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Bitmania
2011-04-22 10:04
by bitman
USB Thermometer



Ich hab schon länger nach einem USB Termometer gesucht das einfach nur die Temperatur eines Thermosensors auf einem USB-Serial-Interface ausgibt. Leider bin ich nirgends richtig fündig geworden.
Irgendwann hab ich dann mal einen DS1820 mitbestellt, der seitdem hier rumliegt.

Heute war es soweit und ich hab mich der Sache mal wieder angenommen.
Mit einem Atmega88 konnte ich den Sensor ansprechen und dann die Temperatur auf dem UART ausgeben, eine kleine Adapterplatine wandelt das Serielle ins USB-Protokoll.

Zum Ansprechen des Sensors habe ich dann ein sehr gutes Dokument gefunden (Author:Gerard Marull Paretas) welches ich gut in C mit avr-gcc umsetzen konnte:

Stückliste der benötigten Teile:
1x 100nF
2x 22pF
1x 16 MHz Quarz
1x 10k
1x 1k
1x LED 3mm grn
1x DS1820 (Temp Sensor)
1x Atmega88
1x FTDI Basic Breakout 5V  (Serial 2 USB Adapter)
diverse Sockel etc 

Mit dem Osziloskop habe ich mit einer kleinen Testschleife das Timing mit dem von mir verwendeten 16MHz Quarz überprüft.
 


Der Prototyp entstand erstmal auf dem Steckbrett, und wurde nachdem alles lief auf Lochraster übertragen:

 

Hier der fertige Prototyp:



Die Temperatur kann nun unter Linux sehr einfach ausgelesen und weiterverarbeitet werden:




Update: 2011-04-22:

Ich lade das auf dem Heimserver regelmäßig in eine RRD-Datenbank und bekomme eine schöne Kurve:





main.c
//------------------------------------------------------------------------------
// AVR-Temp Sensor
// bitman@bitmania.de
// www.bitmania.de
//------------------------------------------------------------------------------
// Based on the publication:
// Using DS18B20 digital temperature sensor on AVR microcontrollers
// Description and application, Version 1.0 (Preliminary)
// by Gerard Marull Paretas, September 2007
//------------------------------------------------------------------------------
// Fuses
// set 16MHz: avrdude -c avrispv2 -P usb -p m88 -U lfuse:w:0xFF:m -U hfuse:w:0xDF:m
// read current: avrdude -v -c avrispv2 -P usb -p m88
// ATmega88
//------------------------------------------------------------------------------

#include
#include
#include
#include
#define F_CPU 16000000UL
#include

#define BAUD 38400UL // Baudrate

#define UBRR_VAL ((F_CPU+BAUD*8)/(BAUD*16)-1)
#define BAUD_REAL (F_CPU/(16*(UBRR_VAL+1)))
#define BAUD_ERROR ((BAUD_REAL*1000)/BAUD)


//
#define LOOP_CYCLES 8 //Number of cycles that the loop takes
#define us(num) (num/(LOOP_CYCLES*(1/(F_CPU/1000000.0))))


/* Thermometer Connections (At your choice) */
#define THERM_PORT PORTC
#define THERM_DDR DDRC
#define THERM_PIN PINC
#define THERM_DQ PC0
/* Utils */
#define THERM_INPUT_MODE() THERM_DDR&=~(1<
#define THERM_OUTPUT_MODE() THERM_DDR|=(1<
#define THERM_LOW() THERM_PORT&=~(1<
#define THERM_HIGH() THERM_PORT|=(1<

#define THERM_CMD_CONVERTTEMP 0x44
#define THERM_CMD_RSCRATCHPAD 0xbe
#define THERM_CMD_WSCRATCHPAD 0x4e
#define THERM_CMD_CPYSCRATCHPAD 0x48
#define THERM_CMD_RECEEPROM 0xb8
#define THERM_CMD_RPWRSUPPLY 0xb4
#define THERM_CMD_SEARCHROM 0xf0
#define THERM_CMD_READROM 0x33
#define THERM_CMD_MATCHROM 0x55
#define THERM_CMD_SKIPROM 0xcc
#define THERM_CMD_ALARMSEARCH 0xec




void usart_write_char(char data)
{
while (!(UCSR0A & (1<
{
}
UDR0 = data;
}

void usart_write_str(char string[80])
{
while (*string)
{
usart_write_char(*string++);
}
}

