Port Expander Library

mikroPascal PRO for FT90x provides a library for communication with the Microchip’s Port Expander MCP23S17 via SPI interface.

Important :

The library uses the SPI module for communication. User must initialize the appropriate SPI module before using the Port Expander Library.
For MCUs with multiple SPI modules it is possible to initialize all of them and then switch by using the SPIM_Set_Active() function. See the SPI Library functions.
Library does not use Port Expander interrupts.

Library Dependency Tree

External dependencies of Port Expander Library

The following variables must be defined in all projects using Port Expander Library:	Description :	Example :
`var SPExpanderRST : sbit; sfr; external;`	Reset line.	`var SPExpanderRST : sbit at GPIO_PIN32_bit;`
`var SPExpanderCS : sbit; sfr; external;`	Chip Select line.	`var SPExpanderCS : sbit at GPIO_PIN31_bit;`

Library Routines

Expander_Init
Expander_Init_Advanced
Expander_Read_Byte
Expander_Write_Byte
Expander_Read_PortA
Expander_Read_PortB
Expander_Read_PortAB
Expander_Write_PortA
Expander_Write_PortB
Expander_Write_PortAB
Expander_SetBit_PortA
Expander_ClrBit_PortA
Expander_ToggleBit_PortA
Expander_SetBit_PortB
Expander_ClrBit_PortB
Expander_ToggleBit_PortB
Expander_Set_DirectionPortA
Expander_Set_DirectionPortB
Expander_Set_DirectionPortAB
Expander_Set_InputDirPortA
Expander_Set_OutputDirPortA
Expander_Set_InputDirPortB
Expander_Set_OutputDirPortB
Expander_Set_PullUpsPortA
Expander_Set_PullUpsPortB
Expander_Set_PullUpsPortAB
Expander_SetBits
Expander_ClrBits
Expander_ToggleBits

Expander_Init

Prototype	procedure Expander_Init(ModuleAddress : byte);
Description	Initializes Port Expander using SPI communication. Port Expander module settings : 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
Returns	Nothing.
Requires	External dependencies of the library from the top of the page must be defined before using this function. SPI module needs to be initialized. See SPIM1_Init and SPIM1_Init_Advanced routines.
Example	// Port Expander module connections var SPExpanderRST : sbit at GPIO_PIN32_bit; var SPExpanderCS : sbit at GPIO_PIN31_bit; ... SPIM1_Init(); Expander_Init(0); // Initialize Port Expander
Notes	None.

Expander_Init_Advanced

Prototype	procedure Expander_Init_Advanced(var rstPort : dword; rstPin : byte; haen : byte);
Description	Initializes Port Expander using SPI communication.
Parameters	`rstPort:` Port Expander's reset port `rstPin:` Port Expander's reset pin `haen:` Port Expander's hardware address
Returns	Nothing.
Requires	External dependencies of the library from the top of the page must be defined before using this function. SPI module needs to be initialized. See SPIM1_Init and SPIM1_Init_Advanced routines.
Example
Notes	None.

Expander_Read_Byte

Prototype	function Expander_Read_Byte(ModuleAddress, RegAddress : byte) : byte;
Description	The function reads byte from Port Expander.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `RegAddress:` Port Expander's internal register address
Returns	Byte read.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Read a byte from Port Expander's register var read_data : byte; ... read_data := Expander_Read_Byte(0,1);
Notes	None.

Expander_Write_Byte

Prototype	procedure Expander_Write_Byte(ModuleAddress, RegAddress, Data : byte);
Description	Routine writes a byte to Port Expander.
Parameters	`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
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Write a byte to the Port Expander's register Expander_Write_Byte(0,1,$FF);
Notes	None.

Expander_Read_PortA

Prototype	function Expander_Read_PortA(ModuleAddress : byte) : byte;
Description	The function reads byte from Port Expander's PortA.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page
Returns	Byte read.
Requires	Port Expander must be initialized. See Expander_Init. Port Expander's PortA should be configured as input. See Expander_Set_DirectionPortA and Expander_Set_DirectionPortAB routines.
Example	// Read a byte from Port Expander's PORTA var read_data : byte; ... Expander_Set_DirectionPortA(0,$FF); // set expander's porta to be input ... read_data := Expander_Read_PortA(0);
Notes	None.

