I2C Functions

Data Structures
struct	i2c_address
Defines
#define	I2C_ARBITRATION_LOST   7
#define	I2C_BUSY   1
#define	I2C_CONT_NACK_ON_ADDR   1
#define	I2C_CONT_NACK_ON_DATA   2
#define	I2C_DEVICE_NOT_PRESENT   6
#define	I2C_ERR   2
#define	I2C_INIT_ERROR   10
#define	I2C_MAX_RETRY   11
#define	I2C_NACK_ON_ADDRESS   5
#define	I2C_NACK_ON_DATA   4
#define	I2C_NO_DATA   3
#define	I2C_NOBUS   12
#define	I2C_SLAVE_ERROR   9
#define	I2C_TIME_OUT   8
Typedefs
typedef i2c_address	i2c_addr_t
Functions
int32_t	i2c_init (u_int16_t mode)
int32_t	i2c_init_clock (u_int16_t mode, u_int8_t frequency)
	initialse and reset the i2c controller and set i2c clock
void	i2c_perror (int rc, char *msg)
	print and i2c error message
int32_t	i2c_read_rbt (u_int32_t addr, u_int8_t *buf, u_int32_t count, u_int32_t *bytecount, u_int32_t *flag)
int32_t	i2c_scan (u_int32_t addr, u_int8_t dir)
	scan for an i2c device
int32_t	i2c_write_rbt (u_int32_t addr, u_int8_t *buf, u_int32_t count, u_int32_t *bytecount, u_int32_t *flag)
int32_t	i2c_writeread_rbt (u_int32_t addr, u_int8_t *wbuf, u_int32_t wcount, u_int8_t *rbuf, u_int32_t rcount, u_int32_t *flag)
	write to i2c device issued a repeated start condition then read

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Define Documentation

#define I2C_ARBITRATION_LOST   7

err: Device not present

#define I2C_BUSY   1

transfer ended No Errors

#define I2C_CONT_NACK_ON_ADDR   1

ignore NACK from slave on address byte

#define I2C_CONT_NACK_ON_DATA   2

ignore NACK from slave on data byte

#define I2C_DEVICE_NOT_PRESENT   6

err: No ack on address

#define I2C_ERR   2

transfer busy

#define I2C_INIT_ERROR   10

err: Slave mode error

#define I2C_MAX_RETRY   11

err: Initialization (not done)

#define I2C_NACK_ON_ADDRESS   5

err: No ack on data

#define I2C_NACK_ON_DATA   4

err: No data in block

#define I2C_NO_DATA   3

err: general error

#define I2C_NOBUS   12

exceeded maximal number of retries

#define I2C_SLAVE_ERROR   9

err: Time out occurred

#define I2C_TIME_OUT   8

err: Arbitration lost

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Typedef Documentation

typedef struct i2c_address i2c_addr_t

full i2c address with channel and bus address

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Function Documentation

int32_t i2c_init (  u_int16_t  mode  )

initialise and reset the i2c controller Parameters: mode  master or slave. Use 0 for master Bug: slave mode is not supported yet. Putting the controller in slave mode will work. But an external master will not be able to write to the glue-card

int32_t i2c_init_clock (  u_int16_t  mode, u_int8_t  frequency )

initialse and reset the i2c controller and set i2c clock Parameters: mode  i2c_init frequency  i2c clock frequency according to PCF8845 data sheet

void i2c_perror (  int  rc, char *  msg )

print and i2c error message This is an emulation of the standard perror function. Since there is no global i2c error variable (this is maybe a design flaw), the status value must be passed. Parameters: rc  the return code of an i2c function *msg  a message to be prepended

int32_t i2c_read_rbt (  u_int32_t  addr, u_int8_t *  buf, u_int32_t  count, u_int32_t *  bytecount, u_int32_t *  flag )

read bytes from i2c Parameters: addr  i2c_address *buf  buffer for bytes to read count  number of bytes to read *bytecount  number of bytes actually read *flag  is an OR of I2C_CONT_NACK_ON_ADDR and I2C_CONT_NACK_ON_DATA. The respective conditions will be ignored. On return *flag will have the bits set if the ignored condition has been encountered during processing.

int32_t i2c_scan (  u_int32_t  addr, u_int8_t  dir )

scan for an i2c device Parameters: addr  i2c_address dir  can be I2C_SCAN_READ or I2C_SCAN_WRITE (usally WRITE works better)

int32_t i2c_write_rbt (  u_int32_t  addr, u_int8_t *  buf, u_int32_t  count, u_int32_t *  bytecount, u_int32_t *  flag )

write bytes to i2c Parameters: addr  i2c_address *buf  buffer with bytes to write count  number of bytes to write *bytecount  number of bytes actually written *flag  is an OR of I2C_CONT_NACK_ON_ADDR and I2C_CONT_NACK_ON_DATA. The respective conditions will be ignored. On return *flag will have the bits set if the ignored condition has been encountered during processing.

int32_t i2c_writeread_rbt (  u_int32_t  addr, u_int8_t *  wbuf, u_int32_t  wcount, u_int8_t *  rbuf, u_int32_t  rcount, u_int32_t *  flag )

write to i2c device issued a repeated start condition then read Bug: This might not be flexible enough for all situations (multiple repeats) Parameters: addr  i2c_address *wbuf  buffer with bytes to write wcount  number of bytes to write *rbuf  buffer for bytes to be read rcount  number of bytes to be read *flag  is an OR of I2C_CONT_NACK_ON_ADDR and I2C_CONT_NACK_ON_DATA. The respective conditions will be ignored. On return *flag will have the bits set if the ignored condition has been encountered during processing.

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