[参考译文] MSP430G2253：I2C 信号数据包丢失问题

https://e2e.ti.com/support/microcontrollers/msp-low-power-microcontrollers-group/msp430/f/msp-low-power-microcontroller-forum/1307998/msp430g2253-i2c-signal-packet-loss-problem

您好、工程师：
我使用 MSP430G2553IPW20。 将其 P1.6和 P1.7连接到 DLPC 3478、IO 配置为模拟 I2C、发送的指令为36 9E 00 00。 测试表明将会发生数据包丢失、这将每几十到几百次发生一次。

下图显示了正常通信期间的时间序列：

下图显示了丢失照片的顺序：

过去使用 P1.4和 P1.5IO 对 I2C 进行仿真。 经过许多测试、都没有数据包丢失问题。 由于电路设计最近已更改、IO 已更改、代码刚刚交换了 IO 配置、因此发现了此问题。

您能帮助我分析一下出现了什么问题吗？

与 I2C 相关的硬件如下所示：

I2C 相关代码如下所示：

/*****************************************************************************
**
**             TEXAS INSTRUMENTS PROPRIETARY INFORMATION
**
**  (c) Copyright, Texas Instruments Incorporated, 2009
**      All Rights Reserved.
**
**  Property of Texas Instruments Incorporated. Restricted Rights -
**  Use, duplication, or disclosure is subject to restrictions set
**  forth in TI's program license agreement and associated documentation.
******************************************************************************/
/*************************************************************
* THIS PROGRAM IS PROVIDED "AS IS." TI MAKES NO WARRANTIES OR
* REPRESENTATIONS, EITHER EXPRESS, IMPLIED OR STATUTORY,
* INCLUDING ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE, LACK OF VIRUSES, ACCURACY OR
* COMPLETENESS OF RESPONSES, RESULTS AND LACK OF NEGLIGENCE.
* TI DISCLAIMS ANY WARRANTY OF TITLE, QUIET ENJOYMENT, QUIET
* POSSESSION, AND NON-INFRINGEMENT OF ANY THIRD PARTY
* INTELLECTUAL PROPERTY RIGHTS WITH REGARD TO THE PROGRAM OR
* YOUR USE OF THE PROGRAM.
*
* IN NO EVENT SHALL TI BE LIABLE FOR ANY SPECIAL, INCIDENTAL,
* CONSEQUENTIAL OR INDIRECT DAMAGES, HOWEVER CAUSED, ON ANY
* THEORY OF LIABILITY AND WHETHER OR NOT TI HAS BEEN ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGES, ARISING IN ANY WAY OUT
* OF THIS AGREEMENT, THE PROGRAM, OR YOUR USE OF THE PROGRAM.
* EXCLUDED DAMAGES INCLUDE, BUT ARE NOT LIMITED TO, COST OF
* REMOVAL OR REINSTALLATION, COMPUTER TIME, LABOR COSTS, LOSS
* OF GOODWILL, LOSS OF PROFITS, LOSS OF SAVINGS, OR LOSS OF
* USE OR INTERRUPTION OF BUSINESS.  IN NO EVENT WILL TI'S
* AGGREGATE LIABILITY UNDER THIS AGREEMENT OR ARISING OUT OF
* YOUR USE OF THE PROGRAM EXCEED FIVE HUNDRED DOLLARS
* (U.S.$500).
*
* Unless otherwise stated, the Program is written and copyrighted
* by Texas Instruments is distributed as "freeware."  You may,
* only under TI's copyright in the Program, use and modify the
* Program without any charge or restriction.  You may
* distribute to third parties, provided that you transfer a
* copy of this license to the third party and the third party
* agrees to these terms by its first use of the Program.  In
* jurisdictions in which use is not deemed acceptance of these
* terms, no license is granted and no use is permitted.  You
* must reproduce the copyright notice and any other legend of
* ownership on each copy or partial copy of the Program.
*
* You acknowledge and agree that the Program contains
* copyrighted material, trade secrets and other TI proprietary
* information and is protected by copyright laws,
* international copyright treaties, and trade secret laws, as
* well as other intellectual property laws.  You agree that in
* no event will you alter, remove or destroy any copyright
* notice included in the Program.  TI reserves all rights not
* specifically granted under this license.  Except as
* specifically provided herein, nothing in this agreement
* shall be construed as conferring upon you, by implication,
* estoppel, or otherwise, any license or other right under any
* TI patents, copyrights or trade secrets.
*************************************************************/
#ifndef __i2c_master
#define __i2c_master