Expander_Read_PortB

Prototype	function Expander_Read_PortB(ModuleAddress : byte) : byte;
Description	The function reads byte from Port Expander's PortB.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page
Returns	Byte read.
Requires	Port Expander must be initialized. See Expander_Init. Port Expander's PortB should be configured as input. See Expander_Set_DirectionPortB and Expander_Set_DirectionPortAB routines.
Example	// Read a byte from Port Expander's PORTB var read_data : byte; ... Expander_Set_DirectionPortB(0,$FF); // set expander's portb to be input ... read_data := Expander_Read_PortB(0);
Notes	None.

Expander_Read_PortAB

Prototype	function Expander_Read_PortAB(ModuleAddress : byte) : word;
Description	The function reads word from Port Expander's ports. PortA readings are in the higher byte of the result. PortB readings are in the lower byte of the result.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page
Returns	Word read.
Requires	Port Expander must be initialized. See Expander_Init. Port Expander's PortA and PortB should be configured as inputs. See Expander_Set_DirectionPortA, Expander_Set_DirectionPortB and Expander_Set_DirectionPortAB routines.
Example	// Read a byte from Port Expander's PORTA and PORTB var read_data : word; ... Expander_Set_DirectionPortAB(0,$FFFF); // set expander's porta and portb to be input ... read_data := Expander_Read_PortAB(0);
Notes	None.

Expander_Write_PortA

Prototype	procedure Expander_Write_PortA(ModuleAddress, Data : byte);
Description	The function writes byte to Port Expander's PortA.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `Data:` data to be written
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init. Port Expander's PortA should be configured as output. See Expander_Set_DirectionPortA and Expander_Set_DirectionPortAB routines.
Example	// Write a byte to Port Expander's PORTA ... Expander_Set_DirectionPortA(0,$00); // set expander's porta to be output ... Expander_Write_PortA(0, $AA);
Notes	None.

Expander_Write_PortB

Prototype	procedure Expander_Write_PortB(ModuleAddress, Data : byte);
Description	The function writes byte to Port Expander's PortB.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `Data:` data to be written
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init. Port Expander's PortB should be configured as output. See Expander_Set_DirectionPortB and Expander_Set_DirectionPortAB routines.
Example	// Write a byte to Port Expander's PORTB ... Expander_Set_DirectionPortB(0,$00); // set expander's portb to be output ... Expander_Write_PortB(0,$55);
Notes	None.

Expander_Write_PortAB

Prototype	procedure Expander_Write_PortAB(ModuleAddress : byte; Data : word);
Description	The function writes word to Port Expander's ports.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `Data:` data to be written. Data to be written to PortA are passed in `Data`'s higher byte. Data to be written to PortB are passed in `Data`'s lower byte
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init. Port Expander's PortA and PortB should be configured as outputs. See Expander_Set_DirectionPortA, Expander_Set_DirectionPortB and Expander_Set_DirectionPortAB routines.
Example	// Write a byte to Port Expander's PORTA and PORTB ... Expander_Set_DirectionPortAB(0, $0000); // set expander's porta and portb to be output ... Expander_Write_PortAB(0, $AA55);
Notes	None.

Expander_SetBit_PortA

Prototype	procedure Expander_SetBit_PortA(ModuleAddress : byte; BitMask : byte);
Description	The function sets bits designated by the `BitMask` parameter to Port Expander's PortA.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init. Port Expander's PortA should be configured as output. See Expander_Set_DirectionPortA and Expander_Set_DirectionPortAB routines.
Example	// Sets lower nibble of the PortA ... Expander_Set_DirectionPortA(0, $0000); // set expander's PortA to be output ... Expander_SetBit_PortA(0, 0x0F);
Notes	None.

Expander_ClrBit_PortA

Prototype	procedure Expander_ClrBit_PortA(ModuleAddress : byte; BitMask : byte);
Description	The function clears bits designated by the `BitMask` parameter in Port Expander's PortA.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init. Port Expander's PortA should be configured as output. See Expander_Set_DirectionPortA and Expander_Set_DirectionPortAB routines.
Example	// Clears lower nibble of the PortA ... Expander_Set_DirectionPortA(0, $0000); // set expander's PortA to be output ... Expander_ClrBit_PortA(0, 0x0F);
Notes	None.

