The mikroPascal PRO for ARM 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.

• 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.
• LSB sent first.

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

Library Routines

• Soft_SPI_Init
• Soft_SPI_Read
• Soft_SPI_Write

Soft_SPI_Init

// DAC module connections
var SoftSpi_CLK : sbit at GPIO_PORTJ_DATA3_bit;
    SoftSpi_SDI : sbit at GPIO_PORTJ_DATA4_bit;
    SoftSpi_SDO : sbit at GPIO_PORTJ_DATA5_bit;

var SoftSpi_CLK_Direction : sbit at GPIO_PORTJ_DIR3_bit;
    SoftSpi_SDI_Direction : sbit at GPIO_PORTJ_DIR4_bit;
    SoftSpi_SDO_Direction : sbit at GPIO_PORTJ_DIR5_bit;
// End DAC module connections
...
Soft_SPI_Init(); // Init Soft_SPI

// DAC module connections
var SoftSpi_CLK : sbit at DIO_P6OUT.B2;
    SoftSpi_SDI : sbit at DIO_P6IN.B0;
    SoftSpi_SDO : sbit at DIO_P6OUT.B1;

var SoftSpi_CLK_Direction : sbit at DIO_P6DIR.B2;
    SoftSpi_SDI_Direction : sbit at DIO_P6DIR.B0;
    SoftSpi_SDO_Direction : sbit at DIO_P6DIR.B1;
// End DAC module connections
...
Soft_SPI_Init(); // Init Soft_SPI

// DAC module connections
var SoftSpi_CLK : sbit at GPIOD_ODR.B3;
    SoftSpi_SDI : sbit at GPIOD_ODR.B4;
    SoftSpi_SDO : sbit at GPIOD_ODR.B5;
// End DAC module connections
...
Soft_SPI_Init(); // Init Soft_SPI

// DAC module connections
var SoftSpi_CLK : sbit at GPIO_OUTPUT_150_157.B3;
    SoftSpi_SDI : sbit at GPIO_OUTPUT_050_057.B4;
    SoftSpi_SDO : sbit at GPIO_OUTPUT_160_167.B5;
// End DAC module connections
...
Soft_SPI_Init(); // Init Soft_SPI

Soft_SPI_Read

var data_read, data_send : byte;
...
// 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);

Soft_SPI_Write

// Write a byte to the Soft SPI bus
Soft_SPI_Write(0xAA);