[avr-gcc-list] sample Hello World program using AVR-GCC

[Larsen, Morten ActeNO]

Hmmm, looks as if I actually *do* have some 
problems asociated w. my attachments.
So, in order to get it right - 
I hereby include them in the message text!

Cut&Paste code and Makefile to appropriate 
places, and type 'make extcoff' or simply 'make'
(the former if you want to debug within AVRStudio4.08+)
Good luck!

-----------(snip)-------------------------

/*
 "stdio_eks1.c"
 -------------
 Example of using redirction of stdio to UART
 via AVR-LibC stdc library for structured I/O.
 Written for ATmega16 on a STK500 board;
 connect switch "SW0" to pin <PD2>(="INT0"),
 and <PD0>-->"RxD" plus <PD1>-->"TxD".
 Then plug your PC's serialport to "RS232 Spare" 
 DSUB-connector and start terminal emulator program etc.
*/

#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/signal.h>
#include <avr/pgmspace.h>

#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>

/* Run the UART at 9600 baud  */
#define BAUD9600  25 /* @4MHz internal RC-osc. */

/* lowlevel driver routine */
int uart_putchar(unsigned char c)
{
   if (c == '\n') 
     // make <CR> understandable also on UNIX-systems :-)
     c = '\r';    
   loop_until_bit_is_set(UCSRA, UDRE);
   UDR = c;
   return 0;
}
  
/* ISR for INT0 - triggered by posedge event on PD2 */
SIGNAL(SIG_INTERRUPT0)
{
   printf("INT0-event (positive edge) has taken place!\n");
   GIFR = 0x00;
}   
   

int main() 
{
  int i, j, k;
  int bps;
  
  cli();
  
  /* enable UART */
  cbi(UCSRC, UMSEL);   // mode=asynkron (is default after Reset)
  cbi(UCSRA, U2X);     // no 2x-clocking (is also default)
  // 
  bps = BAUD9600;
  UBRRH = (unsigned char)(bps>>8);
  UBRRL = (unsigned char)bps;
  sbi(UCSRB, TXEN);
  /* rest is OK - default setting is 8N1-format */
  
  /* primitive test of 'uart_putchar' */
  uart_putchar('H');
  uart_putchar('e');
  uart_putchar('i');
  uart_putchar('\n');
  
  /* initializing STDOUT, possibly also STDERR=STDOUT */
  stdout = fdevopen((FILE *)uart_putchar, NULL, 0);
  
  printf("baud rate register UBRR for 9600 baud = %u\n", bps);
  
  /* enable extern interrupts INT0 */
  sbi(MCUCR, ISC00);
  sbi(MCUCR, ISC01);   // ISC[1:0]="11" -> _|- (posedge)triggered 
  sbi(GIMSK, INT0);    // enable INT0
  GIFR = 0x00;         // clear of all INT<n> flags
                       // to accept new INT-events
                       
  sei();  // wait for INTs ...
  
  while (1) {
    for (i=0;i<10000;i++) {
       for (j=0;j<1000;j++) {
          for (k=0;k<100;k++) {
             printf("InnerLoop-iterasjon number %d\n", k);
          }
       }
    }
  }   
  return 0;
}

-----------(snip)-------------------------

# WinAVR Sample makefile written by Eric B. Weddington, Jörg Wunsch, et al.
# Released to the Public Domain
# Please read the make user manual!
#
#
# On command line:
#
# make all = Make software.
#
# make clean = Clean out built project files.
#
# make coff = Convert ELF to AVR COFF (for use with AVR Studio 3.x or
VMLAB).
#
# make extcoff = Convert ELF to AVR Extended COFF (for use with AVR Studio
#                4.07 or greater).
#
# make program = Download the hex file to the device, using avrdude.  Please
#                customize the avrdude settings below first!
#
# make filename.s = Just compile filename.c into the assembler code only
#
# To rebuild project do "make clean" then "make all".
#


# MCU name
MCU = atmega16

# Output format. (can be srec, ihex, binary)
FORMAT = ihex

# Target file name (without extension).
TARGET = stdio_eks

# Optimization level, can be [0, 1, 2, 3, s]. 0 turns off optimization.
# (Note: 3 is not always the best optimization level. See avr-libc FAQ.)
OPT = s


# List C source files here. (C dependencies are automatically generated.)
SRC = $(TARGET).c

# If there is more than one source file, append them above, or adjust and
# uncomment the following:
#SRC += foo.c bar.c

# You can also wrap lines by appending a backslash to the end of the line:
#SRC += baz.c \
#xyzzy.c



# List Assembler source files here.
# Make them always end in a capital .S.  Files ending in a lowercase .s
# will not be considered source files but generated files (assembler
# output from the compiler), and will be deleted upon "make clean"!
# Even though the DOS/Win* filesystem matches both .s and .S the same,
# it will preserve the spelling of the filenames, and gcc itself does
# care about how the name is spelled on its command-line.
ASRC = 




