i2c mit fleury lib

[hacker]

Hallo zusammen,

ich hab vor Bascom an den Nagel zu hängen und mit C anzufangen. Ich versuch mich grad mit I2C zwei PCF8574 anzusprechen mit der Fleury Lib.
Jedoch will das nicht so recht.


#include <uart.h>
#include <i2cmaster.h>
#include <avr/interrupt.h>
#include <util/delay.h>


#define PCF8574_1 0x40
#define PCF8574_2 0x42




void init_all(void)
{
uart_init();
i2c_init();
}

void set_pll_frequency(unsigned char decade1_2, unsigned char decade3_4)
{
i2c_start_wait(PCF8574_1+I2C_WRITE);
i2c_write(decade1_2);
i2c_stop();

i2c_start_wait(PCF8574_2+I2C_WRITE);
i2c_write(decade3_4);
i2c_stop();
}




int main(void)
{
init_all();

sei();

_delay_ms(1000);

set_pll_frequency(0x00, 0x50);

while (1)
{

}

return 0;
}

/************************************************** ***********************
* Title: I2C master library using hardware TWI interface
* Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury
* File: $Id: twimaster.c,v 1.3 2005/07/02 11:14:21 Peter Exp $
* Software: AVR-GCC 3.4.3 / avr-libc 1.2.3
* Target: any AVR device with hardware TWI
* Usage: API compatible with I2C Software Library i2cmaster.h
************************************************** ************************/
#include <inttypes.h>
#include <compat/twi.h>

#include <i2cmaster.h>


/* define CPU frequency in Mhz here if not defined in Makefile */
#ifndef F_CPU
#define F_CPU 16000000UL
#endif

/* I2C clock in Hz */
#define SCL_CLOCK 100000L


/************************************************** ***********************
Initialization of the I2C bus interface. Need to be called only once
************************************************** ***********************/
void i2c_init(void)
{
/* initialize TWI clock: 100 kHz clock, TWPS = 0 => prescaler = 1 */

TWSR = 0; /* no prescaler */
TWBR = ((F_CPU/SCL_CLOCK)-16)/2; /* must be > 10 for stable operation */

}/* i2c_init */


/************************************************** ***********************
Issues a start condition and sends address and transfer direction.
return 0 = device accessible, 1= failed to access device
************************************************** ***********************/
unsigned char i2c_start(unsigned char address)
{
uint8_t twst;

// send START condition
TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);

// wait until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst != TW_START) && (twst != TW_REP_START)) return 1;

// send device address
TWDR = address;
TWCR = (1<<TWINT) | (1<<TWEN);

// wail until transmission completed and ACK/NACK has been received
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return 1;

return 0;

}/* i2c_start */


/************************************************** ***********************
Issues a start condition and sends address and transfer direction.
If device is busy, use ack polling to wait until device is ready

Input: address and transfer direction of I2C device
************************************************** ***********************/
void i2c_start_wait(unsigned char address)
{
uint8_t twst;


while ( 1 )
{
// send START condition
TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);

// wait until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst != TW_START) && (twst != TW_REP_START)) continue;

// send device address
TWDR = address;
TWCR = (1<<TWINT) | (1<<TWEN);

// wail until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst == TW_MT_SLA_NACK )||(twst ==TW_MR_DATA_NACK) )
{
/* device busy, send stop condition to terminate write operation */
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);

// wait until stop condition is executed and bus released
while(TWCR & (1<<TWSTO));

continue;
}
//if( twst != TW_MT_SLA_ACK) return 1;
break;
}

}/* i2c_start_wait */


/************************************************** ***********************
Issues a repeated start condition and sends address and transfer direction

Input: address and transfer direction of I2C device

Return: 0 device accessible
1 failed to access device
************************************************** ***********************/
unsigned char i2c_rep_start(unsigned char address)
{
return i2c_start( address );

}/* i2c_rep_start */


/************************************************** ***********************
Terminates the data transfer and releases the I2C bus
************************************************** ***********************/
void i2c_stop(void)
{
/* send stop condition */
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);

