390 lines
14 KiB
C
390 lines
14 KiB
C
/* 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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/** @brief library to communicate with the Maxim DS1307 I2C RTC IC (code)
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* @file rtc_ds1307.c
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2016
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* @note peripherals used: I2C @ref rtc_ds1307_i2c
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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 <libopencm3/cm3/nvic.h> // interrupt handler
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#include <libopencmsis/core_cm3.h> // Cortex M3 utilities
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#include "global.h" // global utilities
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#include "rtc_ds1307.h" // RTC header and definitions
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/** @defgroup rtc_ds1307_i2c I2C peripheral used to communication with the DS1307 RTC IC
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* @{
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*/
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/** I2C peripheral */
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#define I2C I2C1 /**< I2C peripheral */
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#define I2C_RCC RCC_I2C1 /**< I2C peripheral clock */
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#define I2C_PORT GPIOB /**< I2C peripheral port */
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#define I2C_PIN_SDA GPIO_I2C1_SDA /**< I2C peripheral data pin (PB7) */
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#define I2C_PIN_SCL GPIO_I2C1_SCL /**< I2C peripheral clock pin (PB6) */
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/** @} */
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#define I2C_ADDR 0x68 /**< DS1307 I2C address (fixed to 0b1101000) */
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void rtc_setup(void)
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{
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/* enable peripheral */
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rcc_periph_clock_enable(RCC_AFIO); // enable clock for alternate function
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rcc_periph_clock_enable(I2C_RCC); // enable clock for I2C peripheral
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gpio_set_mode(I2C_PORT, GPIO_MODE_OUTPUT_10_MHZ, GPIO_CNF_OUTPUT_ALTFN_OPENDRAIN, I2C_PIN_SDA | I2C_PIN_SCL); // setup I2C pin
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/* configure I2C peripheral (see RM008 26.3.3, I2C master) */
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i2c_reset(I2C); // reset configuration
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i2c_peripheral_disable(I2C); // I2C needs to be disable to be configured
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i2c_set_clock_frequency(I2C, rcc_apb1_frequency/1E6); // configure the peripheral clock to the APB1 freq (where it is connected to)
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i2c_set_standard_mode(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, rcc_apb1_frequency/(100E3*2)); // set Thigh/Tlow to generate frequency of 100 kHz
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i2c_set_trise(I2C, rcc_apb1_frequency/1E6); // max rise time for 100 kHz is 1000 ns (~1 MHz)
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i2c_peripheral_enable(I2C); // enable I2C after configuration completed
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}
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/** @brief read memory from RTC IC
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* @param[in] addr start address for memory to read
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* @param[out] data buffer to store read memory
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* @param[in] len number of byte to read from the memory
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* @return if read succeeded
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*/
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static bool rtc_read_memory(uint8_t addr, uint8_t* data, size_t len)
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{
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bool to_return = false; // return if read succeeded
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if (data==NULL || len==0) { // verify there it data to be read
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goto error;
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}
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i2c_send_start(I2C); // send start condition to start transaction
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while (!(I2C_SR1(I2C) & I2C_SR1_SB)); // wait until start condition is transmitted
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if (!(I2C_SR2(I2C) & I2C_SR2_MSL)) { // verify if in master mode
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goto error;
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}
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i2c_send_7bit_address(I2C, I2C_ADDR, I2C_WRITE); // select slave
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while (!(I2C_SR1(I2C) & I2C_SR1_ADDR)); // wait until address is transmitted
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if (!((I2C_SR2(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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i2c_send_data(I2C, addr); // send memory address we want to read
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while (!(I2C_SR1(I2C) & I2C_SR1_TxE)); // wait until byte has been transmitted
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i2c_send_start(I2C); // send restart condition to switch from write to read mode
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while (!(I2C_SR1(I2C) & I2C_SR1_SB)); // wait until start condition is transmitted
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i2c_send_7bit_address(I2C, I2C_ADDR, I2C_READ); // select slave
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while (!(I2C_SR1(I2C) & I2C_SR1_ADDR)); // wait until address is transmitted
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if ((I2C_SR2(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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for (size_t i=0; i<len; i++) { // read bytes
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if (i==len-1) { // prepare to sent NACK for last byte
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i2c_disable_ack(I2C); // NACK received to stop slave transmission
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i2c_send_stop(I2C); // send STOP after receiving byte
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} else {
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i2c_enable_ack(I2C); // ACK received byte to continue slave transmission
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}
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while (!(I2C_SR1(I2C) & I2C_SR1_RxNE)); // wait until byte has been received
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data[i] = i2c_get_data(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_SR2_BUSY) { // release bus if busy
