Mikroelektronika MIKROE-350 Datenbogen

This code demonstrates using library routines for Soft_SPI communication. Also, this
example demonstrates working with Microchip's MCP4921 12-bit D/A converter.

program Soft_SPI

' DAC module connections
dim Chip_Select as sbit at PORTB.0

SoftSpi_CLK 

as sbit at PORTB.7

SoftSpi_SDI 

as sbit at PINB.6   ' Note: Input signal

SoftSpi_SDO

as sbit at PORTB.5

dim Chip_Select_Direction as sbit at DDRB.0

SoftSpi_CLK_Direction 

as sbit at DDRB.7

SoftSpi_SDI_Direction 

as sbit at DDRB.6

SoftSpi_SDO_Direction 

as sbit at DDRB.5

' End DAC module connections

dim value as word

sub procedure InitMain()

DDA0_bit = 0                         ' Set PA0 pin as input
DDA1_bit = 0                         ' Set PA1 pin as input
Chip_Select = 1                      ' Deselect DAC

Chip_Select_Direction = 1             ' Set CS# pin as Output
Soft_Spi_Init()                      ' Initialize Soft_SPI

' DAC increments (0..4095) --> output voltage (0..Vref)
sub procedure DAC_Output(dim valueDAC as word)
dim temp as byte

Chip_Select = 0                        ' Select DAC chip
' Send High Byte

temp = 

word(valueDAC >> 8) and 0x0F    ' Store valueDAC[11..8] to

temp[3..0]

temp = temp or 0x30                    ' Define DAC setting, see

MCP4921 datasheet

Soft_SPI_Write(temp)        ' Send high byte via Soft SPI

' Send Low Byte
temp = valueDAC            ' Store valueDAC[7..0] to temp[7..0]

Soft_SPI_Write(temp)       ' Send low byte via Soft SPI

Chip_Select = 1                        ' Deselect DAC chip

main:

InitMain()                     ' Perform main initialization

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