bossay_release_out/app/A19_MXL90614/src/smbus.c

#include "mlx90614.h"
#include "smbus.h"
#include "hi_time.h"


/***************************************************************************
* @brief      SMBus start bit
* @param      None
* @retval     None
****************************************************************************/
void SMBus_Start(void)
{
	SMBUS_SDA_H();
    hi_udelay(5);
	SMBUS_SCL_H();
	hi_udelay(5);
	SMBUS_SDA_L();
	hi_udelay(5);
	SMBUS_SCL_L();
	hi_udelay(5);
}

/***************************************************************************
* @brief      SMBus stop bit
* @param      None
* @retval     None
****************************************************************************/
void SMBus_Stop(void)
{
    SMBUS_SCL_L();
    hi_udelay(5);
	SMBUS_SDA_L();
	hi_udelay(5);
	SMBUS_SCL_H();
	hi_udelay(5);
	SMBUS_SDA_H();
}
/*******************************************************************************
* 函数名: SMBus_SendBit
* 功能: Send a bit on SMBus 82.5kHz
* Input          : bit_out
* Output         : None
* Return         : None
*******************************************************************************/
void SMBus_SendBit(uint8_t bit_out)
{
    if(bit_out==0)
    {
        SMBUS_SDA_L();
    }
    else
    {
        SMBUS_SDA_H();
    }
    hi_udelay(2);                                        // Tsu:dat = 250ns minimum
    SMBUS_SCL_H();                                        // Set SCL line
    hi_udelay(6);                                        // High Level of Clock Pulse
    SMBUS_SCL_L();                                        // Clear SCL line
    hi_udelay(3);                                        // Low Level of Clock Pulse
    return;
}
static uint8_t SMBUS_SDA_READ(void)
{
	IotGpioValue temp = {0};
    IoTGpioGetInputVal(WIFI_IOT_IO_NAME_GPIO_12,&temp);
    return temp;
}

/*******************************************************************************
* Function Name  : SMBus_ReceiveBit
* Description    : Receive a bit on SMBus
* Input          : None
* Output         : None
* Return         : Ack_bit
*******************************************************************************/
uint8_t SMBus_ReceiveBit(void)
{
    uint8_t Ack_bit;

    SMBUS_SDA_H();          //引脚靠外部电阻上拉，当作输入
    hi_udelay(2);                        // High Level of Clock Pulse
    SMBUS_SCL_H();                        // Set SCL line
    hi_udelay(5);                        // High Level of Clock Pulse
    if (SMBUS_SDA_READ())
    {
        Ack_bit=1;
    }
    else
    {
        Ack_bit=0;
    }
    SMBUS_SCL_L();                        // Clear SCL line
    hi_udelay(3);                        // Low Level of Clock Pulse

    return        Ack_bit;
}

/*******************************************************************************
* 函数名: SMBus_SendByte
* 功能: Send a byte on SMBus
* Input          : Tx_buffer
* Output         : None
* Return         : None
*******************************************************************************/
uint8_t SMBus_SendByte(uint8_t Tx_buffer)
{
    uint8_t        Bit_counter;
    uint8_t        Ack_bit;
    uint8_t        bit_out;

    for(Bit_counter=8; Bit_counter; Bit_counter--)
    {
        if (Tx_buffer&0x80)
        {
            bit_out=1;   // If the current bit of Tx_buffer is 1 set bit_out
        }
        else
        {
            bit_out=0;  // else clear bit_out
        }
        SMBus_SendBit(bit_out);                // Send the current bit on SDA
        Tx_buffer<<=1;                                // Get next bit for checking
    }

    Ack_bit=SMBus_ReceiveBit();                // Get acknowledgment bit
    return        Ack_bit;
}

/*******************************************************************************
* 函数名: SMBus_ReceiveByte
* 功能: Receive a byte on SMBus
* Input          : ack_nack
* Output         : None
* Return         : RX_buffer
*******************************************************************************/
uint8_t SMBus_ReceiveByte(uint8_t ack_nack)
{
    uint8_t         RX_buffer;
    uint8_t        Bit_Counter;

    for(Bit_Counter=8; Bit_Counter; Bit_Counter--)
    {
        if(SMBus_ReceiveBit())                        // Get a bit from the SDA line
        {
            RX_buffer <<= 1;                        // If the bit is HIGH save 1  in RX_buffer
            RX_buffer |=0x01;
        }
        else
        {
            RX_buffer <<= 1;                        // If the bit is LOW save 0 in RX_buffer
            RX_buffer &=0xfe;
        }
    }
    SMBus_SendBit(ack_nack);                        // Sends acknowledgment bit
    return RX_buffer;
}