I2C Interface is not working on STNRG388A

Question

I am trying to communicate with MAX30205 using STLUX385/STNRG388A. I'm using STM8S standard peripheral libraries to communicate with I2C bus. For STNRG388A device drivers, I'm using STLUX385 drivers provided by ST. I can read/write GPIOs, UART communication successfully. But when i tried the I2C bus communication, it's not working as expected. My main.c code is below, rest of the task is in the stlux_it.c in INTERRUPT_HANDLER(I2C_IRQHandler,19)

void main ( void )
{
    // work with HSI at maximum frequency
    CLK_HSIPrescalerConfig(CLK_PRESCALER_HSIDIV1);        
    // enable PLL - Used by the SMED
    CLK_PLLCmd(ENABLE);
    while((CLK->PLLR & CLK_PLLR_LOCKP) == 0);

    // initialize the GPIO registers
    GPIO_Init(GPIO1, GPIO_PIN_6, GPIO_MODE_OUT_PP_HIGH_FAST);
    GPIO_Init(GPIO1, GPIO_PIN_7, GPIO_MODE_OUT_PP_HIGH_FAST);

    I2C_DeInit();
    CLK_PeripheralClockConfig(CLK_PERIPHERAL_I2C, ENABLE);
    I2C_Cmd(ENABLE);
    I2C_Init(I2C_SPEED, SLAVE_ADDRESS, I2C_DUTYCYCLE_2, I2C_ACK_CURR, I2C_ADDMODE_7BIT,16);// (CLK_GetClockFreq()/1000000));
    I2C_ITConfig((I2C_IT_TypeDef)(I2C_IT_EVT | I2C_IT_BUF), ENABLE);
    rim();
    /* TXBuffer initialization */
    for (i = 0; i < BUFFERSIZE; i++)
        TxBuffer[i] = i;
    I2C_GenerateSTART(ENABLE);
    while (NumOfBytes);
    while (I2C_GetFlagStatus(I2C_FLAG_BUSBUSY));
    /* Add a delay to be sure that communication is finished */
    Delay(0xFFFF);

    while(1);
}

I have checked the MAX30205 with arduino and it's working fine. Waiting for any positive response. Thanks in advance. Regards

Answer 1

We need to configure STNRG388A registers for using Pin 17(SDA) & Pin 18(SCL) as I2C lines. This can be done using the below code in I2C_Init()

//define SDA, SCL outputs, HiZ, Open drain, Fast
GPIO_Init(GPIO1, GPIO_PIN_6, GPIO_MODE_OUT_PP_HIGH_FAST); // Pin 17
GPIO_Init(GPIO1, GPIO_PIN_7, GPIO_MODE_OUT_PP_HIGH_FAST); // Pin 18
MSC->IDXADD = ((u8)0x13);
MSC->IDXDAT = ((u8)MSC_IOMXP2_SEL_P54 & (u8)0x20);

Below line should be added in stlux385.h

#define MSC_IOMXP2_SEL_P54      ((u8)0x30) /*!< Port2[5:4] I/O multiplexing scheme */