// wait until stop condition is executed and bus released
while(TWCR & (1<<TWSTO));

}/* i2c_stop */


/************************************************** ***********************
Send one byte to I2C device

Input: byte to be transfered
Return: 0 write successful
1 write failed
************************************************** ***********************/
unsigned char i2c_write( unsigned char data )
{
uint8_t twst;

// send data to the previously addressed device
TWDR = data;
TWCR = (1<<TWINT) | (1<<TWEN);

// wait until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits
twst = TW_STATUS & 0xF8;
if( twst != TW_MT_DATA_ACK) return 1;
return 0;

}/* i2c_write */


/************************************************** ***********************
Read one byte from the I2C device, request more data from device

Return: byte read from I2C device
************************************************** ***********************/
unsigned char i2c_readAck(void)
{
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
while(!(TWCR & (1<<TWINT)));

return TWDR;

}/* i2c_readAck */


/************************************************** ***********************
Read one byte from the I2C device, read is followed by a stop condition

Return: byte read from I2C device
************************************************** ***********************/
unsigned char i2c_readNak(void)
{
TWCR = (1<<TWINT) | (1<<TWEN);
while(!(TWCR & (1<<TWINT)));

return TWDR;

}/* i2c_readNak */


/************************************************** ***********************
* Title: I2C master library using hardware TWI interface
* Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury
* File: $Id: twimaster.c,v 1.3 2005/07/02 11:14:21 Peter Exp $
* Software: AVR-GCC 3.4.3 / avr-libc 1.2.3
* Target: any AVR device with hardware TWI
* Usage: API compatible with I2C Software Library i2cmaster.h
************************************************** ************************/
#include <inttypes.h>
#include <compat/twi.h>

#include <i2cmaster.h>


/* define CPU frequency in Mhz here if not defined in Makefile */
#ifndef F_CPU
#define F_CPU 16000000UL
#endif

/* I2C clock in Hz */
#define SCL_CLOCK 100000L


/************************************************** ***********************
Initialization of the I2C bus interface. Need to be called only once
************************************************** ***********************/
void i2c_init(void)
{
/* initialize TWI clock: 100 kHz clock, TWPS = 0 => prescaler = 1 */

TWSR = 0; /* no prescaler */
TWBR = ((F_CPU/SCL_CLOCK)-16)/2; /* must be > 10 for stable operation */

}/* i2c_init */


/************************************************** ***********************
Issues a start condition and sends address and transfer direction.
return 0 = device accessible, 1= failed to access device
************************************************** ***********************/
unsigned char i2c_start(unsigned char address)
{
uint8_t twst;

// send START condition
TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);

// wait until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst != TW_START) && (twst != TW_REP_START)) return 1;

// send device address
TWDR = address;
TWCR = (1<<TWINT) | (1<<TWEN);

// wail until transmission completed and ACK/NACK has been received
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return 1;

return 0;

}/* i2c_start */


/************************************************** ***********************
Issues a start condition and sends address and transfer direction.
If device is busy, use ack polling to wait until device is ready

Input: address and transfer direction of I2C device
************************************************** ***********************/
void i2c_start_wait(unsigned char address)
{
uint8_t twst;


while ( 1 )
{
// send START condition
TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);

// wait until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst != TW_START) && (twst != TW_REP_START)) continue;

// send device address
TWDR = address;
TWCR = (1<<TWINT) | (1<<TWEN);

// wail until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst == TW_MT_SLA_NACK )||(twst ==TW_MR_DATA_NACK) )
{
/* device busy, send stop condition to terminate write operation */
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);

// wait until stop condition is executed and bus released
while(TWCR & (1<<TWSTO));

continue;
}
//if( twst != TW_MT_SLA_ACK) return 1;
break;
}

}/* i2c_start_wait */


/************************************************** ***********************
Issues a repeated start condition and sends address and transfer direction

Input: address and transfer direction of I2C device

Return: 0 device accessible
1 failed to access device
************************************************** ***********************/
unsigned char i2c_rep_start(unsigned char address)
{
return i2c_start( address );