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i2c_send_stop(I2C); // send stop to release bus
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}
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while (I2C_SR2(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 rtc_oscillator_disabled(void)
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{
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uint8_t data[1] = {0}; // to read data from I2C
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rtc_read_memory(0, data, LENGTH(data)); // read a single byte containing CH value
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return data[0]&0x80; // return CH bit value to indicate if oscillator is disabled
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}
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uint8_t rtc_read_seconds(void)
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{
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uint8_t to_return = 0; // seconds to return
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uint8_t data[1] = {0}; // to read data from I2C
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rtc_read_memory(0, data, LENGTH(data)); // read a single byte containing seconds value
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to_return = ((data[0]&0x70)>>4)*10+(data[0]&0x0f); // convert BCD coding into seconds
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return to_return;
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}
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uint8_t rtc_read_minutes(void)
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{
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uint8_t to_return = 0; // minutes to return
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uint8_t data[1] = {0}; // to read data from I2C
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rtc_read_memory(1, data, LENGTH(data)); // read a single byte containing minutes value
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to_return = (data[0]>>4)*10+(data[0]&0x0f); // convert BCD coding into minutes
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return to_return;
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}
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uint8_t rtc_read_hours(void)
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{
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uint8_t to_return = 0; // hours to return
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uint8_t data[1] = {0}; // to read data from I2C
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rtc_read_memory(2, data, LENGTH(data)); // read a single byte containing hours value
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if (data[0]&0x40) { // 12 hour mode
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if (data[0]&0x02) { // PM
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to_return += 12; // add the 12 hours
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}
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to_return += ((data[0]&0x10)>>4)*10; // convert BCD coding into hours (first digit)
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} else {
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to_return = ((data[0]&0x30)>>4)*10; // convert BCD coding into hours (first digit)
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}
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to_return += (data[0]&0x0f); // convert BCD coding into hours (second digit)
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return to_return;
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}
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uint8_t rtc_read_day(void)
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{
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uint8_t to_return = 0; // day to return
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uint8_t data[1] = {0}; // to read data from I2C
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rtc_read_memory(3, data, LENGTH(data)); // read a single byte containing day value
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to_return = (data[0]&0x07); // convert BCD coding into days
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return to_return;
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}
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uint8_t rtc_read_date(void)
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{
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uint8_t to_return = 0; // date to return
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uint8_t data[1] = {0}; // to read data from I2C
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rtc_read_memory(4, data, LENGTH(data)); // read a single byte containing date value
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to_return = ((data[0]&0x30)>>4)*10+(data[0]&0x0f); // convert BCD coding into date
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return to_return;
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}
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uint8_t rtc_read_month(void)
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{
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uint8_t to_return = 0; // month to return
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uint8_t data[1] = {0}; // to read data from I2C
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rtc_read_memory(5, data, LENGTH(data)); // read a single byte containing month value
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to_return = ((data[0]&0x10)>>4)*10+(data[0]&0x0f); // convert BCD coding into month
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return to_return;
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}
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uint16_t rtc_read_year(void)
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{
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uint16_t to_return = 2000; // year to return
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uint8_t data[1] = {0}; // to read data from I2C
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rtc_read_memory(6, data, LENGTH(data)); // read a single byte containing year value
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to_return += ((data[0]&0xf0)>>4)*10+(data[0]&0x0f); // convert BCD coding into year
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return to_return;
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}
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uint16_t* rtc_read_time(void)
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{
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static uint16_t time[7] = {0}; // store time {seconds, minutes, hours, day, date, month, year}
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uint8_t data[7] = {0}; // to read data from I2C
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rtc_read_memory(0, data, LENGTH(data)); // read all time bytes
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time[0] = ((data[0]&0x70)>>4)*10+(data[0]&0x0f); // convert seconds from BCD
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time[1] = (data[1]>>4)*10+(data[1]&0x0f); // convert minutes from BCD