// Thermometer
inline __attribute__((gnu_inline)) void therm_delay(uint16_t delay){
while(delay--) asm volatile("nop");
}

uint8_t therm_reset(){
uint8_t i;
//Pull line low and wait for 480uS
THERM_LOW();
THERM_OUTPUT_MODE();
therm_delay(us(480));
//Release line and wait for 60uS
THERM_INPUT_MODE();
therm_delay(us(60));
//Store line value and wait until the completion of 480uS period
i=(THERM_PIN & (1<
therm_delay(us(420));
//Return the value read from the presence pulse (0=OK, 1=WRONG)
return i;
}

void therm_write_bit(uint8_t bit){
//Pull line low for 1uS
THERM_LOW();
THERM_OUTPUT_MODE();
therm_delay(us(1));
//If we want to write 1, release the line (if not will keep low)
if(bit) THERM_INPUT_MODE();
//Wait for 60uS and release the line
therm_delay(us(60));
THERM_INPUT_MODE();
}

uint8_t therm_read_bit(void){
uint8_t bit=0;
//Pull line low for 1uS
THERM_LOW();
THERM_OUTPUT_MODE();
therm_delay(us(1));
//Release line and wait for 14uS
THERM_INPUT_MODE();
therm_delay(us(14));
//Read line value
if(THERM_PIN&(1< //Wait for 45uS to end and return read value
therm_delay(us(45));
return bit;
}

uint8_t therm_read_byte(void){
uint8_t i=8, n=0;
while(i--){
//Shift one position right and store read value
n>>=1;
n|=(therm_read_bit()<<7);
}
return n;
}

void therm_write_byte(uint8_t byte){
uint8_t i=8;
while(i--){
//Write actual bit and shift one position right to make the next bit ready
therm_write_bit(byte&1);
byte>>=1;
}
}


#define THERM_DECIMAL_STEPS_12BIT 625 //.0625
#define THERM_DECIMAL_STEPS_9BIT 500 //.500

void therm_read_temperature(char *buffer){
// Buffer length must be at least 12bytes long! ["+XXX.XXXX C"]
uint8_t temperature[2];
int8_t digit;
uint16_t decimal;
//Reset, skip ROM and start temperature conversion
therm_reset();
therm_write_byte(THERM_CMD_SKIPROM);
therm_write_byte(THERM_CMD_CONVERTTEMP);
//Wait until conversion is complete
while(!therm_read_bit());
//Reset, skip ROM and send command to read Scratchpad
therm_reset();
therm_write_byte(THERM_CMD_SKIPROM);
therm_write_byte(THERM_CMD_RSCRATCHPAD);
//Read Scratchpad (only 2 first bytes)
temperature[0]=therm_read_byte();
temperature[1]=therm_read_byte();
therm_reset();
sprintf(buffer, "%d.%d
",temperature[0]/2, (temperature[0]&1)*5 );
usart_write_str(buffer);
}


int main(void)
{
unsigned int t, x;
char tmp[255];
char tmp2[255] = "abc
";

DDRB = 0xff;
DDRC = 0x00;

// Init USART
UBRR0H = UBRR_VAL >> 8; // UART Baud Rate Register (high byte)
UBRR0L = UBRR_VAL & 0xFF; // UART Baud Rate Register (low byte)
UCSR0B = (1<<
//UCSR0C = (1<<
UCSR0C = (1<<

//usart_write_char(12); // FF Clear Screen
usart_write_str("

");
usart_write_str("Temp Sensor v0.01
");


while(1) {
PORTB = 255;
_delay_us(100000);
PORTB = 0;
_delay_us(900000);

therm_read_temperature(&tmp);
}
return 0;
}


Das passende Makefile
# Hey Emacs, this is a -*- makefile -*-
#
# WinAVR makefile written by Eric B. Weddington, J�rg Wunsch, et al.
# Released to the Public Domain
# Please read the make user manual!
#
# Additional material for this makefile was submitted by:
# Tim Henigan
# Peter Fleury
# Reiner Patommel
# Sander Pool
# Frederik Rouleau
# Markus Pfaff
#
# 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".
#

# mth 2004/09
# Differences from WinAVR 20040720 sample:
# - DEPFLAGS according to Eric Weddingtion's fix (avrfreaks/gcc-forum)
# - F_OSC Define in CFLAGS and AFLAGS


# MCU name
MCU = atmega88

# Main Oscillator Frequency
# This is only used to define F_OSC in all assembler and c-sources.
F_OSC = 3686400

# 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.
ASRC =



# 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.
EXTRAINCDIRS =


# 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
CDEFS =

# Place -I options here
CINCS =


# 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 = -g$(DEBUG)
CFLAGS += $(CDEFS) $(CINCS)
CFLAGS += -O$(OPT)
CFLAGS += -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums
CFLAGS += -Wall -Wstrict-prototypes
CFLAGS += -Wa,-adhlns=$(<:.c=.lst)
CFLAGS += $(patsubst %,-I%,$(EXTRAINCDIRS))
CFLAGS += $(CSTANDARD)
CFLAGS += -DF_OSC=$(F_OSC)



