/*
    avr_twi.h

    Copyright 2008, 2009 Michel Pollet <buserror@gmail.com>

    This file is part of simavr.

    simavr 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 3 of the License, or
    (at your option) any later version.

    simavr 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 simavr.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef __AVR_TWI_H__
#define __AVR_TWI_H__

#ifdef __cplusplus
extern "C" {
#endif

#include "sim_avr.h"

//#include "sim_twi.h"

enum {
    TWI_IRQ_INPUT = 0,
    TWI_IRQ_OUTPUT,
    TWI_IRQ_STATUS,
    TWI_IRQ_COUNT
};

enum {
    TWI_COND_START = (1 << 0),
    TWI_COND_STOP = (1 << 1),
    TWI_COND_ADDR = (1 << 2),
    TWI_COND_ACK = (1 << 3),
    TWI_COND_WRITE = (1 << 4),
    TWI_COND_READ = (1 << 5),
    // internal state, do not use in irq messages
    TWI_COND_SLAVE    = (1 << 6),
};

typedef struct avr_twi_msg_t {
    uint32_t unused : 8,
        msg : 8,
        addr : 8,
        data : 8;
} avr_twi_msg_t;

typedef struct avr_twi_msg_irq_t {
    union {
        uint32_t v;
        avr_twi_msg_t twi;
    } u;
} avr_twi_msg_irq_t;

// add port number to get the real IRQ
#define AVR_IOCTL_TWI_GETIRQ(_name) AVR_IOCTL_DEF('t','w','i',(_name))

typedef struct avr_twi_t {
    avr_io_t    io;
    char name;

    avr_regbit_t    disabled;    // bit in the PRR

    avr_io_addr_t    r_twbr;            // bit rate register
    avr_io_addr_t    r_twcr;            // control register
    avr_io_addr_t    r_twsr;            // status register
    avr_io_addr_t    r_twar;            // address register (slave)
    avr_io_addr_t    r_twamr;        // address mask register
    avr_io_addr_t    r_twdr;            // data register
    
    avr_regbit_t twen;        // twi enable bit
    avr_regbit_t twea;        // enable acknowledge bit
    avr_regbit_t twsta;        // start condition
    avr_regbit_t twsto;        // stop condition
    avr_regbit_t twwc;        // write collision
    
    avr_regbit_t twsr;        // status registers, (5 bits)
    avr_regbit_t twps;        // prescaler bits (2 bits)
    
    avr_int_vector_t twi;    // twi interrupt

    uint8_t state;
    uint8_t peer_addr;
    uint8_t next_twstate;
} avr_twi_t;

void avr_twi_init( avr_t* avr, avr_twi_t* port );

/*
 * Create a message value for twi including the 'msg' bitfield,
 * 'addr' and data. This value is what is sent as the IRQ value
 */
uint32_t avr_twi_irq_msg( uint8_t msg, uint8_t addr, uint8_t data);

#ifdef __cplusplus
};
#endif

#endif /*__AVR_TWI_H__*/
