/* * 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; }