generated from hulk/gd32e23x_template_cmake_vscode
678 lines
24 KiB
C
678 lines
24 KiB
C
//
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// Created by dell on 24-12-20.
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//
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#include "i2c.h"
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/*!
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\brief configure the GPIO ports
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\param[in] none
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\param[out] none
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\retval none
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*/
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void i2c_gpio_config(void) {
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/* enable IIC GPIO clock */
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rcu_periph_clock_enable(RCU_GPIO_I2C);
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/* connect I2C_SCL_PIN to I2C_SCL */
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gpio_af_set(I2C_SCL_PORT, I2C_GPIO_AF, I2C_SCL_PIN);
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/* connect I2C_SDA_PIN to I2C_SDA */
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gpio_af_set(I2C_SDA_PORT, I2C_GPIO_AF, I2C_SDA_PIN);
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/* configure GPIO pins of I2C */
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gpio_mode_set(I2C_SCL_PORT, GPIO_MODE_AF, GPIO_PUPD_PULLUP, I2C_SCL_PIN);
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gpio_output_options_set(I2C_SCL_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, I2C_SCL_PIN);
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gpio_mode_set(I2C_SDA_PORT, GPIO_MODE_AF, GPIO_PUPD_PULLUP, I2C_SDA_PIN);
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gpio_output_options_set(I2C_SDA_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, I2C_SDA_PIN);
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}
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/*!
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\brief configure the I2CX interface
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\param[in] none
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\param[out] none
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\retval none
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*/
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i2c_result_t i2c_config(void) {
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/* configure I2C GPIO */
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i2c_gpio_config();
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/* enable I2C clock */
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rcu_periph_clock_enable(RCU_I2C);
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/* configure I2C clock */
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i2c_clock_config(I2C0, I2C_SPEED, I2C_DTCY_2);
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/* configure I2C address */
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i2c_mode_addr_config(I2C0, I2C_I2CMODE_ENABLE, I2C_ADDFORMAT_7BITS, 0xA0);
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/* enable I2CX */
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i2c_enable(I2C0);
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/* enable acknowledge */
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i2c_ack_config(I2C0, I2C_ACK_ENABLE);
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return I2C_RESULT_SUCCESS;
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}
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/* wait for SCL to go high, return true if successful, false if timeout */
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static bool i2c_wait_scl_high(uint16_t max_wait_time) {
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while (max_wait_time--) {
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if (gpio_input_bit_get(I2C_SCL_PORT, I2C_SCL_PIN)) {
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return true;
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}
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delay_10us(1);
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}
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return false;
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}
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/* generate one manual SCL pulse; return true if SCL observed high (no stuck/overstretch) */
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static bool i2c_generate_scl_pulse(void) {
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GPIO_BC(I2C_SCL_PORT) = I2C_SCL_PIN; /* drive SCL low */
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delay_10us(1);
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GPIO_BOP(I2C_SCL_PORT) = I2C_SCL_PIN; /* release SCL (open-drain -> high via pull-up) */
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return i2c_wait_scl_high(200); /* wait up to ~2ms for clock stretching release */
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}
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/*!
