Commit 990cdad4 authored by Dave Griffiths's avatar Dave Griffiths

added atmega code

parent 517eafa5
I2C_slave.o: I2C_slave.c /usr/lib/avr/include/avr/io.h \
/usr/lib/avr/include/avr/sfr_defs.h /usr/lib/avr/include/inttypes.h \
/usr/lib/gcc/avr/4.8.2/include/stdint.h /usr/lib/avr/include/stdint.h \
/usr/lib/avr/include/avr/iom328p.h /usr/lib/avr/include/avr/portpins.h \
/usr/lib/avr/include/avr/common.h /usr/lib/avr/include/avr/version.h \
/usr/lib/avr/include/avr/fuse.h /usr/lib/avr/include/avr/lock.h \
/usr/lib/avr/include/util/twi.h /usr/lib/avr/include/avr/interrupt.h \
main.o: main.c /usr/lib/avr/include/avr/io.h \
/usr/lib/avr/include/avr/sfr_defs.h /usr/lib/avr/include/inttypes.h \
/usr/lib/gcc/avr/4.8.2/include/stdint.h /usr/lib/avr/include/stdint.h \
/usr/lib/avr/include/avr/iom328p.h /usr/lib/avr/include/avr/portpins.h \
/usr/lib/avr/include/avr/common.h /usr/lib/avr/include/avr/version.h \
/usr/lib/avr/include/avr/fuse.h /usr/lib/avr/include/avr/lock.h \
/usr/lib/avr/include/util/delay.h \
/usr/lib/avr/include/util/delay_basic.h /usr/lib/avr/include/math.h \
/usr/lib/avr/include/stdlib.h /usr/lib/gcc/avr/4.8.2/include/stddef.h \
/usr/lib/avr/include/avr/interrupt.h I2C_slave.h
#include <avr/io.h>
#include <util/twi.h>
#include <avr/interrupt.h>
#include "I2C_slave.h"
void I2C_init(uint8_t address){
// load address into TWI address register
TWAR = address;
// set the TWCR to enable address matching and enable TWI, clear TWINT, enable TWI interrupt
TWCR = (1<<TWIE) | (1<<TWEA) | (1<<TWINT) | (1<<TWEN);
void I2C_stop(void){
// clear acknowledge and enable bits
TWCR &= ~( (1<<TWEA) | (1<<TWEN) );
// temporary stores the received data
uint8_t data;
// own address has been acknowledged
if( (TWSR & 0xF8) == TW_SR_SLA_ACK ){
buffer_address = 0xFF;
// clear TWI interrupt flag, prepare to receive next byte and acknowledge
TWCR |= (1<<TWIE) | (1<<TWINT) | (1<<TWEA) | (1<<TWEN);
else if( (TWSR & 0xF8) == TW_SR_DATA_ACK ){ // data has been received in slave receiver mode
// save the received byte inside data
data = TWDR;
// check wether an address has already been transmitted or not
if(buffer_address == 0xFF){
buffer_address = data;
// clear TWI interrupt flag, prepare to receive next byte and acknowledge
TWCR |= (1<<TWIE) | (1<<TWINT) | (1<<TWEA) | (1<<TWEN);
else{ // if a databyte has already been received
// store the data at the current address
rxbuffer[buffer_address] = data;
// increment the buffer address
// if there is still enough space inside the buffer
if(buffer_address < 0xFF){
// clear TWI interrupt flag, prepare to receive next byte and acknowledge
TWCR |= (1<<TWIE) | (1<<TWINT) | (1<<TWEA) | (1<<TWEN);
// clear TWI interrupt flag, prepare to receive last byte and don't acknowledge
TWCR |= (1<<TWIE) | (1<<TWINT) | (0<<TWEA) | (1<<TWEN);
else if( (TWSR & 0xF8) == TW_ST_DATA_ACK ){ // device has been addressed to be a transmitter
// copy data from TWDR to the temporary memory
data = TWDR;
// if no buffer read address has been sent yet
if( buffer_address == 0xFF ){
buffer_address = data;
// copy the specified buffer address into the TWDR register for transmission
TWDR = txbuffer[buffer_address];
// increment buffer read address
// if there is another buffer address that can be sent
if(buffer_address < 0xFF){
// clear TWI interrupt flag, prepare to send next byte and receive acknowledge
TWCR |= (1<<TWIE) | (1<<TWINT) | (1<<TWEA) | (1<<TWEN);
// clear TWI interrupt flag, prepare to send last byte and receive not acknowledge
TWCR |= (1<<TWIE) | (1<<TWINT) | (0<<TWEA) | (1<<TWEN);
// if none of the above apply prepare TWI to be addressed again
TWCR |= (1<<TWIE) | (1<<TWEA) | (1<<TWEN);
#ifndef I2C_SLAVE_H
#define I2C_SLAVE_H
volatile uint8_t buffer_address;
volatile uint8_t txbuffer[0xFF];
volatile uint8_t rxbuffer[0xFF];
void I2C_init(uint8_t address);
void I2C_stop(void);
