add general I2C library
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/* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/** library to communicate using I2C (code)
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* @file i2c.h
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2017
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* @note peripherals used: I2C @ref i2c_i2c, timer @i2c_timer
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*/
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/* standard libraries */
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#include <stdint.h> // standard integer types
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#include <stdio.h> // standard I/O facilities
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#include <stdlib.h> // general utilities
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/* STM32 (including CM3) libraries */
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#include <libopencm3/stm32/rcc.h> // real-time control clock library
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#include <libopencm3/stm32/gpio.h> // general purpose input output library
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#include <libopencm3/stm32/i2c.h> // I2C library
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#include "global.h" // global utilities
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#include "i2c.h" // I2C header and definitions
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/** @defgroup i2c_i2c I2C peripheral used to communicate
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* @{
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*/
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#define I2C_I2C 2 /**< I2C peripheral */
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/** @} */
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void i2c_master(bool fast)
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{
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// configure I2C peripheral
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rcc_periph_clock_enable(RCC_I2C_SCL_PORT(I2C_I2C)); // enable clock for I2C I/O peripheral
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gpio_set_mode(I2C_SCL_PORT(I2C_I2C), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_ALTFN_OPENDRAIN, I2C_SCL_PIN(I2C_I2C)); // setup I2C I/O pins
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rcc_periph_clock_enable(RCC_I2C_SCL_PORT(I2C_I2C)); // enable clock for I2C I/O peripheral
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gpio_set_mode(I2C_SDA_PORT(I2C_I2C), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_ALTFN_OPENDRAIN, I2C_SDA_PIN(I2C_I2C)); // setup I2C I/O pins
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rcc_periph_clock_enable(RCC_AFIO); // enable clock for alternate function
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rcc_periph_clock_enable(RCC_I2C(I2C_I2C)); // enable clock for I2C peripheral
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i2c_reset(I2C(I2C_I2C)); // reset configuration
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i2c_peripheral_disable(I2C(I2C_I2C)); // I2C needs to be disable to be configured
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i2c_set_clock_frequency(I2C(I2C_I2C), rcc_apb1_frequency/1000000); // configure the peripheral clock to the APB1 freq (where it is connected to)
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if (fast) {
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i2c_set_fast_mode(I2C(I2C_I2C));
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i2c_set_ccr(I2C(I2C_I2C), rcc_apb1_frequency/(400000*2)); // set Thigh/Tlow to generate frequency of 400 kHz
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i2c_set_trise(I2C(I2C_I2C), (300/(1000/(rcc_apb1_frequency/1000000)))+1); // max rise time for 300 kHz is 300 ns
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} else {
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i2c_set_standard_mode(I2C(I2C_I2C)); // the DS1307 has a maximum I2C SCL freq if 100 kHz (corresponding to the standard mode)
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i2c_set_ccr(I2C(I2C_I2C), rcc_apb1_frequency/(100000*2)); // set Thigh/Tlow to generate frequency of 100 kHz
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i2c_set_trise(I2C(I2C_I2C), (1000/(1000/(rcc_apb1_frequency/1000000)))+1); // max rise time for 100 kHz is 1000 ns (~1 MHz)
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}
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i2c_peripheral_enable(I2C(I2C_I2C)); // enable I2C after configuration completed
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}
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bool i2c_read(uint8_t slave, const uint8_t* address, size_t address_size, uint8_t* data, size_t data_size)
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{
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// sanity check
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if (address==NULL || address_size==0 || data==NULL || data_size==0) {
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return false;
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}
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bool to_return = false; // return if read succeeded
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// send start condition
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i2c_send_start(I2C(I2C_I2C)); // send start condition to start transaction
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while (!(I2C_SR1(I2C(I2C_I2C)) & I2C_SR1_SB)); // wait until start condition is transmitted
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if (!(I2C_SR2(I2C(I2C_I2C)) & I2C_SR2_MSL)) { // verify if in master mode
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goto error;
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}
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// select slave
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i2c_send_7bit_address(I2C(I2C_I2C), slave, I2C_WRITE); // select slave
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while (!(I2C_SR1(I2C(I2C_I2C)) & I2C_SR1_ADDR)); // wait until address is transmitted
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if (!((I2C_SR2(I2C(I2C_I2C)) & I2C_SR2_TRA))) { // verify we are in transmit mode (and read SR2 to clear ADDR)
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goto error;
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}
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// send address
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for (size_t i=0; i<address_size; i++) {
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i2c_send_data(I2C(I2C_I2C), address[i]); // send memory address we want to read
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while (!(I2C_SR1(I2C(I2C_I2C)) & I2C_SR1_TxE)); // wait until byte has been transmitted
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}
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// switch to read mode
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i2c_send_start(I2C(I2C_I2C)); // send restart condition to switch from write to read mode
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while (!(I2C_SR1(I2C(I2C_I2C)) & I2C_SR1_SB)); // wait until start condition is transmitted
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i2c_send_7bit_address(I2C(I2C_I2C), slave, I2C_READ); // select slave
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while (!(I2C_SR1(I2C(I2C_I2C)) & I2C_SR1_ADDR)); // wait until address is transmitted
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if ((I2C_SR2(I2C(I2C_I2C)) & I2C_SR2_TRA)) { // verify we are in read mode (and read SR2 to clear ADDR)
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goto error;
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}
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// read data
