twi.c File Reference

#include "chip.h"
#include <assert.h>

Macros
#define	TWIHS_IT

Functions
void	TWI_ConfigureMaster (Twihs *pTwi, uint32_t dwTwCk, uint32_t dwMCk)
	Configures a TWI peripheral to operate in master mode, at the given frequency (in Hz). The duty cycle of the TWI clock is set to 50%. More...
void	TWI_ConfigureSlave (Twihs *pTwi, uint8_t slaveAddress)
	Configures a TWI peripheral to operate in slave mode. More...
void	TWI_Stop (Twihs *pTwi)
	Sends a STOP condition on the TWI. More...
void	TWI_StartRead (Twihs *pTwi, uint8_t address, uint32_t iaddress, uint8_t isize)
	Starts a read operation on the TWI bus with the specified slave, it returns immediately. Data must then be read using TWI_ReadByte() whenever a byte is available (poll using TWI_ByteReceived()). More...
uint8_t	TWI_ReadByte (Twihs *pTwi)
	Reads a byte from the TWI bus. The read operation must have been started using TWI_StartRead() and a byte must be available (check with TWI_ByteReceived()). More...
void	TWI_WriteByte (Twihs *pTwi, uint8_t byte)
	Sends a byte of data to one of the TWI slaves on the bus. More...
void	TWI_StartWrite (Twihs *pTwi, uint8_t address, uint32_t iaddress, uint8_t isize, uint8_t byte)
	Starts a write operation on the TWI to access the selected slave, then returns immediately. A byte of data must be provided to start the write; other bytes are written next. after that to send the remaining bytes. More...
uint8_t	TWI_ByteReceived (Twihs *pTwi)
	Check if a byte have been received from TWI. More...
uint8_t	TWI_ByteSent (Twihs *pTwi)
	Check if a byte have been sent to TWI. More...
uint8_t	TWI_TransferComplete (Twihs *pTwi)
	Check if current transmission is completed. More...
void	TWI_EnableIt (Twihs *pTwi, uint32_t sources)
	Enables the selected interrupts sources on a TWI peripheral. More...
void	TWI_DisableIt (Twihs *pTwi, uint32_t sources)
	Disables the selected interrupts sources on a TWI peripheral. More...
uint32_t	TWI_GetStatus (Twihs *pTwi)
	Get the current status register of the given TWI peripheral. More...
uint32_t	TWI_GetMaskedStatus (Twihs *pTwi)
	Returns the current status register of the given TWI peripheral, but masking interrupt sources which are not currently enabled. More...
void	TWI_SendSTOPCondition (Twihs *pTwi)
	Sends a STOP condition. STOP Condition is sent just after completing the current byte transmission in master read mode. More...

Variables
uint32_t	twi_send_stop = 0

Detailed Description

Implementation of Two Wire Interface (TWI).

Macro Definition Documentation

TWIHS_IT

#define TWIHS_IT

Value:

(TWIHS_IER_TXCOMP | TWIHS_IER_TXCOMP | TWIHS_IER_RXRDY \
                      | TWIHS_IER_TXRDY | TWIHS_IER_SVACC | TWIHS_IER_GACC | \
                      TWIHS_IER_OVRE | TWIHS_IER_UNRE | TWIHS_IER_NACK | \
                      TWIHS_IER_ARBLST | TWIHS_IER_SCL_WS | TWIHS_IER_EOSACC | \
                      TWIHS_IER_MCACK | TWIHS_IER_TOUT | TWIHS_IER_PECERR |\
                      TWIHS_IER_SMBDAM | TWIHS_IER_SMBHHM)

Function Documentation

TWI_ByteReceived()

uint8_t TWI_ByteReceived

(

Twihs *

pTwi

)

Check if a byte have been received from TWI.

Parameters

pTwi	Pointer to an Twihs instance.

Returns

1 if a byte has been received and can be read on the given TWI peripheral; otherwise, returns 0. This function resets the status register.

TWI_ByteSent()

uint8_t TWI_ByteSent

(

Twihs *

pTwi

)

Check if a byte have been sent to TWI.

Parameters

pTwi	Pointer to an Twihs instance.

Returns

1 if a byte has been sent so another one can be stored for transmission; otherwise returns 0. This function clears the status register.

TWI_ConfigureMaster()

void TWI_ConfigureMaster	(	Twihs *	pTwi,
		uint32_t	dwTwCk,
		uint32_t	dwMCk
	)

Configures a TWI peripheral to operate in master mode, at the given frequency (in Hz). The duty cycle of the TWI clock is set to 50%.

