331 lines
11 KiB
C
331 lines
11 KiB
C
/*
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* Copyright (c) 2011, Hedde Bosman <heddebosman@incas3.eu>
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*
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* I2C communication device drivers for mc1322x
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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#include "i2c.h"
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#include <stdio.h>
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static int8_t tx_byte_ctr;
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static int8_t rx_byte_ctr;
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static uint8_t* tx_buf_ptr;
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static uint8_t* rx_buf_ptr;
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volatile unsigned int i; // volatile to prevent optimization
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static inline void i2c_send_byte(void) {
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*I2CDR = *(tx_buf_ptr++); // set new byte, MCF is automatically cleared
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tx_byte_ctr--;
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}
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static inline void i2c_recv_byte(void) {
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*(rx_buf_ptr++) = *I2CDR;
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rx_byte_ctr--;
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}
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//------------------------------------------------------------------------------
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// void i2c_receiveinit(uint8_t slave_address,
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// uint8_t prescale)
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//
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// This function initializes the USCI module for master-receive operation.
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//
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// IN: uint8_t slave_address => Slave Address
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// uint8_t prescale => SCL clock adjustment
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//-----------------------------------------------------------------------------
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//static volatile uint8_t rx_byte_tot = 0;
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void i2c_receiveinit(uint8_t slave_address, uint8_t byte_ctr, uint8_t *rx_buf) {
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// wait for bus to be free before setting MSTA (assuming we're in a multi-master environment or still sending something else)
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while(i2c_busy()) /* wait */;
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// assert: rx_byte_ctr <= 0
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// assert: tx_byte_ctr <= 0
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tx_buf_ptr = 0;
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tx_byte_ctr = 0; // indicate that nothing is to be received
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rx_byte_ctr = byte_ctr;
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rx_buf_ptr = rx_buf;
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// clockdiv
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//*I2CFDR = 0x20; // 150 khz for redbee econotag
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// assume being master, thus no addres has to be set
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*I2CCR = I2C_MEN |
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#ifdef I2C_NON_BLOCKING
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I2C_MIEN |
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#endif
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I2C_MSTA | I2C_MTX | I2C_RXAK; // start condition is triggered
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// write out address of slave
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*I2CDR = (slave_address & 0x7f) <<1 | 0x01;
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#ifndef I2C_NON_BLOCKING
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i2c_receive();
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#endif
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}
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//------------------------------------------------------------------------------
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// void i2c_transmitinit(uint8_t slave_address,
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// uint8_t prescale)
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//
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// Initializes USCI for master-transmit operation.
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//
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// IN: uint8_t slave_address => Slave Address
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// uint8_t prescale => SCL clock adjustment
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//------------------------------------------------------------------------------
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//static volatile uint8_t tx_byte_tot = 0;
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void i2c_transmitinit(uint8_t slave_address, uint8_t byte_ctr, uint8_t *tx_buf) {
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// wait for bus to be free before setting MSTA (assuming we're in a multi-master environment or still sending something else)
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while(i2c_busy()) /* wait */;
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// assert: rx_byte_ctr <= 0
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// assert: tx_byte_ctr <= 0
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rx_buf_ptr = 0;
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rx_byte_ctr = 0; // indicate that nothing is to be received
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tx_byte_ctr = byte_ctr;
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tx_buf_ptr = tx_buf;
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// clockdiv
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//*I2CFDR = 0x20; // 150 khz for redbee econotag
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// assume being master, thus no addres has to be set
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*I2CCR = I2C_MEN |
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#ifdef I2C_NON_BLOCKING
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I2C_MIEN |
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#endif
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I2C_MSTA | I2C_MTX ; // start condition is triggered
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// write out address of slave
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*I2CDR = (slave_address & 0x7f) <<1;
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#ifndef I2C_NON_BLOCKING
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i2c_transmit();
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#endif
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}
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/*----------------------------------------------------------------------------*/
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/*- blocking counterparts of interrupt hanlder function ---------------------*/
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/*----------------------------------------------------------------------------*/
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#ifndef I2C_NON_BLOCKING
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/*----------------------------------------------------------------------------*/
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uint8_t i2c_receive() {
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while(rx_byte_ctr > 0) {
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// busy wait
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while(!(*I2CSR & I2C_MCF) || !(*I2CSR & I2C_MIF)) /*wait*/;
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if (rx_byte_ctr == 1) { // receiving next-to-last byte, thus turn off auto-ack for stop condition
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*I2CCR |= I2C_TXAK;
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}
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if (*I2CSR & I2C_MCF) {
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i2c_recv_byte(); // read new byte
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}
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if (*I2CSR & I2C_MAL) {
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*I2CSR &= ~I2C_MAL; // should be cleared in software
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printf("*** ERROR I2C: Arbitration lost\n");
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// Arbitration lost; ERROR?
