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.
Code:#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; }Code:/************************************************************************* * 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.Code:/************************************************************************* * 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 */
Könnt ihr mir einen Tipp geben, wo es hakt? Es ist ausschließlich ein SW Problem. Mit einem Bascom Code funktionierts
Grüße hacker
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