}/* i2c_rep_start */


/************************************************** ***********************
Terminates the data transfer and releases the I2C bus
************************************************** ***********************/
void i2c_stop(void)
{
/* send stop condition */
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);

// wait until stop condition is executed and bus released
while(TWCR & (1<<TWSTO));

}/* i2c_stop */


/************************************************** ***********************
Send one byte to I2C device

Input: byte to be transfered
Return: 0 write successful
1 write failed
************************************************** ***********************/
unsigned char i2c_write( unsigned char data )
{
uint8_t twst;

// send data to the previously addressed device
TWDR = data;
TWCR = (1<<TWINT) | (1<<TWEN);

// wait until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits
twst = TW_STATUS & 0xF8;
if( twst != TW_MT_DATA_ACK) return 1;
return 0;

}/* i2c_write */


/************************************************** ***********************
Read one byte from the I2C device, request more data from device

Return: byte read from I2C device
************************************************** ***********************/
unsigned char i2c_readAck(void)
{
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
while(!(TWCR & (1<<TWINT)));

return TWDR;

}/* i2c_readAck */


/************************************************** ***********************
Read one byte from the I2C device, read is followed by a stop condition

Return: byte read from I2C device
************************************************** ***********************/
unsigned char i2c_readNak(void)
{
TWCR = (1<<TWINT) | (1<<TWEN);
while(!(TWCR & (1<<TWINT)));

return TWDR;

}/* i2c_readNak */


Das ist der Code. main.c, twimaster.c und i2cmaster.h.


Könnt ihr mir einen Tipp geben, wo es hakt? Es ist ausschließlich ein SW Problem. Mit einem Bascom Code funktionierts ;-)

Grüße hacker

[uffi]

Du hast oben zweimal twimaster.c geposted, aber kein mal i2cmaster.h.

Ich nehme mal an, I2C_WRITE ist in i2cmaster.h definiert.

Versuch doch mal, die I2C Frequenz auf 50 oder sogar 10 kHz zu reduzieren.

Fehler fällt mir aber keiner auf in Deinem Code.

[hacker]

#ifndef _I2CMASTER_H
#define _I2CMASTER_H 1
/************************************************** ***********************
* Title: C include file for the I2C master interface
* (i2cmaster.S or twimaster.c)
* Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury
* File: $Id: i2cmaster.h,v 1.10 2005/03/06 22:39:57 Peter Exp $
* Software: AVR-GCC 3.4.3 / avr-libc 1.2.3
* Target: any AVR device
* Usage: see Doxygen manual
************************************************** ************************/

#ifdef DOXYGEN
/**
@defgroup pfleury_ic2master I2C Master library
@code #include <i2cmaster.h> @endcode

@brief I2C (TWI) Master Software Library

Basic routines for communicating with I2C slave devices. This single master
implementation is limited to one bus master on the I2C bus.

This I2c library is implemented as a compact assembler software implementation of the I2C protocol
which runs on any AVR (i2cmaster.S) and as a TWI hardware interface for all AVR with built-in TWI hardware (twimaster.c).
Since the API for these two implementations is exactly the same, an application can be linked either against the
software I2C implementation or the hardware I2C implementation.

Use 4.7k pull-up resistor on the SDA and SCL pin.

Adapt the SCL and SDA port and pin definitions and eventually the delay routine in the module
i2cmaster.S to your target when using the software I2C implementation !

Adjust the CPU clock frequence F_CPU in twimaster.c or in the Makfile when using the TWI hardware implementaion.

@note
The module i2cmaster.S is based on the Atmel Application Note AVR300, corrected and adapted
to GNU assembler and AVR-GCC C call interface.
Replaced the incorrect quarter period delays found in AVR300 with
half period delays.

