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在RT1064芯片使用中，遇到LPI2C总线异常，同样代码在RT1062上没问题，LPI2C引脚：
如LPI2C配置。
代码就拿的SDK例程代码：
/*
* Copyright 2017 NXP
* All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
/* Standard C Included Files */
#include <stdio.h>
#include <string.h>
#include "pin_mux.h"
#include "clock_config.h"
#include "board.h"
#include "fsl_debug_console.h"
#include "fsl_lpi2c.h"
/*******************************************************************************
* Definitions
******************************************************************************/
#define EXAMPLE_I2C_MASTER_BASE (LPI2C3_BASE)
/* Select USB1 PLL (480 MHz) as master lpi2c clock source */
#define LPI2C_CLOCK_SOURCE_SELECT (0U)
/* Clock divider for master lpi2c clock source */
#define LPI2C_CLOCK_SOURCE_DIVIDER (5U)
/* Get frequency of lpi2c clock */
#define LPI2C_CLOCK_FREQUENCY ((CLOCK_GetFreq(kCLOCK_Usb1PllClk) / 8) / (LPI2C_CLOCK_SOURCE_DIVIDER + 1U))
#define LPI2C_MASTER_CLOCK_FREQUENCY LPI2C_CLOCK_FREQUENCY
#define WAIT_TIME 10U
#define EXAMPLE_I2C_MASTER ((LPI2C_Type *)EXAMPLE_I2C_MASTER_BASE)
#define LPI2C_MASTER_SLAVE_ADDR_7BIT 0x7EU
#define LPI2C_BAUDRATE 100000U
#define LPI2C_DATA_LENGTH 33U
/*******************************************************************************
* Prototypes
******************************************************************************/
/*******************************************************************************
* Variables
******************************************************************************/
uint8_t g_master_txBuff[LPI2C_DATA_LENGTH];
uint8_t g_master_rxBuff[LPI2C_DATA_LENGTH];
/*******************************************************************************
* Code
******************************************************************************/
/*!
* @brief Main function
*/
int lpi2c_test(void)
{
lpi2c_master_config_t masterConfig;
status_t reVal = kStatus_Fail;
uint8_t deviceAddress = 0x01U;
size_t txCount = 0xFFU;
/*Clock setting for LPI2C*/
CLOCK_SetMux(kCLOCK_Lpi2cMux, LPI2C_CLOCK_SOURCE_SELECT);
CLOCK_SetDiv(kCLOCK_Lpi2cDiv, LPI2C_CLOCK_SOURCE_DIVIDER);
PRINTF("\r\nLPI2C board2board polling example -- Master transfer.\r\n");
/* Set up i2c master to send data to slave*/
/* First data in txBuff is data length of the transmiting data. */
g_master_txBuff[0] = LPI2C_DATA_LENGTH - 1U;
for (uint32_t i = 1U; i < LPI2C_DATA_LENGTH; i++)
{
g_master_txBuff[i] = i - 1;
}
PRINTF("Master will send data :");
for (uint32_t i = 0U; i < LPI2C_DATA_LENGTH - 1U; i++)
{
if (i % 8 == 0)
{
PRINTF("\r\n");
}
PRINTF("0x%2x ", g_master_txBuff[i + 1]);
}
PRINTF("\r\n\r\n");
/*
* masterConfig.debugEnable = false;
* masterConfig.ignoreAck = false;
* masterConfig.pinConfig = kLPI2C_2PinOpenDrain;
* masterConfig.baudRate_Hz = 100000U;
* masterConfig.busIdleTimeout_ns = 0;
* masterConfig.pinLowTimeout_ns = 0;
* masterConfig.sdaGlitchFilterWidth_ns = 0;
* masterConfig.sclGlitchFilterWidth_ns = 0;
*/
LPI2C_MasterGetDefaultConfig(&masterConfig);
/* Change the default baudrate configuration */
masterConfig.baudRate_Hz = LPI2C_BAUDRATE;
/* Initialize the LPI2C master peripheral */
LPI2C_MasterInit(EXAMPLE_I2C_MASTER, &masterConfig, LPI2C_MASTER_CLOCK_FREQUENCY);
/* Send master blocking data to slave */
if (kStatus_Success == LPI2C_MasterStart(EXAMPLE_I2C_MASTER, LPI2C_MASTER_SLAVE_ADDR_7BIT, kLPI2C_Write))
{
/* Check master tx FIFO empty or not */
LPI2C_MasterGetFifoCounts(EXAMPLE_I2C_MASTER, NULL, &txCount);
while (txCount)
{
LPI2C_MasterGetFifoCounts(EXAMPLE_I2C_MASTER, NULL, &txCount);
}
/* Check communicate with slave successful or not */
if (LPI2C_MasterGetStatusFlags(EXAMPLE_I2C_MASTER) & kLPI2C_MasterNackDetectFlag)
{
return kStatus_LPI2C_Nak;
}
/* subAddress = 0x01, data = g_master_txBuff - write to slave.
