osd-contiki/platform/z1/dev/i2cmaster.c

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/*
* 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.
*
* This file is part of the Contiki operating system.
*
*/
/**
* \file
* I2C communication device drivers for Zolertia Z1 sensor node.
* \author
* Enric M. Calvo, Zolertia <ecalvo@zolertia.com>
* Marcus Lundén, SICS <mlunden@sics.se>
*/
#include "i2cmaster.h"
#include "isr_compat.h"
signed char tx_byte_ctr, rx_byte_ctr;
unsigned char rx_buf[2];
unsigned char* tx_buf_ptr;
unsigned char* rx_buf_ptr;
unsigned char receive_data;
unsigned char transmit_data1;
unsigned char transmit_data2;
volatile unsigned int i; // volatile to prevent optimization
//------------------------------------------------------------------------------
// void i2c_receiveinit(unsigned char slave_address,
// unsigned char prescale)
//
// This function initializes the USCI module for master-receive operation.
//
// IN: unsigned char slave_address => Slave Address
// unsigned char prescale => SCL clock adjustment
//-----------------------------------------------------------------------------
void
i2c_receiveinit(uint8_t slave_address) {
UCB1CTL1 = UCSWRST; // Enable SW reset
UCB1CTL0 = UCMST + UCMODE_3 + UCSYNC; // I2C Master, synchronous mode
UCB1CTL1 = UCSSEL_2 | UCSWRST; // Use SMCLK, keep SW reset
UCB1BR0 = I2C_PRESC_400KHZ_LSB; // prescaler for 400 kHz data rate
UCB1BR1 = I2C_PRESC_400KHZ_MSB;
UCB1I2CSA = slave_address; // set slave address
UCB1CTL1 &= ~UCTR; // I2C Receiver
UCB1CTL1 &= ~UCSWRST; // Clear SW reset, resume operation
UCB1I2CIE = UCNACKIE;
#if I2C_RX_WITH_INTERRUPT
UC1IE = UCB1RXIE; // Enable RX interrupt if desired
#endif
}
//------------------------------------------------------------------------------
// void i2c_transmitinit(unsigned char slave_address,
// unsigned char prescale)
//
// Initializes USCI for master-transmit operation.
//
// IN: unsigned char slave_address => Slave Address
// unsigned char prescale => SCL clock adjustment
//------------------------------------------------------------------------------
void
i2c_transmitinit(uint8_t slave_address) {
UCB1CTL1 |= UCSWRST; // Enable SW reset
UCB1CTL0 |= (UCMST | UCMODE_3 | UCSYNC); // I2C Master, synchronous mode
UCB1CTL1 = UCSSEL_2 + UCSWRST; // Use SMCLK, keep SW reset
UCB1BR0 = I2C_PRESC_400KHZ_LSB; // prescaler for 400 kHz data rate
UCB1BR1 = I2C_PRESC_400KHZ_MSB;
UCB1I2CSA = slave_address; // Set slave address
UCB1CTL1 &= ~UCSWRST; // Clear SW reset, resume operation
UCB1I2CIE = UCNACKIE;
UC1IE = UCB1TXIE; // Enable TX ready interrupt
}
//------------------------------------------------------------------------------
// void i2c_receive_n(unsigned char byte_ctr, unsigned char * rx_buf)
// This function is used to start an I2C communication in master-receiver mode WITHOUT INTERRUPTS
// for more than 1 byte
// IN: unsigned char byte_ctr => number of bytes to be read
// OUT: unsigned char rx_buf => receive data buffer
// OUT: int n_received => number of bytes read
//------------------------------------------------------------------------------
static volatile uint8_t rx_byte_tot = 0;
uint8_t
i2c_receive_n(uint8_t byte_ctr, uint8_t *rx_buf) {
rx_byte_tot = byte_ctr;
rx_byte_ctr = byte_ctr;
rx_buf_ptr = rx_buf;
while ((UCB1CTL1 & UCTXSTT) || (UCB1STAT & UCNACKIFG)) // Slave acks address or not?
