/* * The MIT License (MIT) * * Copyright (c) 2015 Matthias P. Braendli * * 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. */ #include "i2c.h" #include "common.h" #include "stm32f4xx_conf.h" #include "stm32f4xx_i2c.h" #include "stm32f4xx.h" #include "FreeRTOS.h" #include "FreeRTOSConfig.h" #include "task.h" #include "semphr.h" /* I2C 1 on PB9 and PB6 * See pio.txt for PIO allocation details */ const uint16_t GPIOB_PIN_SDA = GPIO_Pin_9; const uint16_t GPIOB_PIN_SCL = GPIO_Pin_6; static int i2c_init_done = 0; static int i2c_error = 0; static I2C_TypeDef* const I2Cx = I2C1; static SemaphoreHandle_t i2c_semaphore; static void i2c_device_init(void); /* According to I2C spec UM10204: * 3.1.16 Bus clear * In the unlikely event where the clock (SCL) is stuck LOW, the preferential * procedure is to reset the bus using the HW reset signal if your I2C devices * have HW reset inputs. If the I2C devices do not have HW reset inputs, cycle * power to the devices to activate the mandatory internal Power-On Reset (POR) * circuit. * * If the data line (SDA) is stuck LOW, the master should send nine clock * pulses. The device that held the bus LOW should release it sometime within * those nine clocks. If not, then use the HW reset or cycle power to clear the * bus. */ static void i2c_recover_from_lockup(void) { I2C_SoftwareResetCmd(I2Cx, ENABLE); // Configure I2C SCL and SDA pins. GPIO_InitTypeDef GPIO_InitStructure; GPIO_InitStructure.GPIO_Pin = GPIOB_PIN_SCL | GPIOB_PIN_SDA; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT; GPIO_InitStructure.GPIO_OType = GPIO_OType_OD; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; GPIO_Init(GPIOB, &GPIO_InitStructure); const TickType_t delay = 5 / portTICK_PERIOD_MS; GPIO_SetBits(GPIOB, GPIOB_PIN_SDA | GPIOB_PIN_SCL); vTaskDelay(delay); for (int i = 0; i < 10; i++) { GPIO_ResetBits(GPIOB, GPIOB_PIN_SCL); vTaskDelay(delay); GPIO_SetBits(GPIOB, GPIOB_PIN_SCL); vTaskDelay(delay); } I2C_SoftwareResetCmd(I2Cx, DISABLE); i2c_device_init(); } static void i2c_device_init(void) { // Configure I2C SCL and SDA pins. GPIO_InitTypeDef GPIO_InitStructure; GPIO_InitStructure.GPIO_Pin = GPIOB_PIN_SCL | GPIOB_PIN_SDA; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; GPIO_InitStructure.GPIO_OType = GPIO_OType_OD; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; GPIO_Init(GPIOB, &GPIO_InitStructure); GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_I2C1); GPIO_PinAFConfig(GPIOB, GPIO_PinSource9, GPIO_AF_I2C1); // Reset I2C. RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, ENABLE); RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, DISABLE); // configure I2C1 I2C_InitTypeDef I2C_InitStruct; I2C_InitStruct.I2C_ClockSpeed = 100000; //Hz I2C_InitStruct.I2C_Mode = I2C_Mode_I2C; I2C_InitStruct.I2C_DutyCycle = I2C_DutyCycle_2; // 50% duty cycle I2C_InitStruct.I2C_OwnAddress1 = 0x00; // not relevant in master mode // disable acknowledge when reading (can be changed later on) I2C_InitStruct.I2C_Ack = I2C_Ack_Disable; I2C_InitStruct.