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}
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}
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while(!(*I2CSR & I2C_MCF) || !(*I2CSR & I2C_MIF)) /*wait*/;
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if (*I2CSR & I2C_RXAK) {
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// NO acknoledge byte received
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printf("*** ERROR I2C: No ack received\n");
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}
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if (*I2CSR & I2C_MAL) {
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*I2CSR &= ~I2C_MAL; // should be cleared in software
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printf("*** ERROR I2C: Arbitration lost\n");
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// Arbitration lost; ERROR?
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}
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*I2CCR &= ~I2C_MSTA; // stop condition
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}
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/*----------------------------------------------------------------------------*/
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void i2c_transmit() {
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while(tx_byte_ctr > 0) {
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// busy wait
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while(!(*I2CSR & I2C_MCF) || !(*I2CSR & I2C_MIF)) /*wait*/;
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if (*I2CSR & I2C_RXAK) {
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// NO acknoledge byte received
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printf("*** ERROR I2C: No ack received\n");
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}
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if (*I2CSR & I2C_MCF) {
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i2c_send_byte();
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}
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if (*I2CSR & I2C_MAL) {
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*I2CSR &= ~I2C_MAL; // should be cleared in software
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printf("*** ERROR I2C: Arbitration lost\n");
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// Arbitration lost; ERROR?
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}
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// clear MIF
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*I2CSR &= ~I2C_MIF;
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}
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while(!(*I2CSR & I2C_MCF) || !(*I2CSR & I2C_MIF)) /*wait*/;
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if (*I2CSR & I2C_RXAK) {
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// NO acknoledge byte received
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printf("*** ERROR I2C: No ack received\n");
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}
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if (*I2CSR & I2C_MAL) {
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*I2CSR &= ~I2C_MAL; // should be cleared in software
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printf("*** ERROR I2C: Arbitration lost\n");
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// Arbitration lost; ERROR?
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}
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*I2CCR &= ~I2C_MSTA; // stop condition
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}
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#endif
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/*----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------*/
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/* force SCL to become bus master when sda is still low (can occur after sys reset */
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/*----------------------------------------------------------------------------*/
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void i2c_force_reset(void) {
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uint8_t tmp;
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*I2CCR = 0x20;
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*I2CCR = 0xA0;
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tmp = *I2CDR;
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// return to module state Master?