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for (size_t i=0; i<data_size; i++) { // read bytes
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if (i==data_size-1) { // prepare to sent NACK for last byte
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i2c_disable_ack(I2C(I2C_I2C)); // NACK received to stop slave transmission
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i2c_send_stop(I2C(I2C_I2C)); // send STOP after receiving byte
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} else {
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i2c_enable_ack(I2C(I2C_I2C)); // ACK received byte to continue slave transmission
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}
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while (!(I2C_SR1(I2C(I2C_I2C)) & I2C_SR1_RxNE)); // wait until byte has been received
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data[i] = i2c_get_data(I2C(I2C_I2C)); // read received byte
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}
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to_return = true;
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error:
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if (I2C_SR2(I2C(I2C_I2C)) & I2C_SR2_BUSY) { // release bus if busy
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i2c_send_stop(I2C(I2C_I2C)); // send stop to release bus
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}
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while (I2C_SR2(I2C(I2C_I2C)) & I2C_SR2_MSL); // wait until bus released (non master mode)
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return to_return;
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}
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bool i2c_write(uint8_t slave, const uint8_t* address, size_t address_size, const uint8_t* data, size_t data_size)
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{
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// sanity check
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if (address==NULL || address_size==0 || data==NULL || data_size==0) {
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return false;
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}
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bool to_return = false; // return if read succeeded
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// send start condition
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i2c_send_start(I2C(I2C_I2C)); // send start condition to start transaction
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while (!(I2C_SR1(I2C(I2C_I2C)) & I2C_SR1_SB)); // wait until start condition is transmitted
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if (!(I2C_SR2(I2C(I2C_I2C)) & I2C_SR2_MSL)) { // verify if in master mode
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goto error;
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}
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// select slave
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i2c_send_7bit_address(I2C(I2C_I2C), slave, I2C_WRITE); // select slave
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while (!(I2C_SR1(I2C(I2C_I2C)) & I2C_SR1_ADDR)); // wait until address is transmitted
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if (!((I2C_SR2(I2C(I2C_I2C)) & I2C_SR2_TRA))) { // verify we are in transmit mode (and read SR2 to clear ADDR)
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goto error;
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}
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// send address
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for (size_t i=0; i<address_size; i++) {
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i2c_send_data(I2C(I2C_I2C), address[i]); // send memory address we want to read
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while (!(I2C_SR1(I2C(I2C_I2C)) & I2C_SR1_TxE)); // wait until byte has been transmitted
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}
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// write data
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for (size_t i=0; i<data_size; i++) { // write bytes
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i2c_send_data(I2C(I2C_I2C), data[i]); // send byte to be written in memory
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while (!(I2C_SR1(I2C(I2C_I2C)) & I2C_SR1_TxE)); // wait until byte has been transmitted
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}
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to_return = true;
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error:
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if (I2C_SR2(I2C(I2C_I2C)) & I2C_SR2_BUSY) { // release bus if busy
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i2c_send_stop(I2C(I2C_I2C)); // send stop to release bus
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}
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while (I2C_SR2(I2C(I2C_I2C)) & I2C_SR2_MSL); // wait until bus released (non master mode)
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return to_return;
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}
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@ -0,0 +1,45 @@
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/* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/** library to communicate using I2C (API)
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* @file i2c.h
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2017
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* @note peripherals used: I2C @ref i2c_i2c, timer @i2c_timer
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*/
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#pragma once
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/** setup I2C peripheral
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* @param[in] fast use standard (100 kHz) or fast (400 kHz) mode
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*/
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void i2c_master(bool fast);
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/** read from I2C slave
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* @param[in] slave 7-bit I2C salve device address to read from
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* @param[in] address memory address of slave to read from
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* @param[in] address_size address size in bytes
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* @param[out] data array to store bytes read
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* @pramr[in] data_size number of bytes to read
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* @return if read succeeded
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*/
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bool i2c_read(uint8_t slave, const uint8_t* address, size_t address_size, uint8_t* data, size_t data_size);
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/** write to I2C slave
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* @param[in] slave 7-bit I2C salve device address to write to
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* @param[in] address memory address of slave to write to
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* @param[in] address_size address size in bytes
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* @param[in] data array of byte to write to slave
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* @pramr[in] data_size number of bytes to write
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* @return if write succeeded
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*/
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bool i2c_write(uint8_t slave, const uint8_t* address, size_t address_size, const uint8_t* data, size_t data_size);
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