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\brief reset I2C bus
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\param[in] none
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\param[out] none
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\retval none
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*/
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i2c_result_t i2c_bus_reset(void) {
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/* 1. Disable & deinit peripheral so pins can be fully controlled */
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i2c_disable(I2C0);
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i2c_deinit(I2C0);
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#ifdef DEBUG_VERBOSE
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printf("I2C bus reset\r\n");
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#endif
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/* 2. Configure SCL/SDA as GPIO open-drain outputs with pull-up and release them */
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gpio_mode_set(I2C_SCL_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_PULLUP, I2C_SCL_PIN);
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gpio_mode_set(I2C_SDA_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_PULLUP, I2C_SDA_PIN);
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gpio_output_options_set(I2C_SCL_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, I2C_SCL_PIN);
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gpio_output_options_set(I2C_SDA_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, I2C_SDA_PIN);
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gpio_bit_set(I2C_SCL_PORT, I2C_SCL_PIN); /* release SCL */
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gpio_bit_set(I2C_SDA_PORT, I2C_SDA_PIN); /* release SDA */
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#ifdef DEBUG_VERBOSE
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printf("I2C bus reset: SCL = %d, SDA = %d\r\n", gpio_input_bit_get(I2C_SCL_PORT, I2C_SCL_PIN), gpio_input_bit_get(I2C_SDA_PORT, I2C_SDA_PIN));
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#endif
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/* 3. Double sample to confirm bus state */
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delay_10us(1);
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bool scl_value1 = gpio_input_bit_get(I2C_SCL_PORT, I2C_SCL_PIN);
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bool sda_value1 = gpio_input_bit_get(I2C_SDA_PORT, I2C_SDA_PIN);
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delay_10us(1);
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bool scl_value2 = gpio_input_bit_get(I2C_SCL_PORT, I2C_SCL_PIN);
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bool sda_value2 = gpio_input_bit_get(I2C_SDA_PORT, I2C_SDA_PIN);
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/* 4. If SCL low -> stuck (cannot proceed) */
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if (!scl_value2) {
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#ifdef DEBUG_VERBOSE
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printf("I2C bus reset: SCL stuck low\r\n");
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#endif
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return I2C_RECOVERY_SCL_STUCK_LOW;
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}
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/* 5. Fast path: bus idle */
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if (scl_value1 && sda_value1 && scl_value2 && sda_value2) {
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i2c_config();
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#ifdef DEBUG_VERBOSE
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printf("I2C bus reset: bus idle\r\n");
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#endif
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return I2C_RECOVERY_OK;
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}
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/* 6. SDA low: attempt to free by generating up to I2C_RECOVERY_CLOCKS pulses */
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if (scl_value2 && !sda_value2) {
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bool sda_released = false;
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#ifdef DEBUG_VERBOSE
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printf("I2C bus reset: SCL will try to free SDA\r\n");
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#endif
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for (uint8_t i = 0; i < I2C_RECOVERY_CLOCKS && !sda_released; i++) {
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if (!i2c_generate_scl_pulse()) {
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return I2C_RECOVERY_SCL_STUCK_LOW; /* SCL failed to go high */
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}
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if (gpio_input_bit_get(I2C_SDA_PORT, I2C_SDA_PIN)) {
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sda_released = true;
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}
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}
