forked from mirrors/qmk_firmware
82 lines
3.3 KiB
C
82 lines
3.3 KiB
C
|
/*
|
||
|
|
* TWIlib.h
|
||
|
|
*
|
||
|
|
* Created: 6/01/2014 10:38:42 PM
|
||
|
|
* Author: Chris Herring
|
||
|
|
* http://www.chrisherring.net/all/tutorial-interrupt-driven-twi-interface-for-avr-part1/
|
||
|
|
*/
|
||
|
|
|
||
|
|
|
||
|
|
#ifndef TWILIB_H_
|
||
|
|
#define TWILIB_H_
|
||
|
|
// TWI bit rate (was 100000)
|
||
|
|
#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
|
||
|
|
uint8_t TWITransmitBuffer[TXMAXBUFLEN];
|
||
|
|
// 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
|
||
|
|
uint8_t TWITransmitData(void *const TXdata, uint8_t dataLen, uint8_t repStart);
|
||
|
|
void TWIInit(void);
|
||
|
|
uint8_t TWIReadData(uint8_t TWIaddr, uint8_t bytesToRead, uint8_t repStart);
|
||
|
|
uint8_t isTWIReady(void);
|
||
|
|
|
||
|
|
#endif // TWICOMMS_H_
|