@author Peter Fleury pfleury@gmx.ch http://jump.to/fleury

@par API Usage Example
The following code shows typical usage of this library, see example test_i2cmaster.c

@code

#include <i2cmaster.h>


#define Dev24C02 0xA2 // device address of EEPROM 24C02, see datasheet

int main(void)
{
unsigned char ret;

i2c_init(); // initialize I2C library

// write 0x75 to EEPROM address 5 (Byte Write)
i2c_start_wait(Dev24C02+I2C_WRITE); // set device address and write mode
i2c_write(0x05); // write address = 5
i2c_write(0x75); // write value 0x75 to EEPROM
i2c_stop(); // set stop conditon = release bus


// read previously written value back from EEPROM address 5
i2c_start_wait(Dev24C02+I2C_WRITE); // set device address and write mode

i2c_write(0x05); // write address = 5
i2c_rep_start(Dev24C02+I2C_READ); // set device address and read mode

ret = i2c_readNak(); // read one byte from EEPROM
i2c_stop();

for(;;);
}
@endcode

*/
#endif /* DOXYGEN */

/**@{*/

#if (__GNUC__ * 100 + __GNUC_MINOR__) < 304
#error "This library requires AVR-GCC 3.4 or later, update to newer AVR-GCC compiler !"
#endif

#include <avr/io.h>

/** defines the data direction (reading from I2C device) in i2c_start(),i2c_rep_start() */
#define I2C_READ 1

/** defines the data direction (writing to I2C device) in i2c_start(),i2c_rep_start() */
#define I2C_WRITE 0


/**
@brief initialize the I2C master interace. Need to be called only once
@param void
@return none
*/
extern void i2c_init(void);


/**
@brief Terminates the data transfer and releases the I2C bus
@param void
@return none
*/
extern void i2c_stop(void);


/**
@brief Issues a start condition and sends address and transfer direction

@param addr address and transfer direction of I2C device
@retval 0 device accessible
@retval 1 failed to access device
*/
extern unsigned char i2c_start(unsigned char addr);


/**
@brief Issues a repeated start condition and sends address and transfer direction

@param addr address and transfer direction of I2C device
@retval 0 device accessible
@retval 1 failed to access device
*/
extern unsigned char i2c_rep_start(unsigned char addr);


/**
@brief Issues a start condition and sends address and transfer direction

If device is busy, use ack polling to wait until device ready
@param addr address and transfer direction of I2C device
@return none
*/
extern void i2c_start_wait(unsigned char addr);


/**
@brief Send one byte to I2C device
@param data byte to be transfered
@retval 0 write successful
@retval 1 write failed
*/
extern unsigned char i2c_write(unsigned char data);


/**
@brief read one byte from the I2C device, request more data from device
@return byte read from I2C device
*/
extern unsigned char i2c_readAck(void);

/**
@brief read one byte from the I2C device, read is followed by a stop condition
@return byte read from I2C device
*/
extern unsigned char i2c_readNak(void);

/**
@brief read one byte from the I2C device

Implemented as a macro, which calls either i2c_readAck or i2c_readNak

@param ack 1 send ack, request more data from device

0 send nak, read is followed by a stop condition
@return byte read from I2C device
*/
extern unsigned char i2c_read(unsigned char ack);
#define i2c_read(ack) (ack) ? i2c_readAck() : i2c_readNak();


/**@}*/
#endif


Sry, hier auch die i2cmaster.h. Das komische ist ja, dass es mir Bascom funktioniert, auch mit einer Busgeschwindigkeit von 100kHz. Dort gibt es keinerlei Probleme.

[hacker]

Hallo,

der Aufruf von i2c_start() liefert schon eine 1 zurück.


/************************************************** ***********************
* Title: I2C master library using hardware TWI interface
* Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury
* File: $Id: twimaster.c,v 1.3 2005/07/02 11:14:21 Peter Exp $
* Software: AVR-GCC 3.4.3 / avr-libc 1.2.3
* Target: any AVR device with hardware TWI
* Usage: API compatible with I2C Software Library i2cmaster.h
************************************************** ************************/
#include <inttypes.h>
#include <compat/twi.h>

#include <i2c.h>


/* define CPU frequency in Mhz here if not defined in Makefile */
#ifndef F_CPU
#define F_CPU 16000000UL
#endif