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if (!sda_released) {
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return I2C_RECOVERY_SDA_STUCK_LOW;
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}
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/* 7. Generate a STOP condition to leave bus in idle state */
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#ifdef DEBUG_VERBOSE
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printf("I2C bus reset: generating STOP condition\r\n");
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#endif
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gpio_bit_reset(I2C_SDA_PORT, I2C_SDA_PIN); /* SDA low */
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delay_10us(1);
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gpio_bit_set(I2C_SCL_PORT, I2C_SCL_PIN); /* ensure SCL high */
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delay_10us(1);
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gpio_bit_set(I2C_SDA_PORT, I2C_SDA_PIN); /* SDA rising while SCL high -> STOP */
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delay_10us(1);
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}
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#ifdef DEBUG_VERBOSE
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printf("I2C bus reset: bus recovered\r\n");
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#endif
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/* 8. Reconfigure & enable peripheral */
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i2c_config();
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return I2C_RECOVERY_OK;
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}
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/**
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* @brief 扫描I2C总线，查找连接的设备
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*
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* 该函数会扫描I2C总线上的所有地址（1到126），并尝试与每个地址进行通信。
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* 如果在某个地址上发现了设备，则会打印出该设备的地址。
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* 最后会打印出找到的设备总数。
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*/
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void i2c_scan(void) {
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uint32_t timeout;
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uint8_t address;
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int found_devices = 0;
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// printf("Scanning I2C bus...\r\n");
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const char* msg1 = "Scanning I2C bus...\r\n";
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for (uint8_t i = 0; msg1[i] != '\0'; i++) {
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
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usart_data_transmit(I2C_DEBUG_UART, msg1[i]);
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}
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TC) == RESET) {}
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for (address = 1; address < 127; address++) {
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timeout = 0;
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// 生成起始条件
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while (i2c_flag_get(I2C0, I2C_FLAG_I2CBSY) && (timeout < I2C_TIME_OUT))
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timeout++;
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if (timeout >= I2C_TIME_OUT) {
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continue; // 超时，跳过该地址
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}
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i2c_start_on_bus(I2C0);
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timeout = 0;
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// 等待起始条件发送完成
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while (!i2c_flag_get(I2C0, I2C_FLAG_SBSEND) && (timeout < I2C_TIME_OUT))
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timeout++;
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if (timeout >= I2C_TIME_OUT) {
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continue; // 超时，跳过该地址
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}
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i2c_master_addressing(I2C0, (address << 1), I2C_TRANSMITTER);
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timeout = 0;
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// 等待地址发送完成
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while (!i2c_flag_get(I2C0, I2C_FLAG_ADDSEND) && (timeout < I2C_TIME_OUT))
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timeout++;
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if (timeout < I2C_TIME_OUT) {
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i2c_flag_clear(I2C0, I2C_FLAG_ADDSEND);
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// printf("Found device at 0x%02X\r\n", address);
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const char* msg2_prefix = "Found device at 0x";
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for (uint8_t i = 0; msg2_prefix[i] != '\0'; i++) {
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
