I2C: add frequency support instead of just fast mode
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944379fda9
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6e160c31af
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@ -21,7 +21,6 @@
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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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@ -61,6 +60,7 @@ static uint32_t RCC_I2C(uint32_t i2c)
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while (true);
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}
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}
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/** get RCC for GPIO port for SCL pin based on I2C identifier
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* @param[in] i2c I2C base address
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* @return RCC GPIO address
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@ -76,6 +76,7 @@ static uint32_t RCC_GPIO_PORT_SCL(uint32_t i2c)
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while (true);
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}
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}
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/** get RCC for GPIO port for SDA pin based on I2C identifier
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* @param[in] i2c I2C base address
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* @return RCC GPIO address
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@ -91,6 +92,7 @@ static uint32_t RCC_GPIO_PORT_SDA(uint32_t i2c)
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while (true);
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}
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}
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/** get GPIO port for SCL pin based on I2C identifier
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* @param[in] i2c I2C base address
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* @return GPIO address
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@ -112,6 +114,7 @@ static uint32_t GPIO_PORT_SCL(uint32_t i2c)
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while (true);
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}
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}
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/** get GPIO port for SDA pin based on I2C identifier
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* @param[in] i2c I2C base address
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* @return GPIO address
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@ -133,6 +136,7 @@ static uint32_t GPIO_PORT_SDA(uint32_t i2c)
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while (true);
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}
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}
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/** get GPIO pin for SCL pin based on I2C identifier
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* @param[in] i2c I2C base address
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* @return GPIO address
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@ -154,6 +158,7 @@ static uint32_t GPIO_PIN_SCL(uint32_t i2c)
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while (true);
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}
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}
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/** get GPIO pin for SDA pin based on I2C identifier
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* @param[in] i2c I2C base address
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* @return GPIO address
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@ -176,7 +181,7 @@ static uint32_t GPIO_PIN_SDA(uint32_t i2c)
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}
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}
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void i2c_master_setup(uint32_t i2c, bool fast)
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void i2c_master_setup(uint32_t i2c, uint16_t frequency)
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{
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// check I2C peripheral
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if (I2C1!=i2c && I2C2!=i2c) {
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@ -194,15 +199,18 @@ void i2c_master_setup(uint32_t i2c, bool fast)
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rcc_periph_clock_enable(RCC_I2C(i2c)); // enable clock for I2C peripheral
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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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if (frequency>400) { // limit frequency to 400 kHz
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frequency = 400;
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}
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i2c_set_clock_frequency(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);
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i2c_set_ccr(i2c, rcc_apb1_frequency/(400000*2)); // set Thigh/Tlow to generate frequency of 400 kHz
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i2c_set_trise(i2c, (300/(1000/(rcc_apb1_frequency/1000000)))+1); // max rise time for 300 kHz is 300 ns
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if (frequency>100) { // use fast mode for frequencies > 100 kHz
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i2c_set_fast_mode(i2c); // set fast mode
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i2c_set_ccr(i2c, rcc_apb1_frequency/(frequency*1000*2)); // set Thigh/Tlow to generate frequency (fast duty not used)
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i2c_set_trise(i2c, (300/(1000/(rcc_apb1_frequency/1000000)))+1); // max rise time for Fm mode (< 400) kHz is 300 ns
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} else {
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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/(100000*2)); // set Thigh/Tlow to generate frequency of 100 kHz
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i2c_set_trise(i2c, (1000/(1000/(rcc_apb1_frequency/1000000)))+1); // max rise time for 100 kHz is 1000 ns (~1 MHz)
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i2c_set_ccr(i2c, rcc_apb1_frequency/(frequency*1000*2)); // set Thigh/Tlow to generate frequency of 100 kHz
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i2c_set_trise(i2c, (1000/(1000/(rcc_apb1_frequency/1000000)))+1); // max rise time for Sm mode (< 100 kHz) is 1000 ns (~1 MHz)
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}
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i2c_peripheral_enable(i2c); // enable I2C after configuration completed
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@ -212,11 +220,7 @@ void i2c_master_setup(uint32_t i2c, bool fast)
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timer_reset(TIM(I2C_MASTER_TIMER)); // reset timer state
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timer_set_mode(TIM(I2C_MASTER_TIMER), TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); // set timer mode, use undivided timer clock, edge alignment (simple count), and count up
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timer_one_shot_mode(TIM(I2C_MASTER_TIMER)); // stop counter after update event (we only need to one timeout and reset before next operation)
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if (fast) {
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timer_set_prescaler(TIM(I2C_MASTER_TIMER), rcc_ahb_frequency/400000-1); // set the prescaler so one tick is also one I2C bit (used I2C frequency)
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} else {
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timer_set_prescaler(TIM(I2C_MASTER_TIMER), rcc_ahb_frequency/100000-1); // set the prescaler so one tick is also one I2C bit (used I2C frequency)
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}
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timer_set_prescaler(TIM(I2C_MASTER_TIMER), rcc_ahb_frequency/(frequency*1000)-1); // set the prescaler so one tick is also one I2C bit (used I2C frequency)
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timer_set_period(TIM(I2C_MASTER_TIMER), I2C_MASTER_TIMEOUT*9); // use factor to wait for all 9 bits to be transmitted
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timer_update_on_overflow(TIM(I2C_MASTER_TIMER)); // only use counter overflow as UEV source (use overflow as timeout)
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@ -239,6 +243,11 @@ void i2c_master_setup(uint32_t i2c, bool fast)
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void i2c_master_release(uint32_t i2c)
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{
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// check I2C peripheral
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if (I2C1!=i2c && I2C2!=i2c) {
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while (true);
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}
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i2c_reset(i2c); // reset I2C peripheral configuration
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i2c_peripheral_disable(i2c); // disable I2C peripheral
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rcc_periph_clock_disable(RCC_I2C(i2c)); // disable clock for I2C peripheral
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@ -259,6 +268,11 @@ void i2c_master_release(uint32_t i2c)
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bool i2c_master_check_signals(uint32_t i2c)
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{
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// check I2C peripheral
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if (I2C1!=i2c && I2C2!=i2c) {
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while (true);
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}
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return (0!=gpio_get(GPIO_PORT_SCL(i2c), GPIO_PIN_SCL(i2c)) && 0!=gpio_get(GPIO_PORT_SDA(i2c), GPIO_PIN_SDA(i2c)));
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}
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@ -300,7 +314,7 @@ bool i2c_master_select_slave(uint32_t i2c, uint8_t slave, bool write)
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return false; // could not send start condition
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}
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}
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if (!(I2C_SR2(i2c) & I2C_SR2_MSL)) { // I2C device is already not master mode
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if (!(I2C_SR2(i2c) & I2C_SR2_MSL)) { // I2C device is not in master mode
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return false;
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}
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@ -23,9 +23,10 @@
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/** setup I2C peripheral
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* @param[in] i2c I2C base address
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* @param[in] fast use standard (100 kHz) or fast (400 kHz) mode
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* @param[in] frequency frequency to use in kHz (1-400)
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* @note Standard mode (Sm) is used for frequencies up to 100 kHz, and Fast mode (Fm) is used for frequencies up to 400 kHz
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*/
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void i2c_master_setup(uint32_t i2c, bool fast);
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void i2c_master_setup(uint32_t i2c, uint16_t frequency);
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/** release I2C peripheral
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* @param[in] i2c I2C base address
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*/
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