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time[2] = 0; // re-initialize hours
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if (data[2]&0x40) { // 12 hour mode
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if (data[2]&0x02) { // PM
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time[2] += 12; // add the 12 hours
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}
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time[2] += ((data[2]&0x10)>>4)*10; // convert BCD coding into hours (first digit)
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} else {
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time[2] = ((data[2]&0x30)>>4)*10; // convert BCD coding into hours (first digit)
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}
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time[2] += (data[2]&0x0f); // convert BCD coding into hours (second digit)
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time[3] = (data[3]&0x07); // convert BCD coding into days
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time[4] = ((data[4]&0x30)>>4)*10+(data[4]&0x0f); // convert BCD coding into date
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time[5] = ((data[5]&0x10)>>4)*10+(data[5]&0x0f); // convert BCD coding into month
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time[6] = 2000+((data[6]&0xf0)>>4)*10+(data[6]&0x0f); // convert BCD coding into year
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return time;
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}
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/** @brief write memory into RTC IC
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* @param[in] addr start address for memory to be written
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* @param[in] data buffer to for memory to be written
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* @param[in] len number of byte to write into the memory
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* @return if write succeeded
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*/
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static bool rtc_write_memory(uint8_t addr, uint8_t* data, size_t len)
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{
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bool to_return = false; // return if read succeeded
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if (data==NULL || len==0) { // verify there it data to be read
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goto error;
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}
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i2c_send_start(I2C); // send start condition to start transaction
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while (!(I2C_SR1(I2C) & I2C_SR1_SB)); // wait until start condition is transmitted
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if (!(I2C_SR2(I2C) & I2C_SR2_MSL)) { // verify if in master mode
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goto error;
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}
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i2c_send_7bit_address(I2C, I2C_ADDR, I2C_WRITE); // select slave
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while (!(I2C_SR1(I2C) & I2C_SR1_ADDR)); // wait until address is transmitted
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if (!((I2C_SR2(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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i2c_send_data(I2C, addr); // send memory address we want to read
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while (!(I2C_SR1(I2C) & I2C_SR1_TxE)); // wait until byte has been transmitted
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for (size_t i=0; i<len; i++) { // write bytes
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i2c_send_data(I2C, data[i]); // send byte to be written in memory
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while (!(I2C_SR1(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_SR2_BUSY) { // release bus if busy
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i2c_send_stop(I2C); // send stop to release bus
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}
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while (I2C_SR2(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 rtc_oscillator_disable(void)
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{
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uint8_t data[1] = {0}; // to read CH value data from I2C
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rtc_read_memory(0, data, LENGTH(data)); // read seconds with CH value
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data[0] |= 0x80; // set CH to disable oscillator
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return rtc_write_memory(0, data, LENGTH(data)); // write current seconds with CH value
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}
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bool rtc_oscillator_enable(void)
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{
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uint8_t data[1] = {0}; // to read CH value data from I2C
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rtc_read_memory(0, data, LENGTH(data)); // read seconds with CH value
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data[0] &= 0x7f; // clear CH to enable oscillator
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return rtc_write_memory(0, data, LENGTH(data)); // write current seconds with CH value
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}
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bool rtc_write_seconds(uint8_t seconds)
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{
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if (seconds>59) {
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return false;
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}
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uint8_t data[1] = {0}; // to read CH value data from I2C
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if (!rtc_read_memory(0, data, LENGTH(data))) { // read seconds with CH value
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return false;
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}
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data[0] &= 0x80; // only keep CH flag
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data[0] |= (((seconds/10)%6)<<4)+(seconds%10); // encode seconds in BCD format
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return rtc_write_memory(0, data, LENGTH(data)); // write current seconds with previous CH value
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}
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bool rtc_write_minutes(uint8_t minutes)
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{
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if (minutes>59) {
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return false;
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}
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uint8_t data[1] = {0}; // to write time value
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data[0] = (((minutes/10)%6)<<4)+(minutes%10); // encode minutes in BCD format
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return rtc_write_memory(1, data, LENGTH(data)); // write time value on RTC