PRINTFDEBUG ("____ UCTXSTT not clear OR NACK received\n");
#if I2C_RX_WITH_INTERRUPT
PRINTFDEBUG(" RX Interrupts: YES \n");
// SPECIAL-CASE: Stop condition must be sent while receiving the 1st byte for 1-byte only read operations
if(rx_byte_tot == 1){ // See page 537 of slau144e.pdf
dint();
UCB1CTL1 |= UCTXSTT; // I2C start condition
while(UCB1CTL1 & UCTXSTT) // Waiting for Start bit to clear
PRINTFDEBUG ("____ STT clear wait\n");
UCB1CTL1 |= UCTXSTP; // I2C stop condition
eint();
}
else{ // all other cases
UCB1CTL1 |= UCTXSTT; // I2C start condition
}
return 0;
#else
uint8_t n_received = 0;
PRINTFDEBUG(" RX Interrupts: NO \n");
UCB1CTL1 |= UCTXSTT; // I2C start condition
while (rx_byte_ctr > 0){
if (UC1IFG & UCB1RXIFG) { // Waiting for Data
rx_buf[rx_byte_tot - rx_byte_ctr] = UCB1RXBUF;
rx_byte_ctr--;
UC1IFG &= ~UCB1RXIFG; // Clear USCI_B1 RX int flag
n_received++;
}
}
UCB1CTL1 |= UCTXSTP; // I2C stop condition
return n_received;
#endif
}
//------------------------------------------------------------------------------
// uint8_t i2c_busy()
//
// This function is used to check if there is communication in progress.
//
// OUT: unsigned char => 0: I2C bus is idle,
// 1: communication is in progress
//------------------------------------------------------------------------------
uint8_t
i2c_busy(void) {
return (UCB1STAT & UCBBUSY);
}
/*----------------------------------------------------------------------------*/
/* Setup ports and pins for I2C use. */
void
i2c_enable(void) {
I2C_PxSEL |= (I2C_SDA | I2C_SCL); // Secondary function (USCI) selected
I2C_PxSEL2 |= (I2C_SDA | I2C_SCL); // Secondary function (USCI) selected
I2C_PxDIR |= I2C_SCL; // SCL is output (not needed?)
I2C_PxDIR &= ~I2C_SDA; // SDA is input (not needed?)
I2C_PxREN |= (I2C_SDA | I2C_SCL); // Activate internal pull-up/-down resistors
I2C_PxOUT |= (I2C_SDA | I2C_SCL); // Select pull-up resistors
}
/*----------------------------------------------------------------------------*/
//------------------------------------------------------------------------------
// void i2c_transmit_n(unsigned char byte_ctr, unsigned char *field)
//
// This function is used to start an I2C communication in master-transmit mode.
//
// IN: unsigned char byte_ctr => number of bytes to be transmitted
// unsigned char *tx_buf => Content to transmit. Read and transmitted from [0] to [byte_ctr]
//------------------------------------------------------------------------------
static volatile uint8_t tx_byte_tot = 0;
void
i2c_transmit_n(uint8_t byte_ctr, uint8_t *tx_buf) {
tx_byte_tot = byte_ctr;
tx_byte_ctr = byte_ctr;
tx_buf_ptr = tx_buf;
UCB1CTL1 |= UCTR + UCTXSTT; // I2C TX, start condition
}
/*----------------------------------------------------------------------------*/
ISR(USCIAB1TX, i2c_tx_interrupt)
{
// TX Part
if (UC1IFG & UCB1TXIFG) { // TX int. condition
if (tx_byte_ctr == 0) {
UCB1CTL1 |= UCTXSTP; // I2C stop condition
UC1IFG &= ~UCB1TXIFG; // Clear USCI_B1 TX int flag
}
else {
UCB1TXBUF = tx_buf_ptr[tx_byte_tot - tx_byte_ctr];
tx_byte_ctr--;
}
}
// RX Part
#if I2C_RX_WITH_INTERRUPT
else if (UC1IFG & UCB1RXIFG){ // RX int. condition
if (rx_byte_ctr == 0){
// Only for 1-byte transmissions, STOP is handled in receive_n_int
if (rx_byte_tot != 1)
UCB1CTL1 |= UCTXSTP; // I2C stop condition
UC1IFG &= ~UCB1RXIFG; // Clear USCI_B1 RX int flag. XXX Just in case, check if necessary
}
else {
rx_buf_ptr[rx_byte_tot - rx_byte_ctr] = UCB1RXBUF;
rx_byte_ctr--;
}
}
#endif
}
ISR(USCIAB1RX, i2c_rx_interrupt)
{
if(UCB1STAT & UCNACKIFG) {
PRINTFDEBUG("!!! NACK received in RX\n");
UCB1CTL1 |= UCTXSTP;
UCB1STAT &= ~UCNACKIFG;
}
}