[Help] Hardware IIC slave problem of stm8s103f3p6

kiverin

[Help] Hardware IIC slave problem of stm8s103f3p6 [Copy link]

Dear experts, I encountered a problem when debugging the iic slave of stm8. When the host sends the device number and address, the slave responds to ack normally, but when the host starts to read data, there is no ack response. What is the reason? The code is as follows

#include "stm8s.h"
#include "stm8s_clk.h"
//#include "stm8s_type.h"
#include "I2c_slave_interrupt.h"
#define MAX_BUFFER 32

u8 u8_My_Buffer[MAX_BUFFER]={0x01,0x02,0x03,0x04};
u8 *u8_MyBuffp;
u8 MessageBegin;

// ********************** Data link function ****************************
// * These functions must be modified according to your application neeeds *
// * See AN document for more precision
// **********************************************************************

void I2C_transaction_begin(void)
{
MessageBegin = TRUE;
}
void I2C_transaction_end(void)
{
//Not used in this example
}
void I2C_byte_received(u8 u8_RxData)
{
if (MessageBegin == TRUE && u8_RxData < MAX_BUFFER) {
u8_MyBuffp= &u8_My_Buffer[u8_RxData];
MessageBegin = FALSE;
}
else if(u8_MyBuffp < &u8_My_Buffer[MAX_BUFFER])
*(u8_MyBuffp++) = u8_RxData;
}
u8 I2C_byte_write(void)
{
if (u8_MyBuffp < &u8_My_Buffer[MAX_BUFFER])
return *(u8_MyBuffp++);
else
return 0x00;
}

// ********************** Data link interrupt handler *******************

INTERRUPT_HANDLER(I2C_IRQHandler, 19)

{
static u8 sr1 = 0;
static u8 sr2 = 0;
static u8 sr3 = 0;
sr1 = I2C->SR1;
sr2 = I2C->SR2;
sr2 = I2C->SR3;

/* Communication error? */
if (sr2 & (I2C_SR2_WUFH | I2C_SR2_OVR |I2C_SR2_ARLO |I2C_SR2_BERR))
{
I2C->CR2|= I2C_CR2_STOP; // stop communication - release the lines
I2C->SR2= 0; // clear all error flags
}
/* More bytes received ? */
if ((sr1 & (I2C_SR1_RXNE | I2C_SR1_BTF)) == (I2C_SR1_RXNE | I2C_SR1_BTF))
{
I2C_byte_received(I2C->DR);
}
/* Byte received ? */
if (sr1 & I2C_SR1_RXNE)
{
I2C_byte_received(I2C->DR);
}
/* NAK? (=end of slave transmit comm) */
if (sr2 & I2C_SR2_AF)
{
I2C->SR2 &= ~I2C_SR2_AF; // clear AF
//I2C_transaction_end();
}
/* Stop bit from Master (= end of slave receive comm) */
if (sr1 & I2C_SR1_STOPF)
{
I2C->CR2 |= I2C_CR2_ACK; // CR2 write to clear STOPF
//I2C_transaction_end();
}
/* Slave address matched (= Start Comm) */
if (sr1 & I2C_SR1_ADDR)
{
I2C_transaction_begin();
}
/* More bytes to transmit ? */
if ((sr1 & (I2C_SR1_TXE | I2C_SR1_BTF)) == (I2C_SR1_TXE | I2C_SR1_BTF))
{
I2C->DR = I2C_byte_write();
}
/* Byte to transmit ? */
if (sr1 & I2C_SR1_TXE)
{
I2C->DR = I2C_byte_write();
}
GPIOD->ODR^=1;
}

// ************************* I2C init Function *************************

void Init_I2C (void)
{
/* Set I2C registers for 7Bits Address */
I2C->CR1 |= 0x01; // Enable I2C peripheral
I2C->CR2 = 0x04; // Enable I2C acknowledgement
I2C->FREQR = 8; // Set I2C Freq value (16MHz)
I2C->OARL = (SLAVE_ADDRESS<<1); // set slave address to 0x51 (put 0xA2 for the register dues to7bit address)
I2C->OARH = 0x40; // Set 7bit address mode

I2C->ITR = 0x07; // all I2C interrupt enable
}

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/
/* Public functions ----------------------------------------------------------*/

/*
* Example firmware main entry point.
* Parameters: None
* Retval . None
*/

void main(void)
{

CLK_PeripheralClockConfig(CLK_PERIPHERAL_I2C, ENABLE); //Initialize I2C clock
CLK->SWR=CLK_CKDIVR_HSIDIV; //Clock selection is HSI
CLK->CKDIVR = 0; // sys clock /1

/* Init GPIO for I2C use */
GPIOB->CR1 |= 0x30;
GPIOB->DDR &= ~0x30;
GPIOB->CR2 &= ~0x30;

/* Initialise I2C for communication */
Init_I2C();

/* Enable general interrupts */
enableInterrupts();

/*Main Loop */
while(1);
}

void assert_failed(uint8_t* File, uint32_t line)
{
while (1);
}

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Timing of the IIC bus read out by the logic analyzer

kiverin

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