I2C — 主机轮询通信（LL 库）

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#include "main.h"
#include "py32f030xx_ll_Start_Kit.h"

#define I2C_ADDRESS        0xA0     /* 从机地址 */
#define I2C_SPEEDCLOCK     100000   /* 100K 标准速率 */
#define I2C_STATE_READY    0
#define I2C_STATE_BUSY_TX  1
#define I2C_STATE_BUSY_RX  2

uint8_t aTxBuffer[15] = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
uint8_t aRxBuffer[15] = {0};

uint8_t         *pBuffPtr  = NULL;
__IO uint16_t   XferCount  = 0;
__IO uint32_t   Devaddress = 0;
__IO uint32_t   State      = I2C_STATE_READY;

static void APP_SystemClockConfig(void);
static void APP_ConfigI2cMaster(void);
static void APP_MasterTransmit(uint16_t DevAddress, uint8_t *pData, uint16_t Size);
static void APP_MasterReceive(uint16_t DevAddress, uint8_t *pData, uint16_t Size);
static void APP_CheckEndOfTransfer(void);
static uint8_t APP_Buffercmp8(uint8_t* pBuffer1, uint8_t* pBuffer2, uint8_t BufferLength);
static void APP_LedBlinking(void);

int main(void)
{
  APP_SystemClockConfig();
  BSP_LED_Init(LED_GREEN);
  BSP_PB_Init(BUTTON_KEY, BUTTON_MODE_GPIO);

  APP_ConfigI2cMaster();

  while (BSP_PB_GetState(BUTTON_KEY) == 1);   /* 等待按键按下 */

  APP_MasterTransmit(I2C_ADDRESS, (uint8_t *)aTxBuffer, sizeof(aTxBuffer));
  while (State != I2C_STATE_READY);           /* 等发送完 */
  APP_MasterReceive(I2C_ADDRESS, (uint8_t *)aRxBuffer, sizeof(aRxBuffer));
  while (State != I2C_STATE_READY);           /* 等接收完 */

  APP_CheckEndOfTransfer();                   /* 比对结果 */
  while (1) {}
}

/**
  * @brief  I2C 主机 GPIO + 外设配置
  */
static void APP_ConfigI2cMaster(void)
{
  LL_IOP_GRP1_EnableClock(LL_IOP_GRP1_PERIPH_GPIOA);
  LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_I2C1);

  /* SCL=PA9, SDA=PA10：复用、开漏、上拉、AF6 */
  LL_GPIO_InitTypeDef GPIO_InitStruct = {0};
  GPIO_InitStruct.Pin        = LL_GPIO_PIN_9;
  GPIO_InitStruct.Mode       = LL_GPIO_MODE_ALTERNATE;
  GPIO_InitStruct.Speed      = LL_GPIO_SPEED_FREQ_HIGH;
  GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_OPENDRAIN;   /* I2C 必须开漏 */
  GPIO_InitStruct.Pull       = LL_GPIO_PULL_UP;
  GPIO_InitStruct.Alternate  = LL_GPIO_AF_6;
  LL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  GPIO_InitStruct.Pin = LL_GPIO_PIN_10;
  LL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /* 复位 I2C 外设 */
  LL_APB1_GRP1_ForceReset(LL_APB1_GRP1_PERIPH_I2C1);
  LL_APB1_GRP1_ReleaseReset(LL_APB1_GRP1_PERIPH_I2C1);

  LL_I2C_InitTypeDef I2C_InitStruct = {0};
  I2C_InitStruct.ClockSpeed      = I2C_SPEEDCLOCK;
  I2C_InitStruct.DutyCycle       = LL_I2C_DUTYCYCLE_16_9;
  I2C_InitStruct.OwnAddress1     = I2C_ADDRESS;
  I2C_InitStruct.TypeAcknowledge = LL_I2C_NACK;
  LL_I2C_Init(I2C1, &I2C_InitStruct);
}

/**
  * @brief  LL 主机发送：起始→地址→数据→停止，全程轮询标志
  */
static void APP_MasterTransmit(uint16_t DevAddress, uint8_t *pData, uint16_t Size)
{
  pBuffPtr = pData; XferCount = Size; Devaddress = DevAddress;
  State = I2C_STATE_BUSY_TX;

  LL_I2C_GenerateStartCondition(I2C1);
  while (LL_I2C_IsActiveFlag_SB(I2C1) != 1);           /* 等起始条件发送完 */

  LL_I2C_TransmitData8(I2C1, (Devaddress & (uint8_t)(~0x01)));  /* 发写地址(末位0) */
  while (LL_I2C_IsActiveFlag_ADDR(I2C1) != 1);
  LL_I2C_ClearFlag_ADDR(I2C1);                          /* 清地址标志 */

  while (XferCount > 0)
  {
    while (LL_I2C_IsActiveFlag_TXE(I2C1) != 1);         /* 等发送寄存器空 */
    LL_I2C_TransmitData8(I2C1, *pBuffPtr);              /* 发一字节 */
    pBuffPtr++; XferCount--;
    while (LL_I2C_IsActiveFlag_BTF(I2C1) != 1);         /* 等字节发完(BTF) */
  }

  LL_I2C_GenerateStopCondition(I2C1);                   /* 发停止条件 */
  State = I2C_STATE_READY;
}

/**
  * @brief  LL 主机接收：起始→地址(读)→接收 N 字节→停止
  */
static void APP_MasterReceive(uint16_t DevAddress, uint8_t *pData, uint16_t Size)
{
  pBuffPtr = pData; XferCount = Size; Devaddress = DevAddress;
  State = I2C_STATE_BUSY_RX;

  LL_I2C_AcknowledgeNextData(I2C1, LL_I2C_ACK);        /* 先允许 ACK */
  LL_I2C_GenerateStartCondition(I2C1);
  while (LL_I2C_IsActiveFlag_SB(I2C1) != 1);
  LL_I2C_TransmitData8(I2C1, (Devaddress | 0x1));      /* 发读地址(末位1) */
  while (LL_I2C_IsActiveFlag_ADDR(I2C1) != 1);
  LL_I2C_ClearFlag_ADDR(I2C1);

  while (XferCount > 0)
  {
    while (LL_I2C_IsActiveFlag_RXNE(I2C1) != 1);        /* 等收到一字节 */
    *pBuffPtr = LL_I2C_ReceiveData8(I2C1);              /* 读一字节 */
    pBuffPtr++; XferCount--;
  }
  State = I2C_STATE_READY;
}

/* APP_CheckEndOfTransfer / APP_Buffercmp8 / APP_LedBlinking / 时钟与错误处理
   与前述示例同构，略 */