Software SPI Library

The mikroC PRO for FT90x provides routines for implementing Software SPI communication. These routines are hardware independent and can be used with any MCU. The Software SPI Library provides easy communication with other devices via SPI: A/D converters, D/A converters, MAX7219, LTC1290, etc.

Library configuration:

SPI to Master mode
Clock value = 20 kHz.
Data sampled at the middle of interval.
Clock idle state low.
Data sampled at the middle of interval.
Data transmitted at low to high edge.

The library configures SPI to the master mode, clock = 20kHz, data sampled at the middle of interval, clock idle state low and data transmitted at low to high edge.

Important : The Software SPI library implements time-based activities, so interrupts need to be disabled when using it.

External dependencies of Software SPI Library

The following variables must be defined in all projects using Software SPI Library:	Description :	Example :
`extern sfr sbit SoftSpi_SDI;`	Data In line.	`sbit SoftSpi_SDI at GPIO_PIN30_Bit;`
`extern sfr sbit SoftSpi_SDO;`	Data Out line.	`sbit SoftSpi_SDO at GPIO_PIN29_bit;`
`extern sfr sbit SoftSpi_CLK;`	Clock line.	`sbit SoftSpi_CLK at GPIO_PIN27_bit;`

Soft_SPI_Init

Prototype	void Soft_SPI_Init();
Description	Routine initializes the software SPI 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 SPI module connections sbit SoftSpi_CLK at GPIO_PIN27_bit; sbit SoftSpi_SDI at GPIO_PIN30_Bit; sbit SoftSpi_SDO at GPIO_PIN29_bit; // End Software SPI module connections ... Soft_SPI_Init(); // Initialize Soft_SPI
Notes	None.

Soft_SPI_Read

Prototype	unsigned short Soft_SPI_Read(char sdata);
Description	This routine performs 3 operations simultaneously. It provides clock for the Software SPI bus, reads a byte and sends a byte.
Parameters	`sdata:` data to be sent.
Returns	Byte received via the SPI bus.
Requires	Soft SPI must be initialized before using this function. See Soft_SPI_Init routine.
Example	unsigned short data_read; char data_send; ... // Read a byte and assign it to data_read variable // (data_send byte will be sent via SPI during the Read operation) data_read = Soft_SPI_Read(data_send);
Notes	None.

Soft_SPI_Write

Prototype	void Soft_SPI_Write(char sdata);
Description	This routine sends one byte via the Software SPI bus.
Parameters	`sdata:` data to be sent.
Returns	Nothing.
Requires	Soft SPI must be initialized before using this function. See Soft_SPI_Init.
Example	// Write a byte to the Soft SPI bus Soft_SPI_Write(0xAA);
Notes	None.

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