#ifdef __cplusplus
extern "C" {
#endif

// defines
#define I2C_NO_ACK                 0
//***********functions 软件i2C**********************************/
uint08  I2C_PolledMasterWrite(uint08 device_addr, uint08* write_data, uint08 num_bytes);
uint08  I2C_PolledMasterRead(uint08 device_addr, uint08* read_data, uint08 num_bytes);

void   I2C_Master_Init (void);


void    I2C_Master_Start(void);
uint08   I2C_Master_Stop(void);
uint08  I2C_MasterTransmitByte(uint08 data);
uint08  I2C_MasterReceiveByte(void);



//***********functions 软件i2C**********************************/


/*
void i2c_hw_init(void);//不支持P14&P15
void set_devaddr(uint08 dev_addr);
int i2c_hw_write(uint08 dev_addr, int32 inlen, unsigned char *pdata);
int i2c_hw_read(uint08 dev_addr, int32 inlen, unsigned char *pdata);
int i2c_dpp_write(uint08 dev_addr, unsigned char cmd , int outlen, unsigned char *pdata);
int i2c_dpp_read(uint08 dev_addr, unsigned char cmd , int inlen, unsigned char *pdata);
int i2c_sil9293_write(uint08 dev_addr, unsigned char cmd , int outlen, unsigned char *pdata);
int i2c_sil9293_read(uint08 dev_addr, unsigned char cmd , int inlen, unsigned char *pdata);
*/

#ifdef __cplusplus      /* matches __cplusplus construct above */
}
#endif

#endif // #ifndef __i2c_master

/*****************************************************************************
**
**             TEXAS INSTRUMENTS PROPRIETARY INFORMATION
**
**  (c) Copyright, Texas Instruments Incorporated, 2009
**      All Rights Reserved.
**
**  Property of Texas Instruments Incorporated. Restricted Rights -
**  Use, duplication, or disclosure is subject to restrictions set
**  forth in TI's program license agreement and associated documentation.
******************************************************************************/
/*************************************************************
* THIS PROGRAM IS PROVIDED "AS IS." TI MAKES NO WARRANTIES OR
* REPRESENTATIONS, EITHER EXPRESS, IMPLIED OR STATUTORY,
* INCLUDING ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE, LACK OF VIRUSES, ACCURACY OR
* COMPLETENESS OF RESPONSES, RESULTS AND LACK OF NEGLIGENCE.
* TI DISCLAIMS ANY WARRANTY OF TITLE, QUIET ENJOYMENT, QUIET
* POSSESSION, AND NON-INFRINGEMENT OF ANY THIRD PARTY
* INTELLECTUAL PROPERTY RIGHTS WITH REGARD TO THE PROGRAM OR
* YOUR USE OF THE PROGRAM.
*
* IN NO EVENT SHALL TI BE LIABLE FOR ANY SPECIAL, INCIDENTAL,
* CONSEQUENTIAL OR INDIRECT DAMAGES, HOWEVER CAUSED, ON ANY
* THEORY OF LIABILITY AND WHETHER OR NOT TI HAS BEEN ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGES, ARISING IN ANY WAY OUT
* OF THIS AGREEMENT, THE PROGRAM, OR YOUR USE OF THE PROGRAM.
* EXCLUDED DAMAGES INCLUDE, BUT ARE NOT LIMITED TO, COST OF
* REMOVAL OR REINSTALLATION, COMPUTER TIME, LABOR COSTS, LOSS
* OF GOODWILL, LOSS OF PROFITS, LOSS OF SAVINGS, OR LOSS OF
* USE OR INTERRUPTION OF BUSINESS.  IN NO EVENT WILL TI'S
* AGGREGATE LIABILITY UNDER THIS AGREEMENT OR ARISING OUT OF
* YOUR USE OF THE PROGRAM EXCEED FIVE HUNDRED DOLLARS
* (U.S.$500).
*
* Unless otherwise stated, the Program is written and copyrighted
* by Texas Instruments is distributed as "freeware."  You may,
* only under TI's copyright in the Program, use and modify the
* Program without any charge or restriction.  You may
* distribute to third parties, provided that you transfer a
* copy of this license to the third party and the third party
* agrees to these terms by its first use of the Program.  In
* jurisdictions in which use is not deemed acceptance of these
* terms, no license is granted and no use is permitted.  You
* must reproduce the copyright notice and any other legend of
* ownership on each copy or partial copy of the Program.
*
* You acknowledge and agree that the Program contains
* copyrighted material, trade secrets and other TI proprietary
* information and is protected by copyright laws,
* international copyright treaties, and trade secret laws, as
* well as other intellectual property laws.  You agree that in
* no event will you alter, remove or destroy any copyright
* notice included in the Program.  TI reserves all rights not
* specifically granted under this license.  Except as
* specifically provided herein, nothing in this agreement
* shall be construed as conferring upon you, by implication,
* estoppel, or otherwise, any license or other right under any
* TI patents, copyrights or trade secrets.
*************************************************************/

