| 0,0 → 1,261 |
|---|
| /************ SMB driver ************/ |
| |
| #define SA 0x00 // Slave Address (0 for single slave / 0x5A<<1 default) |
| #define RAM_Access 0x00 // RAM access command |
| #define RAM_Tobj1 0x07 // To1 address in the RAM |
| #define RAM_Tamb 0x06 // Ta address in the RAM |
| |
| |
| // High and Low level of clock |
| #define HIGHLEV 40 // max. 50us |
| #define LOWLEV 100 // max. 30ms |
| #define TBUF 20 |
| |
| // SMBus control signals |
| #define SCL PIN_B0 |
| #define SDA PIN_B1 |
| |
| #define mSDA_HIGH() output_float(SDA); // SDA float |
| #define mSDA_LOW() output_low(SDA); // SDA low |
| #define mSCL_HIGH() output_float(SCL); // SCL float |
| #define mSCL_LOW() output_low(SCL); // SCL low |
| |
| #define ACK 0 |
| #define NACK 1 |
| |
| //********************************************************************************************** |
| // START CONDITION ON SMBus |
| //********************************************************************************************** |
| //Name: START_bit |
| //Function: Generate START condition on SMBus |
| //Parameters: No |
| //Return: No |
| //Comments: Refer to "System Managment BUS(SMBus) specification Version 2.0" |
| // or AN"SMBus communication with MLX90614" on the website www.melexis.com |
| //********************************************************************************************** |
| void SMB_START_bit(void) |
| { |
| // disable_interrupts(GLOBAL); |
| mSDA_HIGH(); // Set SDA line |
| delay_us( TBUF ); // Wait a few microseconds |
| mSCL_HIGH(); // Set SCL line |
| delay_us( TBUF ); // Generate bus free time between Stop |
| // and Start condition (Tbuf=4.7us min) |
| mSDA_LOW(); // Clear SDA line |
| delay_us( TBUF ); // Hold time after (Repeated) Start Condition. |
| // After this period, the first clock is generated. |
| // (Thd:sta=4.0us min) |
| mSCL_LOW(); // Clear SCL line |
| // enable_interrupts(GLOBAL); |
| delay_us( TBUF ); // Wait a few microseconds |
| } |
| |
| //********************************************************************************************* |
| // STOP CONDITION ON SMBus |
| //********************************************************************************************* |
| //Name: STOPbit |
| //Function: Generate STOP condition on SMBus |
| //Parameters: No |
| //Return: No |
| //Comments: Refer to "System Managment BUS(SMBus) specification Version 2.0" |
| // or AN"SMBus communication with MLX90614" on the website www.melexis.com |
| //********************************************************************************************* |
| void SMB_STOP_bit(void) |
| { |
| // disable_interrupts(GLOBAL); |
| mSDA_HIGH(); |
| mSCL_LOW(); // Clear SCL line |
| delay_us( TBUF ); // Wait a few microseconds |
| mSDA_LOW(); // Clear SDA line |
| delay_us( TBUF ); // Wait a few microseconds |
| mSCL_HIGH(); // Set SCL line |
| delay_us( TBUF ); // Stop condition setup time(Tsu:sto=4.0us min) |
| mSDA_HIGH(); // Set SDA line |
| // enable_interrupts(GLOBAL); |
| } |
| |
| |
| void SMB_send_bit(unsigned char bit_out) |
| { |
| // disable_interrupts(GLOBAL); |
| if(bit_out==0) {mSDA_LOW();} |
| else {mSDA_HIGH();} |
| delay_us(3); |
| mSCL_HIGH(); // Set SCL line |
| delay_us( HIGHLEV ); // High Level of Clock Pulse |
| mSCL_LOW(); // Clear SCL line |
| |
| //!!! toggle_dome(); |
| delay_us(1); |
| |
| delay_us( LOWLEV ); // Low Level of Clock Pulse |
| // mSDA_HIGH(); // Master release SDA line , |
| // enable_interrupts(GLOBAL); |
| |
| //!!! toggle_dome(); |
| delay_us(1); |
| return; |
| } |
| |
| unsigned char SMB_Receive_bit(void) |
| { |
| unsigned char Ack_bit; |
| |
| // disable_interrupts(GLOBAL); |
| mSDA_HIGH(); //_SDA_IO=1; // SDA-input |