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usart_data_transmit(I2C_DEBUG_UART, msg2_prefix[i]);
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}
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// 发送地址的十六进制表示
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uint8_t hex_chars[] = "0123456789ABCDEF";
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
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usart_data_transmit(I2C_DEBUG_UART, hex_chars[(address >> 4) & 0x0F]);
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
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usart_data_transmit(I2C_DEBUG_UART, hex_chars[address & 0x0F]);
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const char* msg2_suffix = "\r\n";
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for (uint8_t i = 0; msg2_suffix[i] != '\0'; i++) {
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
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usart_data_transmit(I2C_DEBUG_UART, msg2_suffix[i]);
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}
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TC) == RESET) {}
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found_devices++;
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}
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// 生成停止条件
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i2c_stop_on_bus(I2C0);
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timeout = 0;
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while (i2c_flag_get(I2C0, I2C_FLAG_STPDET) && (timeout < I2C_TIME_OUT))
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timeout++;
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}
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if (found_devices == 0) {
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// printf("No I2C devices found.\r\n");
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const char* msg3 = "No I2C devices found.\r\n";
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for (uint8_t i = 0; msg3[i] != '\0'; i++) {
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
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usart_data_transmit(I2C_DEBUG_UART, msg3[i]);
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}
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TC) == RESET) {}
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} else {
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// printf("Total %d I2C devices found.\r\n", found_devices);
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const char* msg4_prefix = "Total ";
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for (uint8_t i = 0; msg4_prefix[i] != '\0'; i++) {
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
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usart_data_transmit(I2C_DEBUG_UART, msg4_prefix[i]);
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}
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// 发送设备数量
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if (found_devices >= 10) {
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
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usart_data_transmit(I2C_DEBUG_UART, '0' + (found_devices / 10));
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}
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
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usart_data_transmit(I2C_DEBUG_UART, '0' + (found_devices % 10));
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const char* msg4_suffix = " I2C devices found.\r\n";
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for (uint8_t i = 0; msg4_suffix[i] != '\0'; i++) {
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
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usart_data_transmit(I2C_DEBUG_UART, msg4_suffix[i]);
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}
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while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TC) == RESET) {}
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}
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}
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i2c_result_t i2c_write_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t data[2]) {
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i2c_state_t state = I2C_STATE_START;
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uint16_t timeout = 0;
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uint8_t retry_count = 0;
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/* parameter validation */
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if (data == NULL || slave_addr > 0x7F) {
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return I2C_RESULT_INVALID_PARAM;
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}
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while (retry_count < I2C_MAX_RETRY) {
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switch (state) {
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case I2C_STATE_START:
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timeout = 0;
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/* wait for bus to be idle */
