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