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/******************************************************************************
* The MIT License
*
* Copyright (c) 2012 LeafLabs, LLC.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*****************************************************************************/
/**
* @file libmaple/stm32f1/i2c.c
* @brief STM32F1 I2C support
*/
#include "i2c_private.h"
#include <libmaple/i2c.h>
/*
* Devices
*/
static i2c_dev i2c1 = I2C_DEV_OLD(1, &gpiob, 7, 6);
static i2c_dev i2c2 = I2C_DEV_OLD(2, &gpiob, 11, 10);
/** STM32F1 I2C device 1 */
i2c_dev* const I2C1 = &i2c1;
/** STM32F1 I2C device 2 */
i2c_dev* const I2C2 = &i2c2;
/*
* Routines
*/
static int i2c1_wants_remap(const i2c_dev *dev) {
/* Check if we've got I2C1 configured for SDA/SCL remap on PB9/PB8 */
return (dev->clk_id == RCC_I2C1) &&
(scl_port(dev)->clk_id == RCC_GPIOB) &&
(sda_port(dev)->clk_id == RCC_GPIOB) &&
(dev->sda_pin == 9) &&
(dev->scl_pin == 8);
}
void i2c_config_gpios(const i2c_dev *dev) {
if (i2c1_wants_remap(dev)) {
afio_remap(AFIO_REMAP_I2C1);
}
gpio_set_mode(sda_port(dev), dev->sda_pin, GPIO_AF_OUTPUT_OD);
gpio_set_mode(scl_port(dev), dev->scl_pin, GPIO_AF_OUTPUT_OD);
}
void i2c_master_release_bus(const i2c_dev *dev) {
gpio_write_bit(scl_port(dev), dev->scl_pin, 1);
gpio_write_bit(sda_port(dev), dev->sda_pin, 1);
gpio_set_mode(scl_port(dev), dev->scl_pin, GPIO_OUTPUT_OD);
gpio_set_mode(sda_port(dev), dev->sda_pin, GPIO_OUTPUT_OD);
}
/*
* IRQ handlers
*/
void __irq_i2c1_ev(void) {
_i2c_irq_handler(I2C1);
}
void __irq_i2c2_ev(void) {
_i2c_irq_handler(I2C2);
}
void __irq_i2c1_er(void) {
_i2c_irq_error_handler(I2C1);
}
void __irq_i2c2_er(void) {
_i2c_irq_error_handler(I2C2);
}
/*
* Internal APIs
*/
void _i2c_irq_priority_fixup(i2c_dev *dev) {
/*
* Important STM32 Errata:
*
* See STM32F10xx8 and STM32F10xxB Errata sheet (Doc ID 14574 Rev 8),
* Section 2.11.1, 2.11.2.
*
* 2.11.1:
* When the EV7, EV7_1, EV6_1, EV6_3, EV2, EV8, and EV3 events are not
* managed before the current byte is being transferred, problems may be
* encountered such as receiving an extra byte, reading the same data twice
* or missing data.
*
* 2.11.2:
* In Master Receiver mode, when closing the communication using
* method 2, the content of the last read data can be corrupted.
*
* If the user software is not able to read the data N-1 before the STOP
* condition is generated on the bus, the content of the shift register
* (data N) will be corrupted. (data N is shifted 1-bit to the left).
*
* ----------------------------------------------------------------------
*
* In order to ensure that events are not missed, the i2c interrupt must
* not be preempted. We set the i2c interrupt priority to be the highest
* interrupt in the system (priority level 0). All other interrupts have
* been initialized to priority level 16. See nvic_init().
*/
nvic_irq_set_priority(dev->ev_nvic_line, 0);
nvic_irq_set_priority(dev->er_nvic_line, 0);
}
void _i2c_set_ccr_trise(i2c_dev *dev, uint32 flags) {
#define I2C_CLK (STM32_PCLK1/1000000)
uint32 ccr = 0;
uint32 trise = 0;
/* I2C1 and I2C2 are fed from APB1, clocked at 36MHz */
i2c_set_input_clk(dev, I2C_CLK);
if (flags & I2C_FAST_MODE) {
ccr |= I2C_CCR_FS;
if (flags & I2C_DUTY_16_9) {
/* Tlow/Thigh = 16/9 */
ccr |= I2C_CCR_DUTY;
ccr |= STM32_PCLK1/(400000 * 25);
} else {
/* Tlow/Thigh = 2 */
ccr |= STM32_PCLK1/(400000 * 3);
}
trise = (300 * (I2C_CLK)/1000) + 1;
} else {
/* Tlow/Thigh = 1 */
ccr = STM32_PCLK1/(100000 * 2);
trise = I2C_CLK + 1;
}
/* Set minimum required value if CCR < 1*/
if ((ccr & I2C_CCR_CCR) == 0) {
ccr |= 0x1;
}
i2c_set_clk_control(dev, ccr);
i2c_set_trise(dev, trise);
}
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