SCK---PB6SDA---PB7
串口1输出温度值
单片机源程序如下:
- /* Includes ------------------------------------------------------------------*/
- #include "mlx90614.h"
- /* Private typedef -----------------------------------------------------------*/
- /* Private define ------------------------------------------------------------*/
- #define ACK 0
- #define NACK 1
- #define SA 0x00 //Slave address ??MLX90614????0x00,????????0x5a
- #define RAM_ACCESS 0x00 //RAM access command
- #define EEPROM_ACCESS 0x20 //EEPROM access command
- #define RAM_TOBJ1 0x07 //To1 address in the eeprom
- #define SMBUS_PORT GPIOB
- #define SMBUS_SCK GPIO_Pin_6
- #define SMBUS_SDA GPIO_Pin_7
- #define RCC_APB2Periph_SMBUS_PORT RCC_APB2Periph_GPIOB
- #define SMBUS_SCK_H() SMBUS_PORT->BSRR = SMBUS_SCK
- #define SMBUS_SCK_L() SMBUS_PORT->BRR = SMBUS_SCK
- #define SMBUS_SDA_H() SMBUS_PORT->BSRR = SMBUS_SDA
- #define SMBUS_SDA_L() SMBUS_PORT->BRR = SMBUS_SDA
- #define SMBUS_SDA_PIN() SMBUS_PORT->IDR & SMBUS_SDA //??????
- /* Private macro -------------------------------------------------------------*/
- /* Private variables ---------------------------------------------------------*/
- /*******************************************************************************
- * Function Name : SMBus_Init
- * Description : SMBus???
- * Input : None
- * Output : None
- * Return : None
- *******************************************************************************/
- void SMBus_Init()
- {
- GPIO_InitTypeDef GPIO_InitStructure;
- /* Enable SMBUS_PORT clocks */
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_SMBUS_PORT, ENABLE);
- /*??SMBUS_SCK?SMBUS_SDA????????*/
- GPIO_InitStructure.GPIO_Pin = SMBUS_SCK | SMBUS_SDA;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_Init(SMBUS_PORT, &GPIO_InitStructure);
- SMBUS_SCK_H();
- SMBUS_SDA_H();
- }
- /*******************************************************************************
- * Function Name : SMBus_StartBit
- * Description : Generate START condition on SMBus
- * Input : None
- * Output : None
- * Return : None
- *******************************************************************************/
- void SMBus_StartBit(void)
- {
- SMBUS_SDA_H(); // Set SDA line
- SMBus_Delay(1); // Wait a few microseconds
- SMBUS_SCK_H(); // Set SCL line
- SMBus_Delay(5); // Generate bus free time between Stop
- SMBUS_SDA_L(); // Clear SDA line
- SMBus_Delay(10); // Hold time after (Repeated) Start
- // Condition. After this period, the first clock is generated.
- //(Thd:sta=4.0us min)
- SMBUS_SCK_L(); // Clear SCL line
- SMBus_Delay(2); // Wait a few microseconds
- }
- /*******************************************************************************
- * Function Name : SMBus_StopBit
- * Description : Generate STOP condition on SMBus
- * Input : None
- * Output : None
- * Return : None
- *******************************************************************************/
- void SMBus_StopBit(void)
- {
- SMBUS_SCK_L(); // Clear SCL line
- SMBus_Delay(5); // Wait a few microseconds
- SMBUS_SDA_L(); // Clear SDA line
- SMBus_Delay(5); // Wait a few microseconds
- SMBUS_SCK_H(); // Set SCL line
- SMBus_Delay(10); // Stop condition setup time(Tsu:sto=4.0us min)
- SMBUS_SDA_H(); // Set SDA line
- }
- /*******************************************************************************
- * Function Name : SMBus_SendByte
- * Description : Send a byte on SMBus
- * Input : Tx_buffer
- * Output : None
- * Return : None
- *******************************************************************************/
- u8 SMBus_SendByte(u8 Tx_buffer)
- {
- u8 Bit_counter;
- u8 Ack_bit;
- u8 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;
- }
- /*******************************************************************************
- * Function Name : SMBus_SendBit
- * Description : Send a bit on SMBus
- * Input : bit_out
- * Output : None
- * Return : None
- *******************************************************************************/
- void SMBus_SendBit(u8 bit_out)
- {
- if(bit_out==0)
- {
- SMBUS_SDA_L();
- }
- else
- {
- SMBUS_SDA_H();
- }
- SMBus_Delay(2); // Tsu:dat = 250ns minimum
- SMBUS_SCK_H(); // Set SCL line
- SMBus_Delay(10); // High Level of Clock Pulse
- SMBUS_SCK_L(); // Clear SCL line
- SMBus_Delay(10); // Low Level of Clock Pulse
- // SMBUS_SDA_H(); // Master release SDA line ,
- return;
- }
- /*******************************************************************************
- * Function Name : SMBus_ReceiveBit
- * Description : Receive a bit on SMBus
- * Input : None
- * Output : None
- * Return : Ack_bit
- *******************************************************************************/
- u8 SMBus_ReceiveBit(void)
- {
- u8 Ack_bit;
- SMBUS_SDA_H(); //?????????,????
