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/*
* c't-Sim - Robotersimulator fuer den c't-Bot
*
* This program is free software; you can redistribute it
* and/or modify it under the terms of the GNU General
* Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your
* option) any later version.
* This program is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU General Public License for more details.
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the Free
* Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307, USA.
*
*/
/*! @file TWI_driver.c
* @brief TWI-Treiber (I2C)
* @author Chris efstathiou hendrix@otenet.gr & Carsten Giesen (info@cnau.de)
* @date 08.04.06
*/
#ifdef MCU
#include <avr/io.h>
#include "TWI_driver.h"
#include "global.h"
/*!
* TWI Bus initialsieren
* @return Resultat der Aktion
*/
int8 Init_TWI(void){
TWAR = OWN_ADR; /*!< Eigenen Slave Adresse setzen */
TWBR = 12; /*!< Setze Baudrate auf 100 KHz */
/*!< 4 MHz xtal */
TWCR = (1<<TWEN); /*!< TWI-Interface einschalten */
return 1;
}
/*!
* TWI Buss schliesen
* @return Resultat der Aktion
*/
int8 Close_TWI(void){
TWCR = (0<<TWEN); /*!< TWI-Interface ausschalten */
return 0;
}
/*!
* Warte auf TWI interrupt
*/
void Wait_TWI_int(void){
while (!(TWCR & (1<<TWINT)))
;
}
/*!
* Sende Start Sequence
* @return Resultat der Aktion
*/
uint8 Send_start(void){
TWCR = ((1<<TWINT)+(1<<TWSTA)+(1<<TWEN)); /*!< Sende START */
Wait_TWI_int(); /*!< Warte auf TWI interrupt */
if((TWSR != START)&&(TWSR != REP_START)) /*!< Ist der Status ein Anderer als Start (0x08) oder wiederholter Start (0x10) */
return TWSR; /*!< -> error und Rueckgabe TWSR. */
return SUCCESS; /*!< wenn OK Rueckgabe SUCCESS */
}
/*!
* Sende Stop Sequence
*/
void Send_stop(void){
TWCR = ((1<<TWEN)+(1<<TWINT)+(1<<TWSTO));
}
/*!
* Hier wird der eigentliche TWI-Treiber angesprochen
* @param *data_pack Container mit den Daten fuer den Treiber
* @return Resultat der Aktion
*/
uint8 Send_to_TWI(tx_type *data_pack){
uint8 state,i,j;
state = SUCCESS;
for(i=0;(data_pack[i].slave_adr != OWN_ADR)&&(state == SUCCESS);i++) {
state = Send_start();
if (state == SUCCESS)
state = Send_adr(data_pack[i].slave_adr);
/*!
* Abhaengig von W/R senden oder empfangen
*/
if(!(data_pack[i].slave_adr & R)) {
if (state == SUCCESS){
/*!
* Wenn W bis alle Daten gesendet sind
*/
for(j=0;((j<data_pack[i].size)&&(state == SUCCESS));j++)
state = Send_byte(data_pack[i].data_ptr[j]);
}
}
else{
if (state == MRX_ADR_NACK) {
state = Send_start();
}
if (state == SUCCESS){
/*!
* Wenn R bis alle Daten empfangen sind
*/
for(j=0;((j<data_pack[i].size)&&(state == SUCCESS));j++){
/*!
* Wenn wir keine Daten mehr erwarten NACK senden
*/
if(j == data_pack[i].size-1)
state = Get_byte(data_pack[i].data_ptr++,0);
else
state = Get_byte(data_pack[i].data_ptr++,1);
}
}
}
Send_stop();
}
Close_TWI();
return state;
}
/*!
* Sende ein Byte
* @param data das zu uebertragende Byte
*/
uint8 Send_byte(uint8 data){
Wait_TWI_int();
TWDR = data;
TWCR = ((1<<TWINT)+(1<<TWEN));
Wait_TWI_int();
if(TWSR != MTX_DATA_ACK)
return TWSR;
return SUCCESS;
}
/*!
* Sende Slave Adresse
* @param adr die gewuenschte Adresse
* @return Resultat der Aktion
*/
uint8 Send_adr(uint8 adr){
Wait_TWI_int();
TWDR = adr;
TWCR = ((1<<TWINT)+(1<<TWEN));
Wait_TWI_int();
if((TWSR != MTX_ADR_ACK)&&(TWSR != MRX_ADR_ACK))
return TWSR;
return SUCCESS;
}
/*!
* Empfange ein Byte
* @param *rx_ptr Container fuer die Daten
* @param last_byte Flag ob noch Daten erwartet werden
* @return Resultat der Aktion
*/
uint8 Get_byte(uint8 *rx_ptr,uint8 last_byte){
Wait_TWI_int();
if(last_byte)
TWCR = ((1<<TWINT)+(1<<TWEA)+(1<<TWEN));
else
TWCR = ((1<<TWINT)+(1<<TWEN));
Wait_TWI_int();
*rx_ptr = TWDR;
if(((TWSR == MRX_DATA_NACK)&&(last_byte == 0))||(TWSR == MRX_DATA_ACK))
return SUCCESS;
return TWSR;
}
#endif
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