Extend I/O Ports using PIC Microcontroller

• hardware addressing enabled
• automatic address pointer incrementing disabled (byte mode)
• BANK_0 register adressing
• slew rate enabled

Parameters :

• ModuleAddress: Port Expander hardware address, see schematic at the bottom of this page

• SPExpanderCS: Chip Select line
• SPExpanderRST: Reset line
• SPExpanderCS_Direction: Direction of the Chip Select pin
• SPExpanderRST_Direction: Direction of the Reset pin

must be defined before using this function.
SPI module needs to be initialized. See SPIx_Init and SPIx_Init_Advanced routines.

// Port Expander module connections
sbit  SPExpanderRST at RC0_bit;
sbit  SPExpanderCS  at RC1_bit;
sbit  SPExpanderRST_Direction at TRISC0_bit;
sbit  SPExpanderCS_Direction  at TRISC1_bit;
// End Port Expander module connections

...

ANSEL  = 0;               // Configure AN pins as digital I/O
ANSELH = 0;

// If Port Expander Library uses SPI module
SPI1_Init();               // Initialize SPI module used with PortExpander
Expander_Init(0);         // Initialize Port Expander

• rstPort: Port Expander's reset port
• rstPin: Port Expander's reset pin
• haen: Enable hardware addressing. Valid values :
  • 0 - hardware addressing disabled
  • 1 - hardware addressing enabled

• SPExpanderCS: Chip Select line
• SPExpanderRST: Reset line
• SPExpanderCS_Direction: Direction of the Chip Select pin
• SPExpanderRST_Direction: Direction of the Reset pin

must be defined before using this function.

// Port Expander module connections
sbit  SPExpanderRST at RC0_bit;
sbit  SPExpanderCS  at RC1_bit;
sbit  SPExpanderRST_Direction at TRISC0_bit;
sbit  SPExpanderCS_Direction  at TRISC1_bit;
// End Port Expander module connections

...

ANSEL  = 0;               // Configure AN pins as digital I/O
ANSELH = 0;

// If Port Expander Library uses SPI module
SPI1_Init();              // Initialize SPI module used with PortExpander
Expander_Init_Advanced(&PORTB, 0, 0);         // Initialize Port Expander

• ModuleAddress: Port Expander hardware address, see schematic at the bottom of this page
• RegAddress: Port Expander's internal register address

// Read a byte from Port Expander's register
char read_data;
...
read_data = Expander_Read_Byte(0,1);

• ModuleAddress: Port Expander hardware address, see schematic at the bottom of this page
• RegAddress: Port Expander's internal register address
• Data_: data to be written

// Write a byte to the Port Expander's register
Expander_Write_Byte(0,1,0xFF);

• ModuleAddress: Port Expander hardware address, see schematic at the bottom of this page

Port Expander's PortA should be configured as input.

// Read a byte from Port Expander's PORTA
char read_data;
...
Expander_Set_DirectionPortA(0,0xFF);        // set expander's porta to be input
...
read_data = Expander_Read_PortA(0);

• ModuleAddress: Port Expander hardware address, see schematic at the bottom of this page

Port Expander's PortB should be configured as input.

// Read a byte from Port Expander's PORTB
char read_data;
...
Expander_Set_DirectionPortB(0,0xFF);        // set expander's portb to be input
...
read_data = Expander_Read_PortB(0);