Expander_ToggleBit_PortA

Prototype	procedure Expander_ToggleBit_PortA(ModuleAddress : byte; BitMask : byte);
Description	The function toggles bits designated by the `BitMask` parameter in Port Expander's PortA.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init. Port Expander's PortA should be configured as output. See Expander_Set_DirectionPortA and Expander_Set_DirectionPortAB routines.
Example	// Toggles lower nibble of the PortA ... Expander_Set_DirectionPortA(0, $0000); // set expander's PortA to be output ... Expander_ToggleBit_PortA(0, 0x0F);
Notes	None.

Expander_SetBit_PortB

Prototype	procedure Expander_SetBit_PortB(ModuleAddress : byte; BitMask : byte);
Description	The function sets bits designated by the `BitMask` parameter to Port Expander's PortB.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init. Port Expander's PortB should be configured as output. See Expander_Set_DirectionPortB and Expander_Set_DirectionPortAB routines.
Example	// Sets lower nibble of the PortB ... Expander_Set_DirectionPortB(0, $0000); // set expander's PortB to be output ... Expander_SetBit_PortB(0, 0x0F);
Notes	None.

Expander_ClrBit_PortB

Prototype	procedure Expander_ClrBit_PortB(ModuleAddress : byte; BitMask : byte);
Description	The function clears bits designated by the `BitMask` parameter in Port Expander's PortB.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init. Port Expander's PortB should be configured as output. See Expander_Set_DirectionPortB and Expander_Set_DirectionPortAB routines.
Example	// Clears lower nibble of the PortB ... Expander_Set_DirectionPortB(0, $0000); // set expander's PortB to be output ... Expander_ClrBit_PortB(0, 0x0F);
Notes	None.

Expander_ToggleBit_PortB

Prototype	procedure Expander_ToggleBit_PortB(ModuleAddress : byte; BitMask : byte);
Description	The function toggles bits designated by the `BitMask` parameter in Port Expander's PortB.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init. Port Expander's PortB should be configured as output. See Expander_Set_DirectionPortB and Expander_Set_DirectionPortAB routines.
Example	// Toggles lower nibble of the PortB ... Expander_Set_DirectionPortB(0, $0000); // set expander's PortB to be output ... Expander_ToggleBit_PortB(0, 0x0F);
Notes	None.

Expander_Set_DirectionPortA

Prototype	procedure Expander_Set_DirectionPortA(ModuleAddress, Data : byte);
Description	The function sets Port Expander's PortA direction.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `Data:` data to be written to the PortA direction register. Each bit corresponds to the appropriate pin of the PortA register. Set bit designates corresponding pin as input. Cleared bit designates corresponding pin as output.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Set Port Expander's PORTA to be output Expander_Set_DirectionPortA(0,$00);
Notes	None.

Expander_Set_DirectionPortB

Prototype	procedure Expander_Set_DirectionPortB(ModuleAddress, Data : byte);
Description	The function sets Port Expander's PortB direction.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `Data:` data to be written to the PortB direction register. Each bit corresponds to the appropriate pin of the PortB register. Set bit designates corresponding pin as input. Cleared bit designates corresponding pin as output.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Set Port Expander's PORTB to be input Expander_Set_DirectionPortB(0,$FF);
Notes	None.

Expander_Set_DirectionPortAB

Prototype	procedure Expander_Set_DirectionPortAB(ModuleAddress, Direction : word);
Description	The function sets Port Expander's PortA and PortB direction.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `Direction:` data to be written to direction registers. Data to be written to the PortA direction register are passed in `Direction`'s higher byte. Data to be written to the PortB direction register are passed in `Direction`'s lower byte. Each bit corresponds to the appropriate pin of the PortA/PortB register. Set bit designates corresponding pin as input. Cleared bit designates corresponding pin as output.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Set Port Expander's PORTA to be output and PORTB to be input Expander_Set_DirectionPortAB(0,$00FF);
Notes	None.

Expander_Set_InputDirPortA

Prototype	procedure Expander_Set_InputDirPortA(ModuleAddress, BitMask : byte);
Description	The function sets the desired Port Expander's PortA pins as input according to the `BitMask` parameter.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Set Port Expander's PORTA lower four pins as input : Expander_Set_InputDirPortA(0, 0x0F);
Notes	None.