#include "common.h"
#include "i2c_master.h"
//#include "msp430f2132.h"
#include "msp430G2553.h"
#include "HWGPIO.h"
#include "delay.h"

#define SDA_HI  I2C_SetSDA_High()
#define SDA_LO  I2C_SetSDA_Low()
#define SDA_IN  I2C_GetSDA_Input()
#define SCL_HI  I2C_SetSCL_High()
#define SCL_LO  I2C_SetSCL_Low()
#define SCL_IN  I2C_GetSCL_Input()

void   I2C_SetSDA_High (void);
void   I2C_SetSDA_Low (void);
BOOL   I2C_GetSDA_Input (void);
void   I2C_SetSCL_High (void);
void   I2C_SetSCL_Low (void);
BOOL   I2C_GetSCL_Input (void);



// local functions
//uint08 i2c_master_check_nak_timeout(uint08 timeout, uint08 check_nak);
//void i2c_master_cleanup(void);


void i2c_delay_us(int n)
{
 int i; 
   for(i = 0; i < n; i++)
   {

      // __no_operation();
      // __no_operation();//ALL=15
             __no_operation();
       __no_operation();
       __no_operation();
       __no_operation();
       __no_operation();
       __no_operation();
       __no_operation();
       __no_operation();
       __no_operation();
       __no_operation();
       __no_operation();
       __no_operation();
       __no_operation();
       __no_operation();
      // __no_operation();
      // __no_operation();//ALL=15
   }
}



////////////////////////////////////////////////////////////////////////
void I2C_Master_Start(void)            // Set up start condition for I2C
/**
 * Generates the start condition for I2C read/write
 *
 */
{
	volatile uint08 i;
    SDA_HI;
    __no_operation();
    SCL_HI;

    for (i=0; i<5; i++)
    {
        __no_operation();

        SDA_LO;
        __no_operation();
        __no_operation();
        SCL_LO;

        //after end of start condition both SDA and SCL will be low
    }
}

////////////////////////////////////////////////////////////////////////
uint08 I2C_Master_Stop(void)            // Set up stop condition for I2C
/**
 * Generates the stop condition for I2C read/write
 *
 */
{
 /* 
  volatile uint08 i; unsigned short delay=2000;
  SCL_HI;
  SCL_LO;
i2c_delay_us(5);
  SDA_HI;
  SDA_LO;
i2c_delay_us(10);
	SCL_IN;
	while(delay--)
	{
		i2c_delay_us(50);
		if(~SCL_IN)
		{
			SCL_HI;
			//SCL_OUT;
			i2c_delay_us(10);
			SDA_HI;
			i2c_delay_us(40);
			SCL_IN;
			return ENABLE;
		}
	}
	SDA_IN;
 */       
        
{
  volatile uint08 i;
  
  SDA_LO;
  i2c_delay_us(5);
  
  SCL_HI;
  i2c_delay_us(5);
  SDA_HI;
  i2c_delay_us(5);
  
  i=0;
   //ensure bus is in default condition ( freed by slave)
  while(!SDA_IN) // i is just a variable to control the while loop run time.
  {
    SCL_HI;
    i2c_delay_us(5);
    SCL_LO;
    i2c_delay_us(5);
    i++;
    if( i > 25)
    {
        break;
    }
  }
  SCL_HI;
  //After generating stop condition SCL and SDA are both high. Default condition for I2C bus.
 }