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while (i2c_flag_get(I2C0, I2C_FLAG_I2CBSY) && (timeout < I2C_TIME_OUT)) {
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timeout++;
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}
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if (timeout >= I2C_TIME_OUT) {
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state = I2C_STATE_ERROR;
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break;
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}
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i2c_start_on_bus(I2C0);
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timeout = 0;
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state = I2C_STATE_SEND_ADDRESS;
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break;
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case I2C_STATE_SEND_ADDRESS:
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/* wait for start condition to be sent. SBSEND flag */
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while((!i2c_flag_get(I2C0, I2C_FLAG_SBSEND)) && (timeout < I2C_TIME_OUT)) {
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timeout++;
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}
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if (timeout >= I2C_TIME_OUT) {
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state = I2C_STATE_ERROR;
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break;
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}
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/* send slave address */
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i2c_master_addressing(I2C0, slave_addr << 1, I2C_TRANSMITTER);
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timeout = 0;
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state = I2C_STATE_CLEAR_ADDRESS;
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break;
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case I2C_STATE_CLEAR_ADDRESS:
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/* wait for address to be acknowledged.ADDSEND set means i2c slave sends ACK */
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while ((!i2c_flag_get(I2C0, I2C_FLAG_ADDSEND)) && (!i2c_flag_get(I2C0, I2C_FLAG_AERR)) && (timeout < I2C_TIME_OUT)) {
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timeout++;
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}
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if (timeout >= I2C_TIME_OUT) {
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state = I2C_STATE_ERROR;
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break;
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} else if (i2c_flag_get(I2C0, I2C_FLAG_ADDSEND))
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{
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i2c_flag_clear(I2C0, I2C_FLAG_ADDSEND);
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timeout =0;
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state = I2C_STATE_TRANSMIT_REG;
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break;
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} else {
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i2c_flag_clear(I2C0, I2C_FLAG_AERR);
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timeout =0;
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#ifdef DEBUG_VERBOES
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printf("IIC write failed for Error Slave Address. \n");
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#endif
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return I2C_RESULT_NACK;
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}
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case I2C_STATE_TRANSMIT_REG:
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/* wait until the transmit data buffer is empty */
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while ((!i2c_flag_get(I2C0, I2C_FLAG_TBE)) && (timeout < I2C_TIME_OUT)) {
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timeout++;
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}
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if (timeout >= I2C_TIME_OUT) {
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state = I2C_STATE_ERROR;
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break;
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}
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/* send register address */
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i2c_data_transmit(I2C0, reg_addr);
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timeout = 0;
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state = I2C_STATE_TRANSMIT_DATA;
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break;
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case I2C_STATE_TRANSMIT_DATA:
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/* wait until the transmit data buffer is empty */
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while ((!i2c_flag_get(I2C0, I2C_FLAG_TBE)) && (timeout < I2C_TIME_OUT)) {
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timeout++;
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}
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if (timeout >= I2C_TIME_OUT) {