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}
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/*----------------------------------------------------------------------------*/
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/*- check if we're still in the process of sending something ----------------*/
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/*----------------------------------------------------------------------------*/
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uint8_t i2c_transferred(void) {
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return (!i2c_busy() && rx_byte_ctr == 0 && tx_byte_ctr == 0);
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}
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/*----------------------------------------------------------------------------*/
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/* check if there is communication in progress on the i2c bus. */
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/*----------------------------------------------------------------------------*/
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uint8_t i2c_busy(void) {
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return ((*I2CSR & I2C_MBB) > 0); // bit 5 high = busy
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}
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/*----------------------------------------------------------------------------*/
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/* Setup ports and pins for I2C use. */
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/*----------------------------------------------------------------------------*/
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void i2c_enable(void) {
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// enable clock signal to i2c module
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*I2CCKER = I2C_CKEN; // enable
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enable_irq(I2C);
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*I2CFDR = 0x20; // clockdiv: 150 khz for redbee econotag
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*I2CADR = 0x01; // our slave address (not used; we're master)
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// then enable i2c module
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*I2CCR |= I2C_MEN | // module-enable, auto-ack = on
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#ifdef I2C_NON_BLOCKING
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I2C_MIEN | //module-interrupt-enable
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#endif
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0;
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// then switch gpio pins to i2c
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*GPIO_FUNC_SEL0 |= (0x01 << (I2C_SCL*2)) | (0x01 << (I2C_SDA*2)); // GPIO 12, 13 to i2c
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// and enable pull-up resistors
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*GPIO_PAD_PU_EN0 |= (0x01 << I2C_SCL) | (0x01 << I2C_SDA); // Activate internal pull-up/-down resistors
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*GPIO_PAD_PU_SEL0 |= (0x01 << I2C_SCL) | (0x01 << I2C_SDA); // select pull-up resistors for ports
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}
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/*----------------------------------------------------------------------------*/
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/* Reset ports and pins for GPIO use. */
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/*----------------------------------------------------------------------------*/
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void i2c_disable(void) {
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// all control values are set off
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*I2CCR = 0;
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// clock is turned off
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*I2CCKER = ~I2C_CKEN;
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// then switch gpio pins to gpio
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*GPIO_FUNC_SEL0 &= ~(0x01 << (I2C_SCL*2)) | (0x01 << (I2C_SDA*2)); // GPIO 12, 13 to i2c
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// and disable resistors
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*GPIO_PAD_PU_EN0 &= ~(0x01 << I2C_SCL) | (0x01 << I2C_SDA); // Deactivate internal pull-up/-down resistors
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disable_irq(I2C);
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}
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/*----------------------------------------------------------------------------*/
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/*- i2c interrupt handler --------------------------------------------------*/
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/*----------------------------------------------------------------------------*/
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#ifdef I2C_NON_BLOCKING
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void i2c_isr (void) {
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uint8_t dummy;
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if (*I2CSR & I2C_MIF) { // interrupt is from i2c
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if (*I2CSR & I2C_MCF) { // one byte transferred/received. will be cleared automatically when I2CDR is written or I2CSR read
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if (tx_buf_ptr != 0) { // we're sending
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if (*I2CSR & I2C_RXAK) {
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// NO acknoledge byte received
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printf("*** ERROR I2C: No ack received\n");
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}
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if (tx_byte_ctr > 0) { // tx
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i2c_send_byte(); // set new byte, MCF is automatically cleared
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} else {
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*I2CCR &= ~I2C_MSTA; // generate stop condition
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}
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} else { //if (rx_buf_ptr != 0) { // receive
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if (rx_byte_ctr == 1) { // receiving next-to-last byte, thus turn off auto-ack for stop condition
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*I2CCR |= I2C_TXAK;
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}
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if (*I2CCR & I2C_MTX) { // address byte was just sent
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*I2CCR &= ~I2C_MTX; // switch to receive mode
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dummy = *I2CDR; // dummy read to throw away the address from register
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} else if (rx_byte_ctr > 0) {
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i2c_recv_byte(); // read new byte
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} else {
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*I2CCR &= ~I2C_MSTA; // generate stop condition
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}
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}
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}
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if (*I2CSR & I2C_MAL) {
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*I2CSR &= ~I2C_MAL; // should be cleared in software
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printf("*** ERROR I2C: Arbitration lost\n");
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// Arbitration lost; reset..
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rx_byte_ctr = tx_byte_ctr = 0;
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*I2CCR &= ~I2C_MSTA; // generate stop condition
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}
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// clear MIF
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*I2CSR &= ~I2C_MIF;
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}
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}
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#endif
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