# Optional compiler flags.
#  -g:        generate debugging information (for GDB, or for COFF
conversion)
#  -O*:       optimization level
#  -f...:     tuning, see gcc manual and avr-libc documentation
#  -Wall...:  warning level
#  -Wa,...:   tell GCC to pass this to the assembler.
#    -ahlms:  create assembler listing
CFLAGS = -g -O$(OPT) \
        -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums \
        -Wall -Wstrict-prototypes \
        -Wa,-ahlms=$(<:.c=.lst)



# Optional assembler flags.
#  -Wa,...:   tell GCC to pass this to the assembler.
#  -ahlms:    create listing
#  -gstabs:   have the assembler create line number information; note that
#             for use in COFF files, additional information about filenames
#             and function names needs to be present in the assembler source
#             files -- see avr-libc docs [FIXME: not yet described there]
ASFLAGS = -Wa,-ahlms=$(<:.S=.lst),-gstabs 



# Optional linker flags.
#  -Wl,...:   tell GCC to pass this to linker.
#  -Map:      create map file
#  --cref:    add cross reference to  map file
LDFLAGS = -Wl,-Map=$(TARGET).map,--cref



# Additional libraries
#
# Minimalistic printf version
LDFLAGS += -Wl,-u,vfprintf -lprintf_min
#
# Floating point printf version (requires -lm below)
#LDFLAGS +=  -Wl,-u,vfprintf -lprintf_flt
#
# -lm = math library
#LDFLAGS += -lm

#
---------------------------------------------------------------------------

# Define directories, if needed.
DIRAVR = c:/avr/avrgcc
DIRAVRBIN = $(DIRAVR)/bin
DIRAVRUTILS = $(DIRAVR)/utils/bin
DIRINC = .
DIRLIB = $(DIRAVR)/avr/lib


# Define programs and commands.
SHELL = sh

CC = avr-gcc

OBJCOPY = avr-objcopy
OBJDUMP = avr-objdump
SIZE = avr-size


# Programming support using avrdude.
AVRDUDE = avrdude


REMOVE = rm -f
COPY = cp

HEXSIZE = $(SIZE) --target=$(FORMAT) $(TARGET).hex
ELFSIZE = $(SIZE) -A $(TARGET).elf

FINISH = echo Errors: none
BEGIN = echo -------- begin --------
END = echo --------  end  --------




# Define all object files.
OBJ = $(SRC:.c=.o) $(ASRC:.S=.o) 

# Define all listing files.
LST = $(ASRC:.S=.lst) $(SRC:.c=.lst)

# Combine all necessary flags and optional flags.
# Add target processor to flags.
ALL_CFLAGS = -mmcu=$(MCU) -I. $(CFLAGS)
ALL_ASFLAGS = -mmcu=$(MCU) -I. -x assembler-with-cpp $(ASFLAGS)



# Default target.
all: begin gccversion sizebefore $(TARGET).elf $(TARGET).hex $(TARGET).eep \
        $(TARGET).lss sizeafter finished end


# Eye candy.
# AVR Studio 3.x does not check make's exit code but relies on
# the following magic strings to be generated by the compile job.
begin:
        @$(BEGIN)

finished:
        @$(FINISH)

end:
        @$(END)


# Display size of file.
sizebefore:
        @if [ -f $(TARGET).elf ]; then echo Size before:; $(ELFSIZE);fi

sizeafter:
        @if [ -f $(TARGET).elf ]; then echo Size after:; $(ELFSIZE);fi



# Display compiler version information.
gccversion : 
        $(CC) --version




# Convert ELF to COFF for use in debugging / simulating in
# AVR Studio or VMLAB.
COFFCONVERT=$(OBJCOPY) --debugging \
        --change-section-address .data-0x800000 \
        --change-section-address .bss-0x800000 \
        --change-section-address .noinit-0x800000 \
        --change-section-address .eeprom-0x810000 


coff: $(TARGET).elf
        $(COFFCONVERT) -O coff-avr $< $(TARGET).cof


extcoff: $(TARGET).elf
        $(COFFCONVERT) -O coff-ext-avr $< $(TARGET).cof




# Program the device.  The magic trickery below examines the .eep hex
# file whether the size is > 0, and if so, reprograms the EEPROM as
# well.  Just delete these lines if you don't want this feature (like
# on the ATmegas with the EESAVE fuse bit set).
program: $(TARGET).hex $(TARGET).eep
        $(AVRDUDE) $(AVRDUDE_FLAGS) $(AVRDUDE_ERASE)
        $(AVRDUDE) $(AVRDUDE_FLAGS) -i $(TARGET).hex
        @$(SIZE) --target=$(FORMAT) $(TARGET).eep | while read line; \
        do \
                set -- $$line; \
                if [ "x$$1" != "x0" ] ; then continue; fi; \
                if [ "$$2" -ne 0 ] ; then \
                        echo $(AVRDUDE) $(AVRDUDE_FLAGS) -m eeprom -i
$(TARGET).eep; \
                        $(AVRDUDE) $(AVRDUDE_FLAGS) -m eeprom -i
$(TARGET).eep; \
                        break; \
                fi; \
        done


