317 lines
7.7 KiB
C
317 lines
7.7 KiB
C
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#include "mlx90614.h"
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#define ACK 0
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#define NACK 1
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#define SA 0x00
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#define RAM_ACCESS 0x00
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#define EEPROM_ACCESS 0x20
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#define RAM_TOBJ1 0x07
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#define SMBUS_PORT GPIOB
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#define SMBUS_SCK GPIO_Pin_10
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#define SMBUS_SDA GPIO_Pin_11
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#define RCC_APB2Periph_SMBUS_PORT RCC_APB2Periph_GPIOB
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#define SMBUS_SCK_H() SMBUS_PORT->BSRR = SMBUS_SCK
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#define SMBUS_SCK_L() SMBUS_PORT->BRR = SMBUS_SCK
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#define SMBUS_SDA_H() SMBUS_PORT->BSRR = SMBUS_SDA
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#define SMBUS_SDA_L() SMBUS_PORT->BRR = SMBUS_SDA
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#define SMBUS_SDA_PIN() SMBUS_PORT->IDR & SMBUS_SDA //??????
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void SMBus_StartBit(void)
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{
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SMBUS_SDA_H(); // Set SDA line
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SMBus_Delay(5); // Wait a few microseconds
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SMBUS_SCK_H(); // Set SCL line
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SMBus_Delay(5); // Generate bus free time between Stop
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SMBUS_SDA_L(); // Clear SDA line
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SMBus_Delay(5); // Hold time after (Repeated) Start
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SMBUS_SCK_L(); // Clear SCL line
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SMBus_Delay(5); // Wait a few microseconds
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}
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/*******************************************************************************
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* Function Name : SMBus_StopBit
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* Description : Generate STOP condition on SMBus
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* Input : None
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* Output : None
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* Return : None
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*******************************************************************************/
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void SMBus_StopBit(void)
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{
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SMBUS_SCK_L(); // Clear SCL line
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SMBus_Delay(5); // Wait a few microseconds
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SMBUS_SDA_L(); // Clear SDA line
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SMBus_Delay(5); // Wait a few microseconds
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SMBUS_SCK_H(); // Set SCL line
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SMBus_Delay(5); // Stop condition setup time(Tsu:sto=4.0us min)
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SMBUS_SDA_H(); // Set SDA line?SCK=1?,???SDA?0?1??????(???)
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}
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u8 SMBus_SendByte(u8 Tx_buffer)
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{
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u8 Bit_counter;
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u8 Ack_bit;
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u8 bit_out;
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for(Bit_counter=8; Bit_counter; Bit_counter--)
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{
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if (Tx_buffer&0x80)
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{
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bit_out=1; // If the current bit of Tx_buffer is 1 set bit_out
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}
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else
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{
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bit_out=0; // else clear bit_out
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}
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SMBus_SendBit(bit_out); // Send the current bit on SDA
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Tx_buffer<<=1; // Get next bit for checking
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}
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Ack_bit=SMBus_ReceiveBit(); // Get acknowledgment bit
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return Ack_bit;
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}
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void SMBus_SendBit(u8 bit_out)
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{
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if(bit_out==0)
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{
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SMBUS_SDA_L();
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}
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else
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{
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SMBUS_SDA_H();
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}
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SMBus_Delay(2); // Tsu:dat = 250ns minimum
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SMBUS_SCK_H(); // Set SCL line
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SMBus_Delay(6); // High Level of Clock Pulse
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SMBUS_SCK_L(); // Clear SCL line
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SMBus_Delay(3); // Low Level of Clock Pulse
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// SMBUS_SDA_H(); // Master release SDA line ,
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return;
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}
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u8 SMBus_ReceiveBit(void)
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{
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u8 Ack_bit;
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SMBUS_SDA_H(); //?????????,????