| mSCL_HIGH(); // Set SCL line |
| delay_us( HIGHLEV ); // High Level of Clock Pulse |
| if(input(SDA)) Ack_bit=1; // \ Read acknowledgment bit, save it in Ack_bit |
| else Ack_bit=0; // / |
| mSCL_LOW(); // Clear SCL line |
| |
| //!!! toggle_dome(); |
| delay_us(1); |
| |
| delay_us( LOWLEV ); // Low Level of Clock Pulse |
| // enable_interrupts(GLOBAL); |
| |
| //!!! toggle_dome(); |
| delay_us(1); |
| |
| return Ack_bit; |
| } |
| |
| |
| //********************************************************************************************* |
| // TRANSMIT DATA ON SMBus |
| //********************************************************************************************* |
| //Name: TX_byte |
| //Function: Send a byte on SMBus |
| //Parameters: TX_buffer ( the byte which will be send on the SMBus ) |
| //Return: Ack_bit ( acknowledgment bit ) |
| //Comments: Sends MSbit first |
| //********************************************************************************************* |
| unsigned char SMB_TX_byte(unsigned char Tx_buffer) |
| { |
| unsigned char Bit_counter; |
| unsigned char Ack_bit; |
| unsigned char 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 |
| |
| SMB_send_bit(bit_out); // Send the current bit on SDA |
| Tx_buffer<<=1; // Get next bit for checking |
| } |
| |
| Ack_bit=SMB_Receive_bit(); // Get acknowledgment bit |
| |
| return Ack_bit; |
| } |
| |
| //********************************************************************************************* |
| // RECEIVE DATA ON SMBus |
| //********************************************************************************************* |
| //Name: RX_byte |
| //Function: Receive a byte on SMBus |
| //Parameters: ack_nack (ackowlegment bit) |
| //Return: RX_buffer(Received byte) |
| //Comments: MSbit is received first |
| //********************************************************************************************* |
| unsigned char SMB_RX_byte(unsigned char ack_nack) |
| { |
| unsigned char RX_buffer; |
| unsigned char Bit_Counter; |
| |
| for(Bit_Counter=8; Bit_Counter; Bit_Counter--) |
| { |
| if(SMB_Receive_bit()) // Get a bit from the SDA line |
| { |
| RX_buffer <<= 1; // If the bit is HIGH save 1 in RX_buffer |
| RX_buffer |=0b00000001; |
| } |
| else |
| { |
| RX_buffer <<= 1; // If the bit is LOW save 0 in RX_buffer |
| RX_buffer &=0b11111110; |
| } |
| } |
| |
| SMB_send_bit(ack_nack); // Sends acknowledgment bit |
| |
| return RX_buffer; |
| } |
| |
| |
| unsigned char PEC_calculation(unsigned char pec[]) // CRC calculation |
| { |
| unsigned char crc[6]; |
| unsigned char BitPosition=47; |
| unsigned char shift; |
| unsigned char i; |
| unsigned char j; |
| unsigned char temp; |
| |
| do |
| { |
| crc[5]=0; /* Load CRC value 0x000000000107 */ |
| crc[4]=0; |
| crc[3]=0; |
| crc[2]=0; |
| crc[1]=0x01; |
| crc[0]=0x07; |
| BitPosition=47; /* Set maximum bit position at 47 */ |
| shift=0; |
| |
| //Find first 1 in the transmited message |
| i=5; /* Set highest index */ |
| j=0; |
| while((pec[i]&(0x80>>j))==0 && i>0) |
| { |
| BitPosition--; |
| if(j<7) |
| { |
| j++; |
| } |
| else |
| { |
| j=0x00; |
| i--; |
| } |
| //!!! toggle_dome(); |
| delay_us(1); |
| |
| } |
| |
| shift=BitPosition-8; /*Get shift value for crc value*/ |
| |
| |
| //Shift crc value |
| while(shift) |
| { |
| for(i=5; i<0xFF; i--) |
| { |
| if((crc[i-1]&0x80) && (i>0)) |
| { |
| temp=1; |
| } |
| else |
| { |
| temp=0; |
| } |
| crc[i]<<=1; |
| crc[i]+=temp; |
| } |
| shift--; |
| //!!! toggle_dome(); |
| delay_us(1); |
| |
| } |
| |
| //Exclusive OR between pec and crc |
| for(i=0; i<=5; i++) |
| { |
| pec[i] ^=crc[i]; |
| } |
| } while(BitPosition>8); |
| |
| return pec[0]; |
| } |