# Create final output files (.hex, .eep) from ELF output file.
%.hex: %.elf
        $(OBJCOPY) -O $(FORMAT) -R .eeprom $< $@

%.eep: %.elf
        -$(OBJCOPY) -j .eeprom --set-section-flags=.eeprom="alloc,load" \
        --change-section-lma .eeprom=0 -O $(FORMAT) $< $@

# Create extended listing file from ELF output file.
%.lss: %.elf
        $(OBJDUMP) -h -S $< > $@



# Link: create ELF output file from object files.
.SECONDARY : $(TARGET).elf
.PRECIOUS : $(OBJ)
%.elf: $(OBJ)
        $(CC) $(ALL_CFLAGS) $(OBJ) --output $@ $(LDFLAGS)


# Compile: create object files from C source files.
%.o : %.c
        $(CC) -c $(ALL_CFLAGS) $< -o $@


# Compile: create assembler files from C source files.
%.s : %.c
        $(CC) -S $(ALL_CFLAGS) $< -o $@


# Assemble: create object files from assembler source files.
%.o : %.S
        $(CC) -c $(ALL_ASFLAGS) $< -o $@






# Target: clean project.
clean: begin clean_list finished end

clean_list :
        $(REMOVE) $(TARGET).hex
        $(REMOVE) $(TARGET).eep
        $(REMOVE) $(TARGET).obj
        $(REMOVE) $(TARGET).cof
        $(REMOVE) $(TARGET).elf
        $(REMOVE) $(TARGET).map
        $(REMOVE) $(TARGET).obj
        $(REMOVE) $(TARGET).a90
        $(REMOVE) $(TARGET).sym
        $(REMOVE) $(TARGET).lnk
        $(REMOVE) $(TARGET).lss
        $(REMOVE) $(OBJ)
        $(REMOVE) $(LST)
        $(REMOVE) $(SRC:.c=.s)
        $(REMOVE) $(SRC:.c=.d)


# Automatically generate C source code dependencies. 
# (Code originally taken from the GNU make user manual and modified 
# (See README.txt Credits).)
#
# Note that this will work with sh (bash) and sed that is shipped with
WinAVR
# (see the SHELL variable defined above).
# This may not work with other shells or other seds.
#
%.d: %.c
        set -e; $(CC) -MM $(ALL_CFLAGS) $< \
        | sed 's,\(.*\)\.o[ :]*,\1.o \1.d : ,g' > $@; \
        [ -s $@ ] || rm -f $@


# Remove the '-' if you want to see the dependency files generated.
-include $(SRC:.c=.d)



# Listing of phony targets.
.PHONY : all begin finish end sizebefore sizeafter gccversion coff extcoff \
        clean clean_list program


------------------------------------------

Se my example attached and associated 
makefile (WinAVR 'standard' sample modified)!
"makefile.cof" outputs extended COFF which 
works pretty well with AVRStudio4.08 (at least for me)
using JTAGICE f.ex.

PS: example is written for ATmega16 - 
may easily be modified to suit any ATmega.
(I believe some comments are in Norwegian, sorry ...)

PS,PS: I do not actually print out "Hello World" here ...;-)

Rgds:
Morten Larsen


> -----Original Message-----
> From: David Morrison [mailto:address@hidden
> Sent: Tuesday, January 20, 2004 5:08 AM
> To: address@hidden
> Subject: [avr-gcc-list] sample hello world! program using GCC
> 
> 
> Hi all,
> I am a complete newbie to embedded programming the AVR and 
> have purchased a CANDIP which has a mega162 MCU to learn on.  
> I was wondering if someone could send me a simple hello world 
> program (written using GCC), so I could see how to initialize 
> the serial port and get the printf redirected to it.  Sorry 
> if this seems like a RTFM question but I have looked at the 
> docs and am still confused!
>  
> Thanks for the help,
> Dave
> address@hidden
> 
> 
> 
> I have always wished that my computer would be as easy to use 
> as my telephone. My wish has come true. I no longer know how 
> to use my telephone.
>       -Bjarne Stroustrup, computer science professor, designer of C++
>        programming language (1950- )
> _______________________________________________
> avr-gcc-list mailing list
> address@hidden
> http://www.avr1.org/mailman/listinfo/avr-gcc-list
>