start + slaveaddress(w) + subAddress + length of data buffer + data buffer + stop*/
reVal = LPI2C_MasterSend(EXAMPLE_I2C_MASTER, &deviceAddress, 1);
if (reVal != kStatus_Success)
{
if (reVal == kStatus_LPI2C_Nak)
{
LPI2C_MasterStop(EXAMPLE_I2C_MASTER);
}
return -1;
}
reVal = LPI2C_MasterSend(EXAMPLE_I2C_MASTER, g_master_txBuff, LPI2C_DATA_LENGTH);
if (reVal != kStatus_Success)
{
if (reVal == kStatus_LPI2C_Nak)
{
LPI2C_MasterStop(EXAMPLE_I2C_MASTER);
}
return -1;
}
reVal = LPI2C_MasterStop(EXAMPLE_I2C_MASTER);
if (reVal != kStatus_Success)
{
return -1;
}
}
/* Wait until the slave is ready for transmit, wait time depend on user's case.
Slave devices that need some time to process received byte or are not ready yet to
send the next byte, can pull the clock low to signal to the master that it should wait.*/
for (uint32_t i = 0U; i < WAIT_TIME; i++)
{
__NOP();
}
PRINTF("Receive sent data from slave :");
/* Receive blocking data from slave */
/* subAddress = 0x01, data = g_master_rxBuff - read from slave.
start + slaveaddress(w) + subAddress + repeated start + slaveaddress(r) + rx data buffer + stop */
if (kStatus_Success == LPI2C_MasterStart(EXAMPLE_I2C_MASTER, LPI2C_MASTER_SLAVE_ADDR_7BIT, kLPI2C_Write))
{
/* Check master tx FIFO empty or not */
LPI2C_MasterGetFifoCounts(EXAMPLE_I2C_MASTER, NULL, &txCount);
while (txCount)
{
LPI2C_MasterGetFifoCounts(EXAMPLE_I2C_MASTER, NULL, &txCount);
}
/* Check communicate with slave successful or not */
if (LPI2C_MasterGetStatusFlags(EXAMPLE_I2C_MASTER) & kLPI2C_MasterNackDetectFlag)
{
return kStatus_LPI2C_Nak;
}
reVal = LPI2C_MasterSend(EXAMPLE_I2C_MASTER, &deviceAddress, 1);
if (reVal != kStatus_Success)
{
if (reVal == kStatus_LPI2C_Nak)
{
LPI2C_MasterStop(EXAMPLE_I2C_MASTER);
}
return -1;
}
reVal = LPI2C_MasterRepeatedStart(EXAMPLE_I2C_MASTER, LPI2C_MASTER_SLAVE_ADDR_7BIT, kLPI2C_Read);
if (reVal != kStatus_Success)
{
return -1;
}
reVal = LPI2C_MasterReceive(EXAMPLE_I2C_MASTER, g_master_rxBuff, LPI2C_DATA_LENGTH - 1);
if (reVal != kStatus_Success)
{
if (reVal == kStatus_LPI2C_Nak)
{
LPI2C_MasterStop(EXAMPLE_I2C_MASTER);
}
return -1;
}
reVal = LPI2C_MasterStop(EXAMPLE_I2C_MASTER);
if (reVal != kStatus_Success)
{
return -1;
}
}
for (uint32_t i = 0U; i < LPI2C_DATA_LENGTH - 1; i++)
{
if (i % 8 == 0)
{
PRINTF("\r\n");
}
PRINTF("0x%2x ", g_master_rxBuff[i]);
}
PRINTF("\r\n\r\n");
/* Transfer completed. Check the data.*/
for (uint32_t i = 0U; i < LPI2C_DATA_LENGTH - 1U; i++)
{
if (g_master_rxBuff[i] != g_master_txBuff[i + 1])
{
PRINTF("\r\nError occurred in the transfer ! \r\n");
break;
}
}
PRINTF("\r\nEnd of LPI2C example .\r\n");
while (1)
{
}
}
特意量了下波形发现波形异常如下：
LPI2C通信波形所示。
从图中看到只发了个start信号，就异常了，地址都没发出去。
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