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}
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bool rtc_write_hours(uint8_t hours)
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{
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if (hours>24) {
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return false;
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}
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uint8_t data[1] = {0}; // to write time value
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data[0] = (((hours/10)%3)<<4)+(hours%10); // encode hours in BCD 24h format
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return rtc_write_memory(2, data, LENGTH(data)); // write time value on RTC
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}
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bool rtc_write_day(uint8_t day)
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{
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if (day<1 || day>7) {
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return false;
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}
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uint8_t data[1] = {0}; // to write time value
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data[0] = (day%8); // encode day in BCD format
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return rtc_write_memory(3, data, LENGTH(data)); // write time value on RTC
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}
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bool rtc_write_date(uint8_t date)
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{
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if (date<1 || date>31) {
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return false;
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}
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uint8_t data[1] = {0}; // to write time value
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data[0] = (((date/10)%4)<<4)+(date%10); // encode date in BCD format
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return rtc_write_memory(4, data, LENGTH(data)); // write time value on RTC
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}
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bool rtc_write_month(uint8_t month)
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{
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if (month<1 || month>12) {
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return false;
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}
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uint8_t data[1] = {0}; // to write time value
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data[0] = (((month/10)%2)<<4)+(month%10); // encode month in BCD format
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return rtc_write_memory(5, data, LENGTH(data)); // write time value on RTC
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}
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bool rtc_write_year(uint16_t year)
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{
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if (year<2000 || year>2099) {
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return false;
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}
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uint8_t data[1] = {0}; // to write time value
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data[0] = (((year/10)%10)<<4)+(year%10); // encode year in BCD format
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return rtc_write_memory(6, data, LENGTH(data)); // write time value on RTC
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}
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bool rtc_write_time(uint8_t seconds, uint8_t minutes, uint8_t hours, uint8_t day, uint8_t date, uint8_t month, uint16_t year)
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{
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uint8_t data[7] = {0}; // to write all time values
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// seconds
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if (seconds>59) {
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return false;
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}
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if (!rtc_read_memory(0, data, 1)) { // read seconds with CH value
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return false;
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}
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data[0] &= 0x80; // only keep CH flag
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data[0] |= (((seconds/10)%6)<<4)+(seconds%10); // encode seconds in BCD format
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// minutes
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if (minutes>59) {
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return false;
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}
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data[1] = (((minutes/10)%6)<<4)+(minutes%10); // encode minutes in BCD format
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// hours
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if (hours>24) {
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return false;
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}
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data[2] = (((hours/10)%3)<<4)+(hours%10); // encode hours in BCD 24h format
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// day
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if (day<1 || day>7) {
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return false;
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}
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data[3] = (day%8); // encode day in BCD format
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// date
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if (date<1 || date>31) {
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return false;
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}
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data[4] = (((date/10)%4)<<4)+(date%10); // encode date in BCD format
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// month
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if (month<1 || month>12) {
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return false;
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}
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data[5] = (((month/10)%2)<<4)+(month%10); // encode month in BCD format
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// year
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if (year<2000 || year>2099) {
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return false;
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}
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data[6] = (((year/10)%10)<<4)+(year%10); // encode year in BCD format
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return rtc_write_memory(0, data, LENGTH(data)); // write time values on RTC
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}
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