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state = I2C_STATE_ERROR;
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break;
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}
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/* send register MSB value */
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i2c_data_transmit(I2C0, data[0]);
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timeout = 0;
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/* wait until the transmit data buffer is empty */
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while ((!i2c_flag_get(I2C0, I2C_FLAG_TBE)) && (timeout < I2C_TIME_OUT)) {
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timeout++;
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}
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if (timeout >= I2C_TIME_OUT) {
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state = I2C_STATE_ERROR;
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break;
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}
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if (i2c_flag_get(I2C0, I2C_FLAG_AERR)) {
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i2c_stop_on_bus(I2C0);
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return I2C_RESULT_NACK;
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} else if (i2c_flag_get(I2C0, I2C_FLAG_BERR) || i2c_flag_get(I2C0, I2C_FLAG_LOSTARB)) {
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// 可按需清标志
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i2c_stop_on_bus(I2C0);
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return I2C_RESULT_ERROR;
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}
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/* send register LSB value */
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i2c_data_transmit(I2C0, data[1]);
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timeout = 0;
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/* wait until BTC bit is set */
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while (!i2c_flag_get(I2C0, I2C_FLAG_BTC) && (timeout < I2C_TIME_OUT)) {
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timeout++;
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}
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if (timeout >= I2C_TIME_OUT) {
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state = I2C_STATE_ERROR;
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break;
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}
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state = I2C_STATE_STOP;
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break;
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case I2C_STATE_STOP:
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/* send a stop condition to I2C bus */
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i2c_stop_on_bus(I2C0);
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timeout = 0;
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while ((I2C_CTL0(I2C0) & I2C_CTL0_STOP) && (timeout < I2C_TIME_OUT)) {
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timeout++;
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}
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if (timeout >= I2C_TIME_OUT) {
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state = I2C_STATE_ERROR;
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break;
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}
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/* i2c master sends STOP signal successfully */
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/* success */
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return I2C_RESULT_SUCCESS;
|
||
|
||
case I2C_STATE_ERROR:
|
||
/* send a stop condition to I2C bus */
|
||
i2c_stop_on_bus(I2C0);
|
||
|
||
timeout = 0;
|
||
while ((I2C_CTL0(I2C0) & I2C_CTL0_STOP) && (timeout < I2C_TIME_OUT)) {
|
||
timeout++;
|
||
}
|
||
if (timeout >= I2C_TIME_OUT) {
|
||
return I2C_RESULT_ERROR;
|
||
}
|
||
|
||
i2c_flag_clear(I2C0, I2C_FLAG_AERR);
|
||
i2c_flag_clear(I2C0, I2C_FLAG_BERR);
|
||
i2c_flag_clear(I2C0, I2C_FLAG_LOSTARB);
|
||
|
||
retry_count ++;
|
||
if (retry_count >= I2C_MAX_RETRY)
|
||
{
|
||
#ifdef DEBUG_VERBOES
|
||
printf("IIC write failed after %d retries\n", I2C_MAX_RETRY);
|
||
#endif
|
||
return I2C_RESULT_ERROR;
|
||
}
|
||
|
||
/* reset state machine for retry */
|
||
state = I2C_STATE_START;
|
||
timeout = 0;
|
||
|
||
/* small delay before retry */
|
||
delay_10us(10);
|
||
break;
|
||
|
||
default:
|
||
state = I2C_STATE_START;
|
||
break;
|
||
}
|
||
}
|
||
return I2C_RESULT_TIMEOUT;
|
||
}
|
||
|
||
i2c_result_t i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data) {
|
||
i2c_state_t state = I2C_STATE_START;
|
||
uint16_t timeout = 0;
|
||
uint8_t retry_count = 0;
|
||
bool write_phase = true;
|
||
|
||
// 参数检查：防止空指针和非法地址
|
||
if (data == NULL || slave_addr > 0x7F) {
|
||
return I2C_RESULT_INVALID_PARAM;
|
||
}
|
||
|
||
/* enable acknowledge */
|
||
i2c_ack_config(I2C0, I2C_ACK_ENABLE);
|
||
|
||
while (retry_count < (uint8_t)I2C_MAX_RETRY) {
|
||
switch (state) {
|
||
case I2C_STATE_START:
|
||
timeout = 0;
|
||
|
||
// wait for bus to be idle
|
||
while (i2c_flag_get(I2C0, I2C_FLAG_I2CBSY) && (timeout < I2C_TIME_OUT)) {