  
  
	return DISABLE;
 }
////////////////////////////////////////////////////////////////////////
uint08 I2C_PolledMasterWrite(uint08 device_addr, uint08* write_data, uint08 num_bytes)//return 1 IIC_FAULT
/**
 * Writes data to the specified device address
 *
 * @param   device_addr   - I - 7 Bit device Address
 * @param   write_data    - I - Pointer to data buffer to be written to slave
 * @param   num_bytes     - I - Number of bytes to be written
 * @return  PASS - Completed successfully
 *          I2C_NO_ACK - Slave NAck'ed
 *
 */
{
      uint08 ByteCount;
      uint08 *data_ptr;
      uint08 status=PASS;
      // initialize pointer to the data and start the transfer
      data_ptr = write_data;


      // Generate START condition //
      // Data line loow when clock is high //

      I2C_Master_Start();

      // Before writing address ensure the bit 0 is set to zero
      // Bit 0 =0 means master is writing , Bit 0 =1 means master wants to read
      // BIT0 = 0x1
      if (I2C_MasterTransmitByte(device_addr & ~0x1) == I2C_NO_ACK)
      {
         // If not Acknowledged by slave//
         status =  I2C_NO_ACK;
      }
      else
      // Tranmit all the data bytes as slave has acknowledged//
      {
        for (ByteCount=0; ByteCount<num_bytes; ByteCount++)
        {
            if (I2C_MasterTransmitByte(*data_ptr)== I2C_NO_ACK)
            {
                // If not Acknowledged by slave//
                status =  I2C_NO_ACK;
                break;
            }
            else
                data_ptr++;
               //delay_ms(20);//YZP I2Cdelay
        }
      }

      // Generate STOP Condition
      // Data line high, when clock is high
      I2C_Master_Stop();

 
    return status;
}

////////////////////////////////////////////////////////////////////////
uint08 I2C_PolledMasterRead(uint08 device_addr, uint08* read_data, uint08 num_bytes)
/**
 * Reads data from the specified device address
 *
 * @param   device_addr   - I - 7 Bit device Address
 * @param   read_data     - I - Pointer to buffer to hold received data from slave
 * @param   num_bytes     - I - Number of bytes to be read
 * @return  PASS - Completed successfully
 *          I2C_NO_ACK - Slave NAck'ed
 *
 */
{
    uint08* data_ptr;
    uint08 status=PASS;
    uint08 ByteCount;
    data_ptr = read_data;


    // Generate START condition //
    // Data line low when clock is high //

      I2C_Master_Start();

    // Transmit the slave address //
    // Before writing address ensure the bit 0 is set to 1
    // Bit 0 =0 means master is writing , Bit 0 =1 means master is reading
    // BIT0 = 0x1

    if(I2C_MasterTransmitByte(device_addr | 0x1) == I2C_NO_ACK)
    {
        // If not Acknowledged //
        status =  I2C_NO_ACK;
    }
    else
    {
        // Receive all the data bytes //
        for(ByteCount = 0; ByteCount < num_bytes; ByteCount++)
        {
            *data_ptr = I2C_MasterReceiveByte();
            data_ptr++;
        }
    }

    // Generate STOP Condition
    // Data line high, when clock is high
    I2C_Master_Stop();
    return status;
}

////////////////////////////////////////////////////////////////////////
uint08 I2C_MasterTransmitByte(uint08 data)
/**
 * This routine transmits one byte of data over the given clock and data lines and
 * receives the ack from slave.
 *
 * @param   data          - I - The 8 bit data to be transmitted
 * @return  I2C_NO_ACK - Not Acknowledgeed
 *          PASS - Acknowledged
 *
 */
{
    uint08 Ack=1;
    uint08 i;
    uint08 Byte = data;
 // printf("_I2C_MasterTransmitByte_=0x%x\n", Byte);
    // Send Byte  It is assumed that the start condition would have made SCL and SDA low.
    // SDA should change only when SCA is low.