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit; I2C_Init(I2C1, &I2C_InitStruct); // enable I2C1 I2C_Cmd(I2C1, ENABLE); } void i2c_init() { if (i2c_init_done == 1) { return; } i2c_semaphore = xSemaphoreCreateBinary(); if ( i2c_semaphore == NULL ) { trigger_fault(FAULT_SOURCE_I2C); } else { xSemaphoreGive(i2c_semaphore); } RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE); RCC_APB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE); i2c_device_init(); i2c_init_done = 1; } static int i2c_check_busy_flag(void) { const TickType_t i2c_timeout = 1000ul / portTICK_PERIOD_MS; const TickType_t time_start = xTaskGetTickCount(); while (I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY)) { const TickType_t time_now = xTaskGetTickCount(); if (time_now - time_start > i2c_timeout) { i2c_error = 1; return 0; } } return 1; } static int i2c_check_event(uint32_t event) { const TickType_t i2c_timeout = 1000ul / portTICK_PERIOD_MS; const TickType_t time_start = xTaskGetTickCount(); while (!I2C_CheckEvent(I2Cx, event)) { const TickType_t time_now = xTaskGetTickCount(); if (time_now - time_start > i2c_timeout) { i2c_error = 1; return 0; } } return 1; } static int i2c_start(uint8_t device, uint8_t direction) { I2C_GenerateSTART(I2Cx, ENABLE); // wait for bus free if (!i2c_check_event(I2C_EVENT_MASTER_MODE_SELECT)) { I2C_GenerateSTART(I2Cx, DISABLE); return 0; } I2C_Send7bitAddress(I2Cx, device << 1, direction); /* wait for I2C1 EV6, check if * either Slave has acknowledged Master transmitter or * Master receiver mode, depending on the transmission * direction */ uint32_t event = 0; if (direction == I2C_Direction_Transmitter) { event = I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED; } else if (direction == I2C_Direction_Receiver) { event = I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED; } else { trigger_fault(FAULT_SOURCE_I2C); } if (!i2c_check_event(event)) { return 0; } return 1; } static int i2c_send(uint8_t data) { I2C_SendData(I2Cx, data); // wait for I2C1 EV8_2 --> byte has been transmitted return i2c_check_event(I2C_EVENT_MASTER_BYTE_TRANSMITTED); } int i2c_write(uint8_t device, const uint8_t *txbuf, int len) { if (i2c_init_done == 0) { trigger_fault(FAULT_SOURCE_I2C); } int success = i2c_check_busy_flag(); if (success) { success = i2c_start(device, I2C_Direction_Transmitter); } if (success) { for (int i = 0; i < len; i++) { success = i2c_send(txbuf[i]); if (!success) { break; } } I2C_GenerateSTOP(I2Cx, ENABLE); success = i2c_check_event(I2C_EVENT_MASTER_BYTE_TRANSMITTED); } return success; } static int i2c_read_nobuscheck(uint8_t device, uint8_t *rxbuf, int len) { if (i2c_init_done == 0) { trigger_fault(FAULT_SOURCE_I2C); } if (i2c_start(device, I2C_Direction_Receiver)) { for (int i = 0; i < len; i++) { if (i == len-1) { I2C_AcknowledgeConfig(I2Cx, DISABLE); } else { I2C_AcknowledgeConfig(I2Cx, ENABLE); } // wait until one byte has been received, possibly timout if (!i2c_check_event(I2C_EVENT_MASTER_BYTE_RECEIVED)) { I2C_GenerateSTOP(I2Cx, ENABLE); return 0; } if (i == len-1) { I2C_GenerateSTOP(I2Cx, ENABLE); } rxbuf[i] = I2C_ReceiveData(I2Cx); } return len; } return 0; } int i2c_read(uint8_t device, uint8_t *rxbuf, int len) { int success = i2c_check_busy_flag(); if (success) { success = i2c_read_nobuscheck(device, rxbuf, len); } return success; } int i2c_read_from(uint8_t device, uint8_t address, uint8_t *rxbuf, int len) { if (i2c_init_done == 0) { trigger_fault(FAULT_SOURCE_I2C); } int success = i2c_check_busy_flag(); if (success) { success = i2c_start(device, I2C_Direction_Transmitter); } if (success) { success = i2c_send(address); } // Don't do a STOP if (success) { success = i2c_read_nobuscheck(device, rxbuf, len); } return success; } void i2c_transaction_start() { if (i2c_init_done == 0) { trigger_fault(FAULT_SOURCE_I2C); } xSemaphoreTake(i2c_semaphore, portMAX_DELAY); } void i2c_transaction_end() { if (i2c_init_done == 0) { trigger_fault(FAULT_SOURCE_I2C); } if ( i2c_error ) { i2c_recover_from_lockup(); i2c_error = 0; } xSemaphoreGive(i2c_semaphore); }