Software I²C Library

The mikroC PRO for FT90x provides routines for implementing Software I²C communication. These routines are hardware independent and can be used with any MCU. The Software I²C library enables you to use MCU as Master in I²C communication. Multi-master mode is not supported.

  Important :

External dependencies of Software I²C Library

The following variables must be defined in all projects using Software I²C Library: Description : Example :
extern sbit Soft_I2C_Scl; Soft I²C Clock line. sbit Soft_I2C_Scl at GPIO_PIN26_bit;
extern sbit Soft_I2C_Sda; Soft I²C Data line. sbit Soft_I2C_Sda at GPIO_PIN25_bit;

Library Routines

Soft_I2C_Init

Prototype

void Soft_I2C_Init();

Description

Configures the software I²C module.

Parameters

None.

Returns

Nothing.

Requires

External dependencies of the library from the top of the page must be defined before using this function.

Example
// Software I2C connections
sbit Soft_I2C_Scl    at GPIO_PIN26_bit;
sbit Soft_I2C_Sda    at GPIO_PIN25_bit;
// End Software I2C connections
..
Soft_I2C_Init();           // Initialize Soft I2C communication
Notes

None.

Soft_I2C_Start

Prototype

void Soft_I2C_Start();

Description

Determines if the I²C bus is free and issues START signal.

Parameters

None.

Returns

Nothing.

Requires

Software I²C must be configured before using this function. See Soft_I2C_Init routine.

Example
// Issue START signal
Soft_I2C_Start();
Notes

None.

Soft_I2C_Read

Prototype

unsigned short Soft_I2C_Read(unsigned int ack);

Description

Reads one byte from the slave.

Parameters
  • ack: acknowledge signal parameter. If the ack==0 not acknowledge signal will be sent after reading, otherwise the acknowledge signal will be sent.
Returns

One byte from the Slave.

Requires

Soft I²C must be configured before using this function. See Soft_I2C_Init routine.

Also, START signal needs to be issued in order to use this function. See Soft_I2C_Start routine.

Example
unsigned short take;
...
// Read data and send the not_acknowledge signal
take = Soft_I2C_Read(0);
Notes

None.

Soft_I2C_Write

Prototype

unsigned short Soft_I2C_Write(unsigned short data_);

Description

Sends data byte via the I²C bus.

Parameters
  • data_: data to be sent
Returns
  • 0 if there were no errors.
  • 1 if write collision was detected on the I²C bus.
Requires

Soft I²C must be configured before using this function. See Soft_I2C_Init routine.

Also, START signal needs to be issued in order to use this function. See Soft_I2C_Start routine.

Example
unsigned short data_, error;
...
error = Soft_I2C_Write(data_);
error = Soft_I2C_Write(0xA3);
Notes

None.

Soft_I2C_Stop

Prototype

void Soft_I2C_Stop();

Description

Issues STOP signal.

Parameters

None.

Returns

Nothing.

Requires

Soft I²C must be configured before using this function. See Soft_I2C_Init routine.

Example
// Issue STOP signal
Soft_I2C_Stop();
Notes

None.

Soft_I2C_Break

Prototype

void Soft_I2C_Break();

Description

All Software I²C Library functions can block the program flow (see note at the top of this page). Calling this routine from interrupt will unblock the program execution. This mechanism is similar to WDT.

Parameters

None.

Returns

Nothing.

Requires Nothing.
Example

Notes

Interrupts should be disabled before using Software I²C routines again (see note at the top of this page).

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