    SCL_LO;
    for(i = 0; i < 8 ; i++)
    {
        if( Byte & 0x80)
            SDA_HI;
        else
            SDA_LO;
        __no_operation();
        __no_operation();
        i2c_delay_us(2);
        
        SCL_HI;
        Byte <<= 1;

        __no_operation();  //need to optimize the delay.
        __no_operation();
        __no_operation();
        __no_operation();
        i2c_delay_us(5);
        
        SCL_LO;

        //leave SDA at the end
        if(i == 7)
        {
            SDA_HI;   
        }
        __no_operation();
        __no_operation();
        i2c_delay_us(2);
    }

    //Receive Ack
    __no_operation();
    __no_operation();
    i2c_delay_us(2);
    SCL_HI;
     
    //__no_operation();   // delay added bcoz without this delay ack was received wrong.
    //__no_operation();   // need to optimize the delay.
    i2c_delay_us(2);
    // If data line is pulled low by slave- it is acknowledged
    if (SDA_IN)
        Ack = 0;  //ack not received
    else
        Ack = 1;  //ack received
    i2c_delay_us(3);
    
    SCL_LO;
    __no_operation();
    __no_operation();
    i2c_delay_us(4);
    
    SDA_LO;

   if (Ack == 0)	printf("__W_I2C_FAULT___\n");
    //After transmitting one byte of data SCL and SDA are both low.
    return Ack;
}

////////////////////////////////////////////////////////////////////////
uint08 I2C_MasterReceiveByte()
/**
 * This routine receives one byte of data over the given clock and data lines and
 * sends the ack to slave.
 *
 * @return  one byte of data received from slave.
 *
 */
{
    uint08 Data=0;
    uint08 i;

    //Make SDA as input
    SDA_HI;
    __no_operation();
    __no_operation();
    i2c_delay_us(2);

    for(i = 0; i < 8 ; i ++)
    {
        SCL_HI;
        __no_operation();
        __no_operation();
        i2c_delay_us(2);
        Data <<= 1;
        if (SDA_IN)
            Data |=1;
        else
            Data |=0;
        
        i2c_delay_us(2);
        
        SCL_LO;
        __no_operation();
        __no_operation();
        i2c_delay_us(5);
    }

    //After the eight bits are transferred by slave, slave will pull SDA high ( default condition for I2C bus)
    // Generate ack for slave.
    SDA_LO;
    __no_operation();
    __no_operation();
    i2c_delay_us(1);
    
    SCL_HI;
    __no_operation();
    __no_operation();
    i2c_delay_us(5);
    
    SCL_LO;
    i2c_delay_us(2);
    //After receiving one byte of data SCL and SDA are both low.

    return Data;
}

//////////////////////////////////////////////////

void I2C_Master_Init(void) //P1.4=DATA,=58KHZ 17us;
/**
 * Initializes I2C. Makes SCL and SDA high.
 */
{
    //bit banging
    P1SEL &= ~(SCL | SDA);                    //&= ~��0�� Set GPIO function 
    P1OUT &= ~(SDA | SCL);

    I2C_SetSCL_Low();  //although not required but want to make sure SCL is low when SDA goes high
    I2C_SetSDA_High();
    __no_operation();
    i2c_delay_us(5);
    I2C_SetSCL_High();
    __no_operation();
    i2c_delay_us(5);
}

//////////////////////////////////////////////////
/* I2C SDA and SCL Lines */
void I2C_SetSDA_High (void)
{
    P1DIR &= ~SDA;
}

//////////////////////////////////////////////////
void I2C_SetSDA_Low (void)
{
    P1DIR |=  SDA;
}

//////////////////////////////////////////////////
BOOL I2C_GetSDA_Input (void)
{
    return (P1IN & SDA ? 1 : 0);
}

//////////////////////////////////////////////////
void I2C_SetSCL_High (void)
{
    P1DIR &= ~SCL;
}

//////////////////////////////////////////////////
void I2C_SetSCL_Low (void)
{
    P1DIR |=  SCL;
}

//////////////////////////////////////////////////
BOOL I2C_GetSCL_Input (void)
{
    return (P1IN & SCL ? 1 : 0);
}