/* I2C clock in Hz */
#define SCL_CLOCK 100000L


/************************************************** ***********************
Initialization of the I2C bus interface. Need to be called only once
************************************************** ***********************/
void i2c_init(void)
{
/* initialize TWI clock: 100 kHz clock, TWPS = 0 => prescaler = 1 */

TWSR = 0; /* no prescaler */
TWBR = ((F_CPU/SCL_CLOCK)-16)/2; /* must be > 10 for stable operation */

}/* i2c_init */


/************************************************** ***********************
Issues a start condition and sends address and transfer direction.
return 0 = device accessible, 1= failed to access device
************************************************** ***********************/
unsigned char i2c_start(unsigned char address)
{
uint8_t twst;

// send START condition
TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);

// wait until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst != TW_START) && (twst != TW_REP_START)) return 1;

// send device address
TWDR = address;
TWCR = (1<<TWINT) | (1<<TWEN);

// wail until transmission completed and ACK/NACK has been received
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return 1;

return 0;

}/* i2c_start */


/************************************************** ***********************
Issues a start condition and sends address and transfer direction.
If device is busy, use ack polling to wait until device is ready

Input: address and transfer direction of I2C device
************************************************** ***********************/
void i2c_start_wait(unsigned char address)
{
uint8_t twst;


while ( 1 )
{
// send START condition
TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);

// wait until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst != TW_START) && (twst != TW_REP_START)) continue;

// send device address
TWDR = address;
TWCR = (1<<TWINT) | (1<<TWEN);

// wail until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst == TW_MT_SLA_NACK )||(twst ==TW_MR_DATA_NACK) )
{
/* device busy, send stop condition to terminate write operation */
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);

// wait until stop condition is executed and bus released
while(TWCR & (1<<TWSTO));

continue;
}
//if( twst != TW_MT_SLA_ACK) return 1;
break;
}

}/* i2c_start_wait */


/************************************************** ***********************
Issues a repeated start condition and sends address and transfer direction

Input: address and transfer direction of I2C device

Return: 0 device accessible
1 failed to access device
************************************************** ***********************/
unsigned char i2c_rep_start(unsigned char address)
{
return i2c_start( address );

}/* i2c_rep_start */


/************************************************** ***********************
Terminates the data transfer and releases the I2C bus
************************************************** ***********************/
void i2c_stop(void)
{
/* send stop condition */
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);

// wait until stop condition is executed and bus released
while(TWCR & (1<<TWSTO));

}/* i2c_stop */


/************************************************** ***********************
Send one byte to I2C device

Input: byte to be transfered
Return: 0 write successful
1 write failed
************************************************** ***********************/
unsigned char i2c_write( unsigned char data )
{
uint8_t twst;

// send data to the previously addressed device
TWDR = data;
TWCR = (1<<TWINT) | (1<<TWEN);

// wait until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits
twst = TW_STATUS & 0xF8;
if( twst != TW_MT_DATA_ACK) return 1;
return 0;

}/* i2c_write */


/************************************************** ***********************
Read one byte from the I2C device, request more data from device

Return: byte read from I2C device
************************************************** ***********************/
unsigned char i2c_readAck(void)
{
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
while(!(TWCR & (1<<TWINT)));

return TWDR;

}/* i2c_readAck */


/************************************************** ***********************
Read one byte from the I2C device, read is followed by a stop condition

Return: byte read from I2C device
************************************************** ***********************/
unsigned char i2c_readNak(void)
{
TWCR = (1<<TWINT) | (1<<TWEN);
while(!(TWCR & (1<<TWINT)));

return TWDR;

}/* i2c_readNak */


Habt ihr noch Ideen, an was es liegen könnte? Ich testete es grade eben nochmal mit einem Bascom Code. Dort funktioniert die ganze Geschichte wunderbar.

/edit:


uint8_t twst;

// send START condition
TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);

// wait until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst != TW_START) && (twst != TW_REP_START)) return 1;

Schon direkt nach der Startsequenz schicken funktionierts nicht mehr. Er kommt als nicht mal zum Adresse schicken.

