/* * TWIlib.h * * Created: 6/01/2014 10:38:42 PM * Author: Chris Herring */ #ifndef TWILIB_H_ #define TWILIB_H_ // TWI bit rate #define TWI_FREQ 400000 // Get TWI status #define TWI_STATUS (TWSR & 0xF8) // Transmit buffer length #define TXMAXBUFLEN 20 // Receive buffer length #define RXMAXBUFLEN 20 // Global transmit buffer volatile uint8_t *TWITransmitBuffer; // Global receive buffer volatile uint8_t TWIReceiveBuffer[RXMAXBUFLEN]; // Buffer indexes volatile int TXBuffIndex; // Index of the transmit buffer. Is volatile, can change at any time. int RXBuffIndex; // Current index in the receive buffer // Buffer lengths int TXBuffLen; // The total length of the transmit buffer int RXBuffLen; // The total number of bytes to read (should be less than RXMAXBUFFLEN) typedef enum { Ready, Initializing, RepeatedStartSent, MasterTransmitter, MasterReceiver, SlaceTransmitter, SlaveReciever } TWIMode; typedef struct TWIInfoStruct{ TWIMode mode; uint8_t errorCode; uint8_t repStart; }TWIInfoStruct; TWIInfoStruct TWIInfo; // TWI Status Codes #define TWI_START_SENT 0x08 // Start sent #define TWI_REP_START_SENT 0x10 // Repeated Start sent // Master Transmitter Mode #define TWI_MT_SLAW_ACK 0x18 // SLA+W sent and ACK received #define TWI_MT_SLAW_NACK 0x20 // SLA+W sent and NACK received #define TWI_MT_DATA_ACK 0x28 // DATA sent and ACK received #define TWI_MT_DATA_NACK 0x30 // DATA sent and NACK received // Master Receiver Mode #define TWI_MR_SLAR_ACK 0x40 // SLA+R sent, ACK received #define TWI_MR_SLAR_NACK 0x48 // SLA+R sent, NACK received #define TWI_MR_DATA_ACK 0x50 // Data received, ACK returned #define TWI_MR_DATA_NACK 0x58 // Data received, NACK returned // Miscellaneous States #define TWI_LOST_ARBIT 0x38 // Arbitration has been lost #define TWI_NO_RELEVANT_INFO 0xF8 // No relevant information available #define TWI_ILLEGAL_START_STOP 0x00 // Illegal START or STOP condition has been detected #define TWI_SUCCESS 0xFF // Successful transfer, this state is impossible from TWSR as bit2 is 0 and read only #define TWISendStart() (TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN)|(1<<TWIE)) // Send the START signal, enable interrupts and TWI, clear TWINT flag to resume transfer. #define TWISendStop() (TWCR = (1<<TWINT)|(1<<TWSTO)|(1<<TWEN)|(1<<TWIE)) // Send the STOP signal, enable interrupts and TWI, clear TWINT flag. #define TWISendTransmit() (TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWIE)) // Used to resume a transfer, clear TWINT and ensure that TWI and interrupts are enabled. #define TWISendACK() (TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWIE)|(1<<TWEA)) // FOR MR mode. Resume a transfer, ensure that TWI and interrupts are enabled and respond with an ACK if the device is addressed as a slave or after it receives a byte. #define TWISendNACK() (TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWIE)) // FOR MR mode. Resume a transfer, ensure that TWI and interrupts are enabled but DO NOT respond with an ACK if the device is addressed as a slave or after it receives a byte. // Function declarations void TWITransmitData(void *const TXdata, uint8_t dataLen, uint8_t repStart, uint8_t blocking); void TWIInit(void); uint8_t TWIReadData(uint8_t TWIaddr, uint8_t bytesToRead, uint8_t repStart); uint8_t isTWIReady(void); #endif // TWICOMMS_H_