A basic I2C driver. More...

#include <i2c.h>

Collaboration diagram for I2C:

Public Member Functions
void	Init (const int scl=28, const int sda=29, const int frequency=400000)
	Setup the DIRA, OUTA, and INA registers for scl and sda. More...

bool	Ping (const unsigned char device)
	Test for the Acknowledge of a device by sending start and the slave address. More...

bool	Put (const unsigned char device, const unsigned char address, const char byte)
	Put a single byte with the following format: More...

unsigned char	Get (const unsigned char device, const unsigned char address)
	Get a single byte with the following format: More...

bool	Put (const unsigned char device, const unsigned char address, const char *bytes, const int size)
	Put multiple bytes with the following format: More...

bool	Get (const unsigned char device, const unsigned char address, char *bytes, const int size)
	Get multiple bytes with the following format: More...

bool	Put (const unsigned char device, const char byte)
	Put a single byte, no register address, on the bus with the following format : More...

bool	Get (const unsigned char device, char *bytes, const int size)
	Get multiple bytes, no register address, on the bus with the following format: More...

void	Start ()
	Passthrough to base. More...

void	Stop ()
	Passthrough to base. More...

int	SendByte (const unsigned char byte)
	Passthrough to base. More...

unsigned char	ReadByte (const int acknowledge)
	Passthrough to base. More...

Public Attributes
I2CBase	base_

Detailed Description

A basic I2C driver.

All "device" fields should be the 7 bit address of the device, with the low bit set to 0 (the 7 addres bits are the upper bits). This applies to both the Put (write) and Get (read) cases.

Put and Get are based on I2C communication specification as described by ST in the LSM303DLHC and L3GD20 datasheets. Terms:

ST - Start
SAD - Slave Address (device)
SAK - Slave Acknowledge
SUB - SubAddress (slave register address)
SP - Stop
+W - plus write (lowest device bit set to 0)
+R - plus read (lowest device bit set to 1)
NMAK - Master No Acknowledge

I2C differs based on the device that you use. For functions that might be device specific, there is a reference indicator. These references are:

ST - ST Microelectronics, particularly the LSM303DLHC and L3GD20 devices.
MS - Measurement Specialties, particularly the MS5607 and MS5611 devices.

If you're using the multibyte Get and Put with ST based devices, be sure to bitwise OR the register address with 0x80 (the MSb to 1) in order to turn on the auto-increment function (see datasheet for L3GD20 for example). This is not done automatically by this library.

Author: SRLM

Member Function Documentation

unsigned char I2C::Get	(	const unsigned char	device,
		const unsigned char	address
	)

inline

Get a single byte with the following format:

+-----—+-—+----—+--—+--—+--—+-—+----—+--—+---—+---—+-—+ | Master | ST | SAD+W | | SUB | | ST | SAD+R | | | NMAK | SP | | Slave | | | SAK | | SAK | | | SAK | DATA | | | +-----—+-—+----—+--—+--—+--—+-—+----—+--—+---—+---—+-—+

Reference: ST

Parameters

device	the 7 bit slave I2C address (in bits 7-1, with bit 0 set to 0)
address	the 8 bit slave register address

Returns: the 8 bits of data read from register address.

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bool I2C::Get	(	const unsigned char	device,
		const unsigned char	address,
		char *	bytes,
		const int	size
	)

inline

Get multiple bytes with the following format:

                                                        |Repeat for # of bytes -1 | Last byte   |

+-----—+-—+----—+--—+--—+--—+-—+----—+--—+---—+--—+---—+--—+---—+---—+-—+ | Master | ST | SAD+W | | SUB | | ST | SAD+R | | | MAK | | MAK | | NMAK | SP | | Slave | | | SAK | | SAK | | | SAK | DATA | | DATA | | DATA | | | +-----—+-—+----—+--—+--—+--—+-—+----—+--—+---—+--—+---—+--—+---—+---—+-—+

Reference: ST

Parameters

device	the 7 bit slave I2C address (in bits 7-1, with bit 0 set to 0).
address	the 8 bit slave register address.
bytes	the address to begin storing the read bytes at.
size	the number of bytes to read.

Returns: false if one or more nAcks is received, true otherwise

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bool I2C::Get	(	const unsigned char	device,
		char *	bytes,
		const int	size
	)

inline

Get multiple bytes, no register address, on the bus with the following format:

                         |Repeat      |

+-----—+-—+----—+--—+---—+--—+---—+---—+-—+ | Master | ST | SAD+R | | | MAK | | NMAK | SP | | Slave | | | SAK | DATA | | DATA | | | +-----—+-—+----—+--—+---—+--—+---—+---—+-—+

Warning: Notice the lack of a specified register!

Reference: MS

Parameters

device	the 7 bit slave I2C address (in bits 7-1, with bit 0 set to 0)
bytes	the address to begin storing the read bytes at.
size	the number of bytes to read.

Returns: false if one or more nAcks is received, true otherwise

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void I2C::Init	(	const int	scl = `28`,
		const int	sda = `29`,
		const int	frequency = `400000`
	)

inline

Setup the DIRA, OUTA, and INA registers for scl and sda.

Parameters

scl	The I2C SCL pin. Defaults to the Propeller default SCL pin.
sda	The I2C SDA pin. Defaults to the Propeller default SDA pin.
frequency	The frequency in hz to run the bus at.

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bool I2C::Ping ( const unsigned char device)

inline

Test for the Acknowledge of a device by sending start and the slave address.

Useful for polling the bus and seeing what devices are available. Ping uses the following format:

+-----—+-—+----—+--—+-—+ | Master | ST | SAD+W | | SP | | Slave | | | SAK | | +-----—+-—+----—+--—+-—+

Returns: true if ack was received, false otherwise.

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bool I2C::Put	(	const unsigned char	device,
		const unsigned char	address,
		const char	byte
	)

inline

Put a single byte with the following format:

+-----—+-—+----—+--—+--—+--—+---—+--—+-—+ | Master | ST | SAD+W | | SUB | | BYTE | | SP | | Slave | | | SAK | | SAK | | SAK | | +-----—+-—+----—+--—+--—+--—+---—+--—+-—+

Reference: ST

Parameters

device	the 7 bit slave I2C address (in bits 7-1, with bit 0 set to 0)
address	the 8 bit slave register address
byte	the 8 bits of data to store at address.

Returns: false if one or more nAcks is received, true otherwise

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bool I2C::Put	(	const unsigned char	device,
		const unsigned char	address,
		const char *	bytes,
		const int	size
	)

inline

Put multiple bytes with the following format:

                                     |Repeat for # of bytes    |

+-----—+-—+----—+--—+--—+--—+---—+--—+---—+--—+-—+ | Master | ST | SAD+W | | SUB | | DATA | | DATA | | SP | | Slave | | | SAK | | SAK | | SAK | | SAK | | +-----—+-—+----—+--—+--—+--—+---—+--—+---—+--—+-—+

Reference: ST

Parameters

device	the 7 bit slave I2C address (in bits 7-1, with bit 0 set to 0)
address	the 8 bit slave register address
bytes	the set of bytes to store on device, starting at register address.
size	the number of bytes to write