[uffi]

warum testest Du nicht mal 10 KHz TWI Busclock?
Das könnte einen Hinweis auf ein Timing Problem liefern.
Das Timing Problem könnte mit dem Setzen der TWI Register Bits im C-code zusammenhängen.

[hacker]

Ich hab nun ein Takt von 10kHz eingestellt:


void i2c_init(void)
{
/* initialize TWI clock: 100 kHz clock, TWPS = 0 => prescaler = 1 */

//TWSR = 0; /* no prescaler */
//TWBR = ((F_CPU/SCL_CLOCK)-16)/2; /* must be > 10 for stable operation */
TWSR = 1;
TWBR = 192;

}/* i2c_init */

Hier jedoch auch kommt er nur so weit wie im Code eingezeichnet:


unsigned char i2c_start(unsigned char address)
{
uint8_t twst;

// send START condition
TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);

// wait until transmission completed
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst != TW_START) && (twst != TW_REP_START)) return 1;

! HIER KOMMT ER NICHT MEHR HIN!

// send device address
TWDR = address;
TWCR = (1<<TWINT) | (1<<TWEN);

// wail until transmission completed and ACK/NACK has been received
while(!(TWCR & (1<<TWINT)));

// check value of TWI Status Register. Mask prescaler bits.
twst = TW_STATUS & 0xF8;
if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return 1;

return 0;

}/* i2c_start */


Ich bin am verzweifeln...

[Gock]

Hast Du die Optimierung eingeschaltet???
Gruß

[servussssss]

Hallo hacker,

welchen PCF8574 hast du?

Bezeichnung PCF8574 Index "AP" ?
Wenn ja, dieser hat soviel ich weiß andere Adressbits.

Sonst probier es mal mit diesem Code:


i2c_init();
i2c_start_wait(PCF8574_1+I2C_WRITE);
wait(255);
i2c_write(0x00);
wait(255);
i2c_stop();


Ich musste den Atmega noch "bremsen" das es bei mir geklappt hat.

Gruß

[hacker]

Hallo,

Optimierung ist auf -s eingestellt. Ich noch mal die i2c_start() Funktion selber geschrieben. Zwar ästhetisch nicht so schön, aber plötzlich klappts. Wobei eigentlich beide Codes genau das selbe machen. Irgendwie komsich...


TWCR = 0xA4;
do
{
twst = TWCR & 0x80;
}while (twst != 0x80);
twst = TWSR & 0xF8;
if ( (twst != TW_START) && (twst != TW_REP_START)) return 1;
TWDR = address;
TWCR = 0x84;
do
{
twst = TWCR & 0x80;
}while (twst != 0x80);
twst = TWSR & 0xF8;
if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return 1;

return 0;

[uffi]

wenn beide Codes eigentlich das gleiche machen, dann poste doch mal die compilierten und disassemblierten Ergebnisse. Dann kann man es 1:1 vergleichen, wo der Unterschied herkommen könnte.

[Haveaniceday]

Hey, kenne dein Problem. Wenn ich die twimaster.c gegen die I2cmaster.S wechsele, läuft der I2C Bus bei mir aus nicht mehr... Hab auch keine Ahnung woran es liegt :-s
@hacker, Funktioniert es mit deiner Selbstgeschriebenen i2cstart?

[hacker]

Hallo,

mit oben geposteter twi_start() routine läuft es bei mir ohne Probleme. Vielleicht sollte man zur besseren Lesbarkeit, die Hexzahlen in ihre Bitnamen übersetzen, dass man sieht, was gesetzt und gelöscht wird.

Grüße,
hacker

[tranh85bo]

Hallo,
Ich habe die Bibliothek von Fleury durchgelesen.Kann jemand mir erklären, woher bekommt man TW_STATUS,TW_MT_SLA_ACK,TW_MR_SLA_ACK und warum die untere Codezeile die beschreibende Bedeutung hat .


// wait until transmission completed
while(!(TWCR & (1<<TWINT)));
ich glaube ,wenn eine Aktion ausgelöst wird,ist automatisch TWINT auf Null zurückgesetzt.Deshalb ist hier eine endlos Schleife .

Vielen Dank

Mit freundlichen Grüssen