#endif // I2C_SLAVE_H
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# MCU name
MCU = atmega328
# Main Oscillator Frequency
# This is only used to define F_OSC in all assembler and c-sources.
F_CPU = 16000000UL
# Output format. (can be srec, ihex, binary)
FORMAT = ihex
# Target file name (without extension).
TARGET = main
# List C source files here. (C dependencies are automatically generated.)
SRC = $(TARGET).c \
# List Assembler source files here.
# Make them always end in a capital .S. Files ending in a lowercase .s
# will not be considered source files but generated files (assembler
# output from the compiler), and will be deleted upon "make clean"!
# Even though the DOS/Win* filesystem matches both .s and .S the same,
# it will preserve the spelling of the filenames, and gcc itself does
# care about how the name is spelled on its command-line.
# Optimization level, can be [0, 1, 2, 3, s].
# 0 = turn off optimization. s = optimize for size.
# (Note: 3 is not always the best optimization level. See avr-libc FAQ.)
OPT = s
# Debugging format.
# Native formats for AVR-GCC's -g are stabs [default], or dwarf-2.
# AVR (extended) COFF requires stabs, plus an avr-objcopy run.
#DEBUG = stabs
DEBUG = dwarf-2
# List any extra directories to look for include files here.
# Each directory must be seperated by a space.
# Compiler flag to set the C Standard level.
# c89 - "ANSI" C
# gnu89 - c89 plus GCC extensions
# c99 - ISO C99 standard (not yet fully implemented)
# gnu99 - c99 plus GCC extensions
CSTANDARD = -std=gnu99
# Place -D or -U options here
# Place -I options here
# Compiler flags.
# -g*: generate debugging information
# -O*: optimization level
# -f...: tuning, see GCC manual and avr-libc documentation
# -Wall...: warning level
# -Wa,...: tell GCC to pass this to the assembler.
# -adhlns...: create assembler listing
CFLAGS += -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums
CFLAGS += -Wall -Wstrict-prototypes
CFLAGS += -Wa,-adhlns=$(<:.c=.lst)
CFLAGS += $(patsubst %,-I%,$(EXTRAINCDIRS))
# 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,-adhlns=$(<:.S=.lst),-gstabs
#Additional libraries.
