Mikroelektronika MIKROE-350 Fiche De Données

The example demonstrates how to communicate with Port Expander MCP23S17.

Note that Port Expander pins A2 A1 A0 are connected to GND so Port Expander
Hardware Address is 0.

program PortExpander

' Port Expander module connections
dim SPExpanderRST as sbit at PORTB.B0

SPExpanderCS  

as sbit at PORTB.B1

SPExpanderRST_Direction 

as sbit at DDRB.B0

SPExpanderCS_Direction  

as sbit at DDRB.B1

' End Port Expander module connections

dim counter as byte' = 0

main:

counter = 0

DDRC = 0xFF                    ' Set PORTC as output

' If Port Expander Library uses SPI1 module
SPI1_Init()     ' Initialize SPI module used with PortExpander

Spi_Rd_Ptr = @SPI1_Read              ' Pass pointer to SPI Read

sub function of used SPI module

'  If Port Expander Library uses SPI2 module
'  SPI2_Init()    ' Initialize SPI module used with PortExpander

'  Spi_Rd_Ptr = @SPI2_Read             ' Pass pointer to SPI Read
sub function of used SPI module

Expander_Init(0)                ' Initialize Port Expander

Expander_Set_DirectionPortA(0, 0x00) ' Set Expander"s PORTA to be

output

Expander_Set_DirectionPortB(0,0xFF)  ' Set Expander"s PORTB to be

input

Expander_Set_PullUpsPortB(0,0xFF)    ' Set pull-ups to all of the

Expander"s PORTB pins

TRUE                        ' Endless loop

Expander_Write_PortA(0, counter)   ' Write i to expander"s PORTA

Inc(counter)

PORTC = Expander_Read_PortB(0)     ' Read expander"s PORTB and

write it to LEDs

Delay_ms(100)

300

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