#if 0
void i2c_hw_init(void)//P1.4 and P1.5 不支持硬件
{
  P1SEL |= BIT6 + BIT7;                     // Assign I2C pins to USCI_B0
  P1SEL2|= BIT6 + BIT7;                     // Assign I2C pins to USCI_B0
  UCB0CTL1 |= UCSWRST;                      // Enable SW reset
  UCB0CTL0 = UCMST+UCMODE_3+UCSYNC;         // I2C Master, synchronous mode
  UCB0CTL1 = UCSSEL_2+UCSWRST;              // Use SMCLK, keep SW reset
  UCB0BR0 = 12;                             // fSCL = SMCLK/12 = ~100kHz
  UCB0BR1 = 0;
  //UCB0I2CSA = 0x20;                         // Set slave address
  UCB0CTL1 &= ~UCSWRST;                     // Clear SW reset, resume operation
  //IE2 |= UCB0TXIE; 
}

void set_devaddr(uint08 dev_addr)
{
   UCB0I2CSA = dev_addr >> 1;
}

unsigned char iic1_buffer[16];

int i2c_hw_write(uint08 dev_addr, int32 inlen, unsigned char *pdata)
{
    volatile int32 i;

    set_devaddr(dev_addr);
    while (UCB0CTL1 & UCTXSTP);             // Ensure stop condition got sent
    //i = UCB0STAT;
    UCB0CTL1 |= UCTR + UCTXSTT;
    //while (UCB0CTL1 & UCTXSTT);
    for(i = 0; i < inlen; i++)
    {
        //while(((IFG2 & UCB0TXIFG) == 0) && ((UCB0STAT & 0x08) == 0));
        while(((IFG2 & UCB0TXIFG) == 0));
        if(UCB0STAT & 0x08)
        { 
           UCB0CTL1 |= UCTXSTP; 
           while (UCB0CTL1 & UCTXSTP); 
           
           return -1;
        }
        UCB0TXBUF = pdata[i];
    }
    UCB0CTL1 |= UCTXSTP; 
    while (UCB0CTL1 & UCTXSTP); 
    
    return 1;
}


int i2c_hw_read(uint08 dev_addr, int32 inlen, unsigned char *pdata)
{
    int32 i;
 
    set_devaddr(dev_addr);
    while (UCB0CTL1 & UCTXSTP);             // Ensure stop condition got sent
    
    UCB0CTL1 &= ~UCTR; 
    UCB0CTL1 |= UCTXSTT;
    //while (UCB0CTL1 & UCTXSTT);
    for(i = 0; i < inlen; i++)
    {
        //while(((IFG2 & UCB0RXIFG) == 0) && ((UCB0STAT & UCNACKIFG) == 0));
        while((IFG2 & UCB0RXIFG) == 0);
        if(UCB0STAT & UCNACKIFG)
        { 
           UCB0CTL1 |= UCTXSTP; 
            while (UCB0CTL1 & UCTXSTP); 
            
            return -1;
        }
        pdata[i] = UCB0RXBUF;
        if(i == inlen - 1)
        {
           UCB0CTL1 |= UCTXSTP; 
        }
    }
    
   while (UCB0CTL1 & UCTXSTP); 
    
    return 1;
}


int i2c_dpp_write(uint08 dev_addr, unsigned char cmd , int outlen, unsigned char *pdata)
{
    int i;
    
    for(i = 0; i < outlen; i++)
    {
       iic1_buffer[1+i] = pdata[i];
    }
    iic1_buffer[0] = cmd;
       
    return i2c_hw_write(dev_addr, i, pdata);
}

int i2c_dpp_read(uint08 dev_addr, unsigned char cmd , int inlen, unsigned char *pdata)
{
   
   unsigned char cc[2];
   
   //cc[0] = 0x15;
   cc[0] = cmd;
   if(i2c_hw_write(dev_addr, 1, cc) < 1)
      return -1;
   
   return i2c_hw_read(dev_addr, inlen, pdata);
   
}

int i2c_sil9293_write(uint08 dev_addr, unsigned char cmd , int outlen, unsigned char *pdata)
{
    int i;
    
    for(i = 0; i < outlen; i++)
    {
       iic1_buffer[1+i] = pdata[i];
    }
    iic1_buffer[0] = cmd;
       
    return i2c_hw_write(dev_addr, i, pdata);
}

int i2c_sil9293_read(uint08 dev_addr, unsigned char cmd , int inlen, unsigned char *pdata)
{
   
   unsigned char cc[2];
   
   cc[0] = cmd;
   if(i2c_hw_write(dev_addr, 1, cc) < 1)
      return -1;
   
   return i2c_hw_read(dev_addr, inlen, pdata);
   
}
#endif

我们已经调试了很长一段时间、在检查代码时没有发现任何问题。 请帮助工程师进行分析。

非常感谢！