Expander_Set_OutputDirPortA

Prototype	procedure Expander_Set_OutputDirPortA(ModuleAddress, BitMask : byte);
Description	The function sets the desired Port Expander's PortB pins as input according to the `BitMask` parameter.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Set Port Expander's PORTA lower four pins as output : Expander_Set_OutputDirPortA(0, 0x0F);
Notes	None.

Expander_Set_InputDirPortB

Prototype	procedure Expander_Set_InputDirPortB(ModuleAddress, BitMask : byte);
Description	The function sets the desired Port Expander's PortB pins as input according to the `BitMask` parameter.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Set Port Expander's PORTB lower four pins as input : Expander_Set_InputDirPortB(0, 0x0F);
Notes	None.

Expander_Set_OutputDirPortB

Prototype	procedure Expander_Set_OutputDirPortB(ModuleAddress, BitMask : byte);
Description	The function sets the desired Port Expander's PortB pins as input according to the `BitMask` parameter.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Set Port Expander's PORTB lower four pins as output : Expander_Set_OutputDirPortB(0, 0x0F);
Notes	None.

Expander_Set_PullUpsPortA

Prototype	procedure Expander_Set_PullUpsPortA(ModuleAddress, Data : byte);
Description	The function sets Port Expander's PortA pull up/down resistors.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `Data:` data for choosing pull up/down resistors configuration. Each bit corresponds to the appropriate pin of the PortA register. Set bit enables pull-up for corresponding pin.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Set Port Expander's PORTA pull-up resistors Expander_Set_PullUpsPortA(0, $FF);
Notes	None.

Expander_Set_PullUpsPortB

Prototype	procedure Expander_Set_PullUpsPortB(ModuleAddress, Data : byte);
Description	The function sets Port Expander's PortB pull up/down resistors.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `Data:` data for choosing pull up/down resistors configuration. Each bit corresponds to the appropriate pin of the PortB register. Set bit enables pull-up for corresponding pin.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Set Port Expander's PORTB pull-up resistors Expander_Set_PullUpsPortB(0, 0xFF);
Notes	None.

Expander_Set_PullUpsPortAB

Prototype	procedure Expander_Set_PullUpsPortAB(ModuleAddress : byte; PullUps : word);
Description	The function sets Port Expander's PortA and PortB pull up/down resistors.
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `PullUps:` data for choosing pull up/down resistors configuration. PortA pull up/down resistors configuration is passed in `PullUps`'s higher byte. PortB pull up/down resistors configuration is passed in `PullUps`'s lower byte. Each bit corresponds to the appropriate pin of the PortA/PortB register. Set bit enables pull-up for corresponding pin.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Set Port Expander's PORTA and PORTB pull-up resistors Expander_Set_PullUpsPortAB(0, $FFFF);
Notes	None.

Expander_SetBits

Prototype	procedure Expander_SetBits(ModuleAddress : byte; RegAddress : byte; BitMask : byte);
Description	The function sets bits designated by the `BitMask` parameter to Port Expander's internal register (`RegAddress` parameter).
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `RegAddress:` Port Expander's internal register address `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Sets lower nibble at the register located on the address 1 of the Port Expander Expander_SetBits(0, 1, 0x0F);
Notes	None.

Expander_ClrBits

Prototype	procedure Expander_ClrBits(ModuleAddress : byte; RegAddress : byte; BitMask : byte);
Description	The function clears bits designated by the `BitMask` parameter in the Port Expander's internal register (`RegAddress` parameter).
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `RegAddress:` Port Expander's internal register address `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Clears lower nibble in the register located on the address 1 of the Port Expander Expander_ClrBits(0, 1, 0x0F);
Notes	None.

Expander_ToggleBits

Prototype	procedure Expander_ToggleBits(ModuleAddress : byte; RegAddress : byte; BitMask : byte);
Description	The function toggles bits designated by the `BitMask` parameter in the Port Expander's internal register (`RegAddress` parameter).
Parameters	`ModuleAddress:` Port Expander hardware address, see schematic at the bottom of this page `RegAddress:` Port Expander's internal register address `BitMask:` appropriate bitmask.
Returns	Nothing.
Requires	Port Expander must be initialized. See Expander_Init.
Example	// Toggles lower nibble in the register located on the address 1 of the Port Expander Expander_ToggleBits(0, 1, 0x0F);
Notes	None.

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