVR_HAVE_JMP_CALL__
is alsoset.
__AVR_ISA_RMW__
The device has Read-Modify-Write instructions (XCH, LAC, LAS and LAT).
__AVR_SFR_OFFSET__=offset
Instructions that can address I/O special function registers directlylike IN
, OUT
, SBI
, etc. may use a differentaddress as if addressed by an instruction to access RAM like LD
or STS
. This offset depends on the device architecture and hasto be subtracted from the RAM address in order to get therespective I/O address.
__AVR_SHORT_CALLS__
The -mshort-calls command line option is set.
__AVR_PM_BASE_ADDRESS__=addr
Some devices support reading from flash memory by means of LD*
instructions. The flash memory is seen in the data address spaceat an offset of __AVR_PM_BASE_ADDRESS__
. If this macrois not defined, this feature is not available. If defined,the address space is linear and there is no need to put.rodata
into RAM. This is handled by the default linkerdescription file, and is currently available foravrtiny
and avrxmega3
. Even more convenient,there is no need to use address spaces like __flash
orfeatures like attribute progmem
and pgm_read_*
.
__WITH_AVRLIBC__
The compiler is configured to be used together with AVR-Libc.See the --with-avrlibc configure option.
__HAVE_DOUBLE_MULTILIB__
Defined if -mdouble= acts as a multilib option.
__HAVE_DOUBLE32__
__HAVE_DOUBLE64__
Defined if the compiler supports 32-bit double resp. 64-bit double.The actual layout is specified by option -mdouble=.
__DEFAULT_DOUBLE__
The size in bits of double
if -mdouble= is not set.To test the layout of double
in a program, use the built-inmacro __SIZEOF_DOUBLE__
.
__HAVE_LONG_DOUBLE32__
__HAVE_LONG_DOUBLE64__
__HAVE_LONG_DOUBLE_MULTILIB__
__DEFAULT_LONG_DOUBLE__
Same as above, but for long double
instead of double
.
__WITH_DOUBLE_COMPARISON__
Reflects the --with-double-comparison={tristate|bool|libf7}
configure optionand is defined to 2
or 3
.
__WITH_LIBF7_LIBGCC__
__WITH_LIBF7_MATH__
__WITH_LIBF7_MATH_SYMBOLS__
Reflects the --with-libf7={libgcc|math|math-symbols}
configure option.
Next: Blackfin Options, Previous: ARM Options, Up: Submodel Options [Contents][Index]
Avr Gcc For Mac Download
Hello,
I've been programming on Arduino for sometime, and now I am starting to learn how to program the ATmega328 using AVR-C and an AVR programmer..
unfortunately it seems the process is a bit more complicated on mac (I am currently using OS X El capitan version 10.11.6) since there's no Atmel studio on mac.
Avr-gcc Predefined Macros
I've found some resources online but it seems many of them are outdated.
so my question is, is anyone here doing AVR programming on mac? and I'd really appreciate it if anyone can provide me with links for the tools I need (IDE, etc..) so I can start writing C code and upload them to the ATMega through the USB AVR programmer that I have.
Thanks,