- SMBUS_SCK_H(); // Set SCL line
- SMBus_Delay(2); // High Level of Clock Pulse
- if (SMBUS_SDA_PIN())
- {
- Ack_bit=1;
- }
- else
- {
- Ack_bit=0;
- }
- SMBUS_SCK_L(); // Clear SCL line
- SMBus_Delay(4); // Low Level of Clock Pulse
- return Ack_bit;
- }
- /*******************************************************************************
- * Function Name : SMBus_ReceiveByte
- * Description : Receive a byte on SMBus
- * Input : ack_nack
- * Output : None
- * Return : RX_buffer
- *******************************************************************************/
- u8 SMBus_ReceiveByte(u8 ack_nack)
- {
- u8 RX_buffer;
- u8 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;
- }
- /*******************************************************************************
- * Function Name : SMBus_Delay
- * Description : ?? ?????1us
- * Input : time
- * Output : None
- * Return : None
- *******************************************************************************/
- void SMBus_Delay(u16 time)
- {
- u16 i, j;
- for (i=0; i<4; i++)
- {
- for (j=0; j<time; j++);
- }
- }
- /*******************************************************************************
- * Function Name : SMBus_ReadMemory
- * Description : READ DATA FROM RAM/EEPROM
- * Input : slaveAddress, command
- * Output : None
- * Return : Data
- *******************************************************************************/
- u16 SMBus_ReadMemory(u8 slaveAddress, u8 command)
- {
- u16 data; // Data storage (DataH:DataL)
- u8 Pec; // PEC byte storage
- u8 DataL=0; // Low data byte storage
- u8 DataH=0; // High data byte storage
- u8 arr[6]; // Buffer for the sent bytes
- u8 PecReg; // Calculated PEC byte storage
- u8 ErrorCounter; // Defines the number of the attempts for communication with MLX90614
- ErrorCounter=0x00; // Initialising of ErrorCounter
- slaveAddress <<= 1; //2-7???????
-
- do
- {
- repeat:
- SMBus_StopBit(); //If slave send NACK stop comunication
- --ErrorCounter; //Pre-decrement ErrorCounter
- if(!ErrorCounter) //ErrorCounter=0?
- {
- break; //Yes,go out from do-while{}
- }
- SMBus_StartBit(); //Start condition
- if(SMBus_SendByte(slaveAddress))//Send SlaveAddress ???Wr=0????????
- {
- goto repeat; //Repeat comunication again
- }
- if(SMBus_SendByte(command)) //Send command
- {
- goto repeat; //Repeat comunication again
- }
- SMBus_StartBit(); //Repeated Start condition
- if(SMBus_SendByte(slaveAddress+1)) //Send SlaveAddress ???Rd=1????????
- {
- goto repeat; //Repeat comunication again
- }
- DataL = SMBus_ReceiveByte(ACK); //Read low data,master must send ACK
- DataH = SMBus_ReceiveByte(ACK); //Read high data,master must send ACK
- Pec = SMBus_ReceiveByte(NACK); //Read PEC byte, master must send NACK
- SMBus_StopBit(); //Stop condition
- arr[5] = slaveAddress; //
- arr[4] = command; //
- arr[3] = slaveAddress+1; //Load array arr
- arr[2] = DataL; //
- arr[1] = DataH; //
- arr[0] = 0; //
- PecReg=PEC_Calculation(arr);//Calculate CRC
- }
- while(PecReg != Pec); //If received and calculated CRC are equal go out from do-while{}
- data = (DataH<<8) | DataL; //data=DataH:DataL
- return data;
- }
- /*******************************************************************************
- * Function Name : PEC_calculation
- * Description : Calculates the PEC of received bytes
- * Input : pec[]
- * Output : None
- * Return : pec[0]-this byte contains calculated crc value
- *******************************************************************************/
- u8 PEC_Calculation(u8 pec[])
- {
- u8 crc[6];
- u8 BitPosition=47;
- u8 shift;
- u8 i;
- u8 j;
- u8 temp;
- do
- {
- /*Load pattern value 0x000000000107*/
- crc[5]=0;
- crc[4]=0;
- crc[3]=0;
- crc[2]=0;
- crc[1]=0x01;
- crc[0]=0x07;
- /*Set maximum bit position at 47 ( six bytes byte5...byte0,MSbit=47)*/
- BitPosition=47;
- /*Set shift position at 0*/
- shift=0;
- /*Find first "1" in the transmited message beginning from the MSByte byte5*/
- i=5;
- j=0;
- while((pec[i]&(0x80>>j))==0 && i>0)
- {
- BitPosition--;
- if(j<7)
- {
- j++;
- }
- else
- {
- j=0x00;
- i--;
- }
- }/*End of while */
- /*Get shift value for pattern value*/
- shift=BitPosition-8;
- /*Shift pattern value */
- ……………………
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