contiki/platform/avr-rss2/dev/i2c.c
2016-02-22 20:46:07 +01:00

229 lines
6.0 KiB
C

/*
* Copyright (c) 2010, Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
/**
* \file
* i2c core functions
* \author
* Robert Olsson <robert@radio-sensors.com>
*/
#include <avr/pgmspace.h>
#include <avr/pgmspace.h>
#include <avr/sleep.h>
#include <avr/wdt.h>
#include "dev/watchdog.h"
#include "contiki.h"
#include "i2c.h"
#include <compat/twi.h>
#include <stdio.h>
#include <string.h>
#include "dev/co2_sa_kxx-sensor.h"
void
i2c_init(uint32_t speed)
{
/* initialize TWI clock: 100 kHz clock, TWPS = 0 => prescaler = 1 */
TWSR = 0; /* no prescaler */
TWBR = ((F_CPU / speed) - 16) / 2; /* must be > 10 for stable operation */
}
uint8_t
i2c_start(uint8_t addr)
{
uint8_t twst;
uint32_t n;
/* Send START condition */
TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
/* Wait until transmission completed */
for(n = 0; n < 100000 && !(TWCR & (1 << TWINT)); n++) {
}
if(n >= 100000) {
return 1;
}
/* 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 = addr;
TWCR = (1 << TWINT) | (1 << TWEN);
/* wail until transmission completed and ACK/NACK has been received */
for(n = 0; n < 100000 && !(TWCR & (1 << TWINT)); n++) {
}
if(n >= 100000) {
return 1;
}
/* 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;
}
void
i2c_start_wait(uint8_t addr)
{
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 = addr;
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;
}
}
void
i2c_stop(void)
{
TWCR = (1 << TWINT) | (1 << TWSTO) | (1 << TWEN);
/* wait until ready */
while(TWCR & (1<<TWSTO));
}
void
i2c_write(uint8_t u8data)
{
TWDR = u8data;
TWCR = (1 << TWINT) | (1 << TWEN);
while((TWCR & (1 << TWINT)) == 0) ;
}
uint8_t
i2c_readAck(void)
{
TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
while((TWCR & (1 << TWINT)) == 0) ;
return TWDR;
}
uint8_t
i2c_readNak(void)
{
TWCR = (1 << TWINT) | (1 << TWEN);
while((TWCR & (1 << TWINT)) == 0) ;
return TWDR;
}
static void
print_delim(int p, char *s, const char *d)
{
if(p) {
printf("%s", d);
}
printf("%s", s);
}
void
i2c_write_mem(uint8_t addr, uint8_t reg, uint8_t value)
{
i2c_start(addr | I2C_WRITE);
i2c_write(reg);
i2c_write(value);
i2c_stop();
}
void
i2c_read_mem(uint8_t addr, uint8_t reg, uint8_t buf[], uint8_t bytes)
{
uint8_t i = 0;
i2c_start(addr | I2C_WRITE);
i2c_write(reg);
i2c_start(addr | I2C_READ);
for(i = 0; i < bytes; i++) {
if(i == bytes - 1) {
buf[i] = i2c_readNak();
} else {
buf[i] = i2c_readAck();
}
}
i2c_stop();
}
void
i2c_at24mac_read(char *buf, uint8_t eui64)
{
if(eui64) {
i2c_read_mem(I2C_AT24MAC_ADDR, 0x98, (uint8_t *)buf, 8);
}
/* 128bit unique serial number */
else {
i2c_read_mem(I2C_AT24MAC_ADDR, 0x80, (uint8_t *)buf, 16);
}
}
uint16_t
i2c_probe(void)
{
int p = 0;
const char *del = ",";
uint16_t probed = 0;
watchdog_periodic();
if(!i2c_start(I2C_AT24MAC_ADDR)) {
i2c_stop();
probed |= I2C_AT24MAC;
print_delim(p++, "AT24MAC", del);
}
watchdog_periodic();
if(!i2c_start(I2C_SHT2X_ADDR)) {
i2c_stop();
probed |= I2C_SHT2X;
print_delim(p++, "SHT2X", del);
}
watchdog_periodic();
if(!i2c_start(I2C_CO2SA_ADDR)) {
i2c_stop();
probed |= I2C_CO2SA;
print_delim(p++, "CO2SA", del);
}
return probed;
}