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/*
i2c_eeprom.c
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/>.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "sim_avr.h"
#include "avr_twi.h"
#include "i2c_eeprom.h"
/*
* called when a RESET signal is sent
*/
static void
i2c_eeprom_in_hook(
struct avr_irq_t * irq,
uint32_t value,
void * param)
{
i2c_eeprom_t * p = (i2c_eeprom_t*)param;
avr_twi_msg_irq_t v;
v.u.v = value;
/*
* If we receive a STOP, check it was meant to us, and reset the transaction
*/
if (v.u.twi.msg & TWI_COND_STOP) {
if (p->selected) {
// it was us !
if (p->verbose)
printf("eeprom received stop\n");
}
p->selected = 0;
p->index = 0;
p->reg_addr = 0;
}
/*
* if we receive a start, reset status, check if the slave address is
* meant to be us, and if so reply with an ACK bit
*/
if (v.u.twi.msg & TWI_COND_START) {
p->selected = 0;
p->index = 0;
if ((p->addr_base & ~p->addr_mask) == (v.u.twi.addr & ~p->addr_mask)) {
// it's us !
if (p->verbose)
printf("eeprom received start\n");
p->selected = v.u.twi.addr;
avr_raise_irq(p->irq + TWI_IRQ_INPUT,
avr_twi_irq_msg(TWI_COND_ACK, p->selected, 1));
}
}
/*
* If it's a data transaction, first check it is meant to be us (we
* received the correct address and are selected)
*/
if (p->selected) {
/*
* This is a write transaction, first receive as many address bytes
* as we need, then set the address register, then start
* writing data,
*/
if (v.u.twi.msg & TWI_COND_WRITE) {
// address size is how many bytes we use for address register
avr_raise_irq(p->irq + TWI_IRQ_INPUT,
avr_twi_irq_msg(TWI_COND_ACK, p->selected, 1));
int addr_size = p->size > 256 ? 2 : 1;
if (p->index < addr_size) {
p->reg_addr |= (v.u.twi.data << (p->index * 8));
if (p->index == addr_size-1) {
// add the slave address, if relevant
p->reg_addr += ((p->selected & 1) - p->addr_base) << 7;
if (p->verbose)
printf("eeprom set address to 0x%04x\n", p->reg_addr);
}
} else {
if (p->verbose)
printf("eeprom WRITE data 0x%04x: %02x\n", p->reg_addr, v.u.twi.data);
p->ee[p->reg_addr++] = v.u.twi.data;
}
p->reg_addr &= (p->size -1);
p->index++;
}
/*
* It's a read transaction, just send the next byte back to the master
*/
if (v.u.twi.msg & TWI_COND_READ) {
if (p->verbose)
printf("eeprom READ data 0x%04x: %02x\n", p->reg_addr, p->ee[p->reg_addr]);
uint8_t data = p->ee[p->reg_addr++];
avr_raise_irq(p->irq + TWI_IRQ_INPUT,
avr_twi_irq_msg(TWI_COND_READ, p->selected, data));
p->reg_addr &= (p->size -1);
p->index++;
}
}
}
static const char * _ee_irq_names[2] = {
[TWI_IRQ_INPUT] = "8>eeprom.out",
[TWI_IRQ_OUTPUT] = "32<eeprom.in",
};
void
i2c_eeprom_init(
struct avr_t * avr,
i2c_eeprom_t * p,
uint8_t addr,
uint8_t mask,
uint8_t * data,
size_t size)
{
memset(p, 0, sizeof(*p));
memset(p->ee, 0xff, sizeof(p->ee));
p->addr_base = addr;
p->addr_mask = mask;
p->irq = avr_alloc_irq(&avr->irq_pool, 0, 2, _ee_irq_names);
avr_irq_register_notify(p->irq + TWI_IRQ_OUTPUT, i2c_eeprom_in_hook, p);
p->size = size > sizeof(p->ee) ? sizeof(p->ee) : size;
if (data)
memcpy(p->ee, data, p->size);
}
void
i2c_eeprom_attach(
struct avr_t * avr,
i2c_eeprom_t * p,
uint32_t i2c_irq_base )
{
// "connect" the IRQs of the eeprom to the TWI/i2c master of the AVR
avr_connect_irq(
p->irq + TWI_IRQ_INPUT,
avr_io_getirq(avr, i2c_irq_base, TWI_IRQ_INPUT));
avr_connect_irq(
avr_io_getirq(avr, i2c_irq_base, TWI_IRQ_OUTPUT),
p->irq + TWI_IRQ_OUTPUT );
}
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