# 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=$(<:.S=.lst),-gstabs
ASFLAGS += -DF_OSC=$(F_OSC)


#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

PRINTF_LIB =

# 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

SCANF_LIB =

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

EXTMEMOPTS =

# 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
LDFLAGS += $(EXTMEMOPTS)
LDFLAGS += $(PRINTF_LIB) $(SCANF_LIB) $(MATH_LIB)




# 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.
#
#AVRDUDE_PROGRAMMER = stk500
AVRDUDE_PROGRAMMER = avrispv2


# com1 = serial port. Use lpt1 to connect to parallel port.
#AVRDUDE_PORT = com1 # programmer connected to serial device
AVRDUDE_PORT = usb


AVRDUDE_WRITE_FLASH = -U flash:w:$(TARGET).hex
#AVRDUDE_WRITE_EEPROM = -U eeprom:w:$(TARGET).eep


# 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.
#AVRDUDE_ERASE_COUNTER = -y

# Uncomment the following if you do /not/ wish a verification to be
# performed after programming the device.
#AVRDUDE_NO_VERIFY = -V

# Increase verbosity level. Please use this when submitting bug
# reports about avrdude. See
# to submit bug reports.
AVRDUDE_VERBOSE = -vv


AVRDUDE_FLAGS = -p $(MCU) -P $(AVRDUDE_PORT) -c $(AVRDUDE_PROGRAMMER)
AVRDUDE_FLAGS += $(AVRDUDE_NO_VERIFY)
AVRDUDE_FLAGS += $(AVRDUDE_VERBOSE)
AVRDUDE_FLAGS += $(AVRDUDE_ERASE_COUNTER)
AVRDUDE_FLAGS += -B 10



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

# Define directories, if needed.
DIRAVR = c:/winavr
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
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_CFLAGS = -mmcu=$(MCU) -I. $(CFLAGS) $(GENDEPFLAGS)
ALL_ASFLAGS = -mmcu=$(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.
begin:
@echo
@echo $(MSG_BEGIN)

finished:
@echo $(MSG_ERRORS_NONE)

end:
@echo $(MSG_END)
@echo


# Display size of file.
HEXSIZE = $(SIZE) --target=$(FORMAT) $(TARGET).hex
ELFSIZE = $(SIZE) -A $(TARGET).elf
sizebefore:
@if [ -f $(TARGET).elf ]; then echo; echo $(MSG_SIZE_BEFORE); $(ELFSIZE); echo; fi

sizeafter:
@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
$(AVRDUDE) $(AVRDUDE_FLAGS) $(AVRDUDE_WRITE_FLASH) $(AVRDUDE_WRITE_EEPROM)




# 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
@echo $(MSG_COFF) $(TARGET).cof
$(COFFCONVERT) -O coff-avr $< $(TARGET).cof


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



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

%.eep: %.elf
@echo
@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
@echo
@echo $(MSG_EXTENDED_LISTING) $@
$(OBJDUMP) -h -S $< > $@

# Create a symbol table from ELF output file.
%.sym: %.elf
@echo
@echo $(MSG_SYMBOL_TABLE) $@
$(NM) -n $< > $@



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


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



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

clean_list :
@echo
@echo $(MSG_CLEANING)
$(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)
$(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




2 Comments

00Blont 2011-04-06 00:16 ^ 50

Posts: 15
Pages: 2
Registered: 2011-01-04
Zum Thema: Digitale Temperatursensoren hier mal ein paar weitere (Stand 5.4.2011):

0.94EU TC77-SPI-SOT23-125°C-Farnell
1.51EU MCP9802-I²C-SOT23A-125°C-Farnell
1.75 TMP100-I²C-SOT23-6-125°C-Farnell
1.80EU LM74-SPI-SOIC8-125°C-Farnell
2.15EU TMP101_I²C_SOT23-6_125°C_Farnell
2.30EU LM95071-SPI-SOT23-150°C-Farnell
2.40EU TMP05-PWM-SOT23-150°C-Farnell
2.97EU AD7415-I²C-SOT23-125°C-Farnell
3.20EU AD7814-SPI-SOT23-125°CFarnell
3.94EU ADT7301-SPI-SOT23-150°C-Farnell
LinkS zu Temp. Sensors von:
-National: http://www.national.com/analog/temp_sensors
-Analog Devices: http://www.analog.com/en/sensors/digital-temperature-sensors/products/index.html

Sorry die meisten Dinger hab ich einfach bei Farnell eigegeben gibt's sicher auch anderswo. Augenmerk: Preis, kleines Gehäuse, bekanntes Protokoll.

Für interessierte hier noch ein paar Tips von Analog Devices:
Temperature Measurement Theory and Practical Techniques:
http://www.analog.com/static/imported-files/application_notes/AN_892.pdf

00Blont 2011-04-06 23:31 ^ 51

Posts: 15
Pages: 2
Registered: 2011-01-04
Einen hab ich noch:
1.60EU LM73-SMBUS-SOT23-150°C-Farnell