Parameters

pTwi	Pointer to an Twihs instance.
twck	Desired TWI clock frequency.
mck	Master clock frequency.

TWI_ConfigureSlave()

void TWI_ConfigureSlave	(	Twihs *	pTwi,
		uint8_t	slaveAddress
	)

Configures a TWI peripheral to operate in slave mode.

Parameters

pTwi	Pointer to an Twihs instance.
slaveAddress	Slave address.

TWI_DisableIt()

void TWI_DisableIt	(	Twihs *	pTwi,
		uint32_t	sources
	)

Disables the selected interrupts sources on a TWI peripheral.

Parameters

pTwi	Pointer to an Twihs instance.
sources	Bitwise OR of selected interrupt sources.

TWI_EnableIt()

void TWI_EnableIt	(	Twihs *	pTwi,
		uint32_t	sources
	)

Enables the selected interrupts sources on a TWI peripheral.

Parameters

pTwi	Pointer to an Twihs instance.
sources	Bitwise OR of selected interrupt sources.

TWI_GetMaskedStatus()

uint32_t TWI_GetMaskedStatus

(

Twihs *

pTwi

)

Returns the current status register of the given TWI peripheral, but masking interrupt sources which are not currently enabled.

Note

This resets the internal value of the status register, so further read may yield different values.

Parameters

pTwi	Pointer to an Twihs instance.

TWI_GetStatus()

uint32_t TWI_GetStatus

(

Twihs *

pTwi

)

Get the current status register of the given TWI peripheral.

Note

This resets the internal value of the status register, so further read may yield different values.

Parameters

pTwi	Pointer to an Twihs instance.

Returns

TWI status register.

TWI_ReadByte()

uint8_t TWI_ReadByte

(

Twihs *

pTwi

)

Reads a byte from the TWI bus. The read operation must have been started using TWI_StartRead() and a byte must be available (check with TWI_ByteReceived()).

Parameters

pTwi	Pointer to an Twihs instance.

Returns

byte read.

TWI_SendSTOPCondition()

void TWI_SendSTOPCondition

(

Twihs *

pTwi

)

Sends a STOP condition. STOP Condition is sent just after completing the current byte transmission in master read mode.

Parameters

pTwi	Pointer to an Twihs instance.

TWI_StartRead()

void TWI_StartRead	(	Twihs *	pTwi,
		uint8_t	address,
		uint32_t	iaddress,
		uint8_t	isize
	)

Starts a read operation on the TWI bus with the specified slave, it returns immediately. Data must then be read using TWI_ReadByte() whenever a byte is available (poll using TWI_ByteReceived()).

Parameters

pTwi	Pointer to an Twihs instance.
address	Slave address on the bus.
iaddress	Optional internal address bytes.
isize	Number of internal address bytes.

TWI_StartWrite()

void TWI_StartWrite	(	Twihs *	pTwi,
		uint8_t	address,
		uint32_t	iaddress,
		uint8_t	isize,
		uint8_t	byte
	)

Starts a write operation on the TWI to access the selected slave, then returns immediately. A byte of data must be provided to start the write; other bytes are written next. after that to send the remaining bytes.

Parameters

pTwi	Pointer to an Twihs instance.
address	Address of slave to acccess on the bus.
iaddress	Optional slave internal address.
isize	Number of internal address bytes.
byte	First byte to send.

TWI_Stop()

void TWI_Stop

(

Twihs *

pTwi

)

Sends a STOP condition on the TWI.

Parameters

pTwi	Pointer to an Twihs instance.

TWI_TransferComplete()

uint8_t TWI_TransferComplete

(

Twihs *

pTwi

)

Check if current transmission is completed.

Parameters

pTwi	Pointer to an Twihs instance.

Returns

1 if the current transmission is complete (the STOP has been sent); otherwise returns 0.

TWI_WriteByte()

void TWI_WriteByte	(	Twihs *	pTwi,
		uint8_t	byte
	)

Sends a byte of data to one of the TWI slaves on the bus.

Note

This function must be called once before TWI_StartWrite() with the first byte of data to send, then it shall be called repeatedly after that to send the remaining bytes.

Parameters

pTwi	Pointer to an Twihs instance.
byte	Byte to send.

Variable Documentation

twi_send_stop

uint32_t twi_send_stop = 0

variable for control thether or not to set both START and STOP In single data byte master read, the START and STOP must both be set