|
||
timeout++;
|
||
}
|
||
if (timeout >= I2C_TIME_OUT) {
|
||
state = I2C_STATE_ERROR;
|
||
break;
|
||
}
|
||
|
||
// send start condition
|
||
i2c_start_on_bus(I2C0);
|
||
state = I2C_STATE_SEND_ADDRESS;
|
||
timeout = 0;
|
||
break;
|
||
|
||
case I2C_STATE_SEND_ADDRESS:
|
||
/* wait for start condition to be sent */
|
||
while ((!i2c_flag_get(I2C0, I2C_FLAG_SBSEND)) && (timeout < I2C_TIME_OUT)) {
|
||
timeout++;
|
||
}
|
||
if (timeout >= I2C_TIME_OUT) {
|
||
state = I2C_STATE_ERROR;
|
||
break;
|
||
}
|
||
|
||
// send slave address
|
||
if (write_phase) {
|
||
/* write phase: send address with write bit */
|
||
i2c_master_addressing(I2C0, (slave_addr << 1), I2C_TRANSMITTER);
|
||
} else {
|
||
/* read phase: send address with read bit */
|
||
i2c_master_addressing(I2C0, (slave_addr << 1) | 0x01, I2C_RECEIVER);
|
||
}
|
||
|
||
state = I2C_STATE_CLEAR_ADDRESS;
|
||
timeout = 0;
|
||
break;
|
||
|
||
case I2C_STATE_CLEAR_ADDRESS:
|
||
/* wait for address to be acknowledged */
|
||
while ((!i2c_flag_get(I2C0, I2C_FLAG_ADDSEND)) && (timeout < I2C_TIME_OUT)) {
|
||
timeout++;
|
||
}
|
||
if (timeout >= I2C_TIME_OUT) {
|
||
state = I2C_STATE_ERROR;
|
||
break;
|
||
}
|
||
|
||
if (write_phase) {
|
||
/* clear address flag (write phase) */
|
||
i2c_flag_clear(I2C0, I2C_FLAG_ADDSEND);
|
||
state = I2C_STATE_TRANSMIT_DATA;
|
||
} else {
|
||
/* READ phase for 2 bytes: set POS=NEXT and disable ACK BEFORE clearing ADDR */
|
||
i2c_ackpos_config(I2C0, I2C_ACKPOS_NEXT);
|
||
i2c_ack_config(I2C0, I2C_ACK_DISABLE);
|
||
|
||
/* now clear address flag to release SCL and enter data phase */
|
||
i2c_flag_clear(I2C0, I2C_FLAG_ADDSEND);
|
||
|
||
state = I2C_STATE_RECEIVE_DATA;
|
||
}
|
||
|
||
timeout = 0;
|
||
break;
|
||
|
||
case I2C_STATE_TRANSMIT_DATA:
|
||
/* wait for transmit buffer to be empty */
|
||
while ((!i2c_flag_get(I2C0, I2C_FLAG_TBE)) && (timeout < I2C_TIME_OUT)) {
|
||
timeout++;
|
||
}
|
||
if (timeout >= I2C_TIME_OUT) {
|
||
state = I2C_STATE_ERROR;
|
||
break;
|
||
}
|
||
|
||
/* send register address */
|
||
i2c_data_transmit(I2C0, reg_addr);
|
||
state = I2C_STATE_RESTART;
|
||
timeout = 0;
|
||
break;
|
||
|
||
case I2C_STATE_RESTART:
|
||
/* wait for byte transfer complete BTC: Bit Transfer Complete */
|
||
while ((!i2c_flag_get(I2C0, I2C_FLAG_BTC)) && (timeout < I2C_TIME_OUT)) {
|
||
timeout++;
|
||
}
|
||
if (timeout >= I2C_TIME_OUT) {
|
||
state = I2C_STATE_ERROR;
|
||
break;
|
||
}
|
||
|
||
/* generate repeated start condition */
|
||
i2c_start_on_bus(I2C0);
|
||
|
||
/* wait for repeated start condition to be sent */
|
||
timeout = 0;
|
||
while ((!i2c_flag_get(I2C0, I2C_FLAG_SBSEND)) && (timeout < I2C_TIME_OUT)) {
|
||
timeout++;
|
||
}
|
||
if (timeout >= I2C_TIME_OUT) {
|
||
state = I2C_STATE_ERROR;
|
||
break;
|
||
}
|
||
|
||
/* send slave address with read bit (R/W bit is set by library) */
|
||
i2c_master_addressing(I2C0, (slave_addr << 1), I2C_RECEIVER);
|
||
|
||
/* switch to read phase */
|
||
write_phase = false;
|
||
state = I2C_STATE_CLEAR_ADDRESS;
|
||
timeout = 0;
|
||
break;
|
||
|
||
case I2C_STATE_RECEIVE_DATA:
|
||
/* Wait for BTC (both bytes received) */
|
||
while ((!i2c_flag_get(I2C0, I2C_FLAG_BTC)) && (timeout < I2C_TIME_OUT)) {
|
||
timeout++;
|
||
}
|
||
if (timeout >= I2C_TIME_OUT) {
|
||
state = I2C_STATE_ERROR;
|
||
break;
|
||
}
|
||
|
||
/* Send STOP before reading the last two bytes */
|
||
i2c_stop_on_bus(I2C0);
|
||
|
||
/* Read the two bytes back-to-back */
|
||
data[0] = i2c_data_receive(I2C0);
|
||
data[1] = i2c_data_receive(I2C0);
|
||
|
||
state = I2C_STATE_STOP;
|
||
break;
|
||
|
||
case I2C_STATE_STOP:
|
||
/* wait for stop condition to complete */
|
||
while ((I2C_CTL0(I2C0) & I2C_CTL0_STOP) && (timeout < I2C_TIME_OUT)) {
|
||
timeout++;
|
||
}
|
||
if (timeout >= I2C_TIME_OUT) {
|
||
state = I2C_STATE_ERROR;
|
||
break;
|
||
}
|
||
|
||
/* i2c master sends STOP signal successfully */
|
||
/* success */
|
||
return I2C_RESULT_SUCCESS;
|
||
|
||
case I2C_STATE_ERROR:
|
||
/* send stop condition to release bus */
|
||
i2c_stop_on_bus(I2C0);
|
||
|
||
retry_count++;
|
||
if (retry_count >= I2C_MAX_RETRY) {
|
||
#ifdef DEBUG_VERBOES
|
||
printf("IIC read failed after %d retries\n", I2C_RETRY_MAX);
|
||
#endif
|
||
return I2C_RESULT_ERROR;
|
||
}
|
||
|
||
/* reset state machine for retry */
|
||
state = I2C_STATE_START;
|
||
write_phase = true;
|
||
timeout = 0;
|
||
|
||
/* small delay before retry */
|
||
delay_10us(10);
|
||
break;
|
||
|
||
default:
|
||
state = I2C_STATE_START;
|
||
break;
|
||
}
|
||
}
|
||
return I2C_RESULT_TIMEOUT;
|
||
}
|
||
|
||
#ifdef DEBUG_VERBOSE
|
||
/*!
|
||
\brief get status string for debugging
|
||
\param[in] status: i2c_status_t value
|
||
\param[out] none
|
||
\retval const char* status string
|
||
*/
|
||
const char* i2c_get_status_string(i2c_result_t status) {
|
||
switch (status) {
|
||
case I2C_RESULT_SUCCESS:
|
||
return "SUCCESS";
|
||
case I2C_RESULT_TIMEOUT:
|
||
return "TIMEOUT";
|
||
case I2C_RESULT_NACK:
|
||
return "NACK";
|
||
case I2C_RESULT_BUS_BUSY:
|
||
return "BUS_BUSY";
|
||
case I2C_RESULT_ERROR:
|
||
return "ERROR";
|
||
case I2C_RESULT_INVALID_PARAM:
|
||
return "INVALID_PARAM";
|
||
default:
|
||
return "UNKNOWN";
|
||
}
|
||
}
|
||
#endif
|