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SMBus_Delay(2); // High Level of Clock Pulse
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SMBUS_SCK_H(); // Set SCL line
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SMBus_Delay(5); // High Level of Clock Pulse
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if (SMBUS_SDA_PIN())
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{
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Ack_bit=1;
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}
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else
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{
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Ack_bit=0;
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}
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SMBUS_SCK_L(); // Clear SCL line
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SMBus_Delay(3); // Low Level of Clock Pulse
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return Ack_bit;
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}
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u8 SMBus_ReceiveByte(u8 ack_nack)
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{
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u8 RX_buffer;
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u8 Bit_Counter;
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for(Bit_Counter=8; Bit_Counter; Bit_Counter--)
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{
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if(SMBus_ReceiveBit()) // Get a bit from the SDA line
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{
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RX_buffer <<= 1; // If the bit is HIGH save 1 in RX_buffer
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RX_buffer |=0x01;
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}
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else
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{
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RX_buffer <<= 1; // If the bit is LOW save 0 in RX_buffer
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RX_buffer &=0xfe;
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}
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}
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SMBus_SendBit(ack_nack); // Sends acknowledgment bit
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return RX_buffer;
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}
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void SMBus_Delay(u16 time)
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{
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u16 i, j;
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for (i=0; i<4; i++)
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{
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for (j=0; j<time; j++);
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}
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}
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void SMBus_Init()
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{
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GPIO_InitTypeDef GPIO_InitStructure;
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RCC_APB2PeriphClockCmd(RCC_APB2Periph_SMBUS_PORT, ENABLE);
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GPIO_InitStructure.GPIO_Pin = SMBUS_SCK | SMBUS_SDA;
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GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
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GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
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GPIO_Init(SMBUS_PORT, &GPIO_InitStructure);
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SMBUS_SCK_H();
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SMBUS_SDA_H();
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}
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u16 SMBus_ReadMemory(u8 slaveAddress, u8 command)
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{
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u16 data;
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u8 Pec;
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u8 DataL=0;
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u8 DataH=0;
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u8 arr[6];
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u8 PecReg;
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u8 ErrorCounter;
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ErrorCounter=0x00;
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slaveAddress <<= 1;
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do
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{
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repeat:
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SMBus_StopBit();
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--ErrorCounter; //Pre-decrement ErrorCounter
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if(!ErrorCounter) //ErrorCounter=0?
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{
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break; //Yes,go out from do-while{}
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}
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SMBus_StartBit(); //Start condition
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if(SMBus_SendByte(slaveAddress))//Send SlaveAddress ???Wr=0????????
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{
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goto repeat; //Repeat comunication again
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}
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if(SMBus_SendByte(command)) //Send command
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{
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goto repeat; //Repeat comunication again
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}
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SMBus_StartBit(); //Repeated Start condition
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if(SMBus_SendByte(slaveAddress+1)) //Send SlaveAddress ???Rd=1????????
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{
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goto repeat; //Repeat comunication again
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}
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DataL = SMBus_ReceiveByte(ACK); //Read low data,master must send ACK
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DataH = SMBus_ReceiveByte(ACK); //Read high data,master must send ACK
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Pec = SMBus_ReceiveByte(NACK); //Read PEC byte, master must send NACK
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SMBus_StopBit(); //Stop condition
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arr[5] = slaveAddress; //
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arr[4] = command; //
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arr[3] = slaveAddress+1; //Load array arr
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arr[2] = DataL; //
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arr[1] = DataH; //
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arr[0] = 0; //
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PecReg=PEC_Calculation(arr);//Calculate CRC
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}
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while(PecReg != Pec); //If received and calculated CRC are equal go out from do-while{}
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data = (DataH<<8) | DataL; //data=DataH:DataL
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return data;
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}
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u8 PEC_Calculation(u8 pec[])
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{
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u8 crc[6];
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u8 BitPosition=47;
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u8 shift;
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u8 i;
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u8 j;
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u8 temp;
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do
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{
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/*Load pattern value 0x000000000107*/
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crc[5]=0;
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crc[4]=0;
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crc[3]=0;
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crc[2]=0;
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crc[1]=0x01;
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crc[0]=0x07;
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/*Set maximum bit position at 47 ( six bytes byte5...byte0,MSbit=47)*/
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BitPosition=47;
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/*Set shift position at 0*/
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shift=0;
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/*Find first "1" in the transmited message beginning from the MSByte byte5*/
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i=5;
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j=0;
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while((pec[i]&(0x80>>j))==0 && i>0)
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{
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BitPosition--;
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if(j<7)
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{
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j++;
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}
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else
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{
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j=0x00;
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i--;
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}
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}/*End of while */
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/*Get shift value for pattern value*/
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shift=BitPosition-8;
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/*Shift pattern value */
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while(shift)
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{
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for(i=5; i<0xFF; i--)
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{
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if((crc[i-1]&0x80) && (i>0))
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{
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temp=1;
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}
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else
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{
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temp=0;
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}
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crc[i]<<=1;
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crc[i]+=temp;
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}/*End of for*/
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shift--;
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}/*End of while*/
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/*Exclusive OR between pec and crc*/
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for(i=0; i<=5; i++)
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{
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pec[i] ^=crc[i];
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}/*End of for*/
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}
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while(BitPosition>8); /*End of do-while*/
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return pec[0];
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}
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float SMBus_ReadTemp(void)
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{
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float temp;
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temp = SMBus_ReadMemory(SA, RAM_ACCESS|RAM_TOBJ1)*0.02-273.15;
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return temp;
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}
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