# Minimalistic printf version
PRINTF_LIB_MIN = -Wl,-u,vfprintf -lprintf_min
# Floating point printf version (requires MATH_LIB = -lm below)
PRINTF_LIB_FLOAT = -Wl,-u,vfprintf -lprintf_flt
# Minimalistic scanf version
SCANF_LIB_MIN = -Wl,-u,vfscanf -lscanf_min
# Floating point + %[ scanf version (requires MATH_LIB = -lm below)
SCANF_LIB_FLOAT = -Wl,-u,vfscanf -lscanf_flt
MATH_LIB = -lm
# External memory options
# 64 KB of external RAM, starting after internal RAM (ATmega128!),
# used for variables (.data/.bss) and heap (malloc()).
#EXTMEMOPTS = -Wl,-Tdata=0x801100,--defsym=__heap_end=0x80ffff
# 64 KB of external RAM, starting after internal RAM (ATmega128!),
# only used for heap (malloc()).
#EXTMEMOPTS = -Wl,--defsym=__heap_start=0x801100,--defsym=__heap_end=0x80ffff
# Linker flags.
# -Wl,...: tell GCC to pass this to linker.
# -Map: create map file
# --cref: add cross reference to map file
LDFLAGS = -Wl,-Map=$(TARGET).map,--cref
# Programming support using avrdude. Settings and variables.
# Programming hardware: alf avr910 avrisp bascom bsd
# dt006 pavr picoweb pony-stk200 sp12 stk200 stk500
# Type: avrdude -c ?
# to get a full listing.
# com1 = serial port. Use lpt1 to connect to parallel port.
AVRDUDE_PORT = COM9 # programmer connected to serial device
# Uncomment the following if you want avrdude's erase cycle counter.
# Note that this counter needs to be initialized first using -Yn,
# see avrdude manual.
# Uncomment the following if you do /not/ wish a verification to be
# performed after programming the device.
# Increase verbosity level. Please use this when submitting bug
# reports about avrdude. See <>
# to submit bug reports.
# ---------------------------------------------------------------------------
# Define directories, if needed.
DIRAVR = c:/winavr
DIRLIB = $(DIRAVR)/avr/lib
# Define programs and commands.
SHELL = sh
CC = avr-gcc
OBJCOPY = avr-objcopy
OBJDUMP = avr-objdump
SIZE = avr-size
NM = avr-nm
AVRDUDE = avrdude
REMOVE = rm -f
COPY = cp
# Define Messages
# English
MSG_ERRORS_NONE = Errors: none
MSG_BEGIN = -------- begin --------
MSG_END = -------- end --------
MSG_SIZE_BEFORE = Size before:
MSG_SIZE_AFTER = Size after:
MSG_COFF = Converting to AVR COFF:
MSG_EXTENDED_COFF = Converting to AVR Extended COFF:
MSG_FLASH = Creating load file for Flash:
MSG_EEPROM = Creating load file for EEPROM:
MSG_EXTENDED_LISTING = Creating Extended Listing:
MSG_SYMBOL_TABLE = Creating Symbol Table:
MSG_LINKING = Linking:
MSG_COMPILING = Compiling:
MSG_ASSEMBLING = Assembling:
MSG_CLEANING = Cleaning project:
# Define all object files.
OBJ = $(SRC:.c=.o) $(ASRC:.S=.o)
# Define all listing files.
LST = $(ASRC:.S=.lst) $(SRC:.c=.lst)
# Compiler flags to generate dependency files.
### GENDEPFLAGS = -Wp,-M,-MP,-MT,$(*F).o,-MF,.dep/$(@F).d
GENDEPFLAGS = -MD -MP -MF .dep/$(@F).d
# Combine all necessary flags and optional flags.
# Add target processor to flags.
ALL_ASFLAGS = -mmcu=$(MCU) -I. -x assembler-with-cpp $(ASFLAGS)
# Default target.
all: begin gccversion sizebefore build sizeafter finished end
build: elf hex eep lss sym
elf: $(TARGET).elf
hex: $(TARGET).hex
eep: $(TARGET).eep
lss: $(TARGET).lss
sym: $(TARGET).sym
# 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.
@echo $(MSG_BEGIN)
@echo $(MSG_END)
# Display size of file.
HEXSIZE = $(SIZE) --target=$(FORMAT) $(TARGET).hex
@if [ -f $(TARGET).elf ]; then echo; echo $(MSG_SIZE_BEFORE); $(ELFSIZE); echo; fi
@if [ -f $(TARGET).elf ]; then echo; echo $(MSG_SIZE_AFTER); $(ELFSIZE); echo; fi
# Display compiler version information.
gccversion :
@$(CC) --version
# Program the device.
program: $(TARGET).hex $(TARGET).eep
# Convert ELF to COFF for use in debugging / simulating in AVR Studio or VMLAB.
COFFCONVERT=$(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
@echo $(MSG_COFF) $(TARGET).cof
$(COFFCONVERT) -O coff-avr $< $(TARGET).cof
extcoff: $(TARGET).elf
$(COFFCONVERT) -O coff-ext-avr $< $(TARGET).cof
# Create final output files (.hex, .eep) from ELF output file.
%.hex: %.elf
@echo $(MSG_FLASH) $@
$(OBJCOPY) -O $(FORMAT) -R .eeprom $< $@
%.eep: %.elf
@echo $(MSG_EEPROM) $@
-$(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 $< > $@
# Create a symbol table from ELF output file.
%.sym: %.elf
@echo $(MSG_SYMBOL_TABLE) $@
$(NM) -n $< > $@
# Link: create ELF output file from object files.
%.elf: $(OBJ)
@echo $(MSG_LINKING) $@
$(CC) $(ALL_CFLAGS) $(OBJ) --output $@ $(LDFLAGS)
# Compile: create object files from C source files.
%.o : %.c
@echo $(MSG_COMPILING) $<
$(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
@echo $(MSG_ASSEMBLING) $<
$(CC) -c $(ALL_ASFLAGS) $< -o $@
# Target: clean project.
clean: begin clean_list finished end
clean_list :
$(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
#ifndef F_CPU
#define F_CPU 16000000UL
#include <avr/io.h>
#include <util/delay.h>
#include <stdlib.h>
#include <avr/interrupt.h>
#include "I2C_slave.h"
// buffer used to convert integer to string
char buffer[3];
void set_led_state(u8 s)
if (s) PORTB|=_BV(LED);
else PORTB&=~_BV(LED);
void init_uart(uint16_t baudrate){
uint16_t UBRR_val = (F_CPU/16)/(baudrate-1);
UBRR0H = UBRR_val >> 8;
UBRR0L = UBRR_val;
UCSR0B |= (1<<TXEN0) | (1<<RXEN0) | (1<<RXCIE0); // UART TX (Transmit - senden) einschalten
UCSR0C |= (1<<USBS0) | (3<<UCSZ00); //Modus Asynchron 8N1 (8 Datenbits, No Parity, 1 Stopbit)
void uart_putc(unsigned char c){
while(!(UCSR0A & (1<<UDRE0))); // wait until sending is possible
UDR0 = c; // output character saved in c
void uart_puts(char *s){