Difference between revisions of "Unit MCP230XX"

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'''Microchip MCP230XX I/O expander Driver unit'''
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'''Microchip MCP230XX I/O Expander Driver unit'''
  
 
The Microchip MCP23008 and MCP23017 are 8 or 16 bit I/O expanders that provide GPIO pin control functions over an I2C connection.
 
The Microchip MCP23008 and MCP23017 are 8 or 16 bit I/O expanders that provide GPIO pin control functions over an I2C connection.

Latest revision as of 05:44, 31 August 2021

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Description

Microchip MCP230XX I/O Expander Driver unit

The Microchip MCP23008 and MCP23017 are 8 or 16 bit I/O expanders that provide GPIO pin control functions over an I2C connection.

The device can be represented in Ultibo as a standard GPIO device which is accessible via the GPIO unit functions. Because the MCP230XX is a chip that can be used and configured in multiple different scenarios this unit does not autocreate a GPIO device, instead you need to call the function MCP23008GPIOCreate or MCP23017GPIOCreate and pass an I2C device and address. The functions will create and return a GPIO device with the appropriate number of pins and other information for the specified chip, the returned devices will have been registered with the GPIO device unit and started ready for use.

Both devices also come in an SPI interface version, these are not currently supported by this unit.

Note: This unit does not currently implement the interrupt capabilities of the MCP230XX chips however it could be expanded to allow the interrupt pin to be connected to a GPIO pin on the SoC and use a trigger event from that to enable GPIOInputWait/GPIOInputEvent functions for the MCP230XX chips.

Constants


MCP230XX specific constants MCP23008_*
MCP23008_GPIO_DESCRIPTION = 'Microchip MCP23008 8-bit I/O Expander'; Description of MCP23008 device
MCP23017_GPIO_DESCRIPTION = 'Microchip MCP23016 16-bit I/O Expander'; Description of MCP23017 device
 
MCP23008_GPIO_MIN_PIN = GPIO_PIN_0;  
MCP23008_GPIO_MAX_PIN = GPIO_PIN_7;  
MCP23008_GPIO_PIN_COUNT = 8;  
 
MCP23017_GPIO_MIN_PIN = GPIO_PIN_0;  
MCP23017_GPIO_MAX_PIN = GPIO_PIN_15;  
MCP23017_GPIO_PIN_COUNT = 16;  
 
MCP230XX_GPIO_MAX_LEVEL = GPIO_LEVEL_HIGH;  
 
MCP230XX_GPIO_MAX_PULL = GPIO_PULL_UP;  
 
MCP230XX_GPIO_MIN_FUNCTION = GPIO_FUNCTION_IN;  
MCP230XX_GPIO_MAX_FUNCTION = GPIO_FUNCTION_OUT;  


MCP230XX chip MCP230XX_CHIP_*
MCP230XX_CHIP_MCP23008 = 0;  
MCP230XX_CHIP_MCP23017 = 1;  


MCP230XX I2C MCP230XX_I2C_*
MCP230XX_I2C_RATE = 400000; Default I2C clock rate (Device supports 100KHz, 400KHz and 1.7MHz)
 
MCP23008_I2C_SIZE = 1; Number of bytes to read/write all pin values for any register
MCP23017_I2C_SIZE = 2; Number of bytes to read/write all pin values for any register
 
MCP230XX_I2C_MAX_SIZE = 2; Maximum number of bytes to read/write all pin values for any register
 
MCP23008_I2C_MAX_REG = $0A; Maximum register address for the I2C interface
MCP23017_I2C_MAX_REG = $1A; Maximum register address for the I2C interface (Only 21 (0x15) registers exists, mappings differ between modes)


Type definitions


MCP230XX GPIO types

PMCP230XXGPIO = ^TMCP230XXGPIO;

TMCP230XXGPIO = record

GPIO Properties
GPIO:TGPIODevice;  
MCP230XX Properties
I2C:PI2CDevice; The I2C device this GPIO is connected to
Address:Word; The I2C address of the device
Chip:LongWord; The chip type (eg MCP230XX_CHIP_MCP23008)
Size:LongWord; Size of an I2C read/write for the device
GPIOReg:Byte; GPIO port register for the device
GPPUReg:Byte; GPPU pull up resistor register for the device
IODIRReg:Byte; IODIR I/O direction register for the device
GPIOValues:array[0..MCP230XX_I2C_MAX_SIZE - 1] of Byte; Buffer for GPIO port values (Output only)
GPPUValues:array[0..MCP230XX_I2C_MAX_SIZE - 1] of Byte; Buffer for GPPU pull up values
IODIRValues:array[0..MCP230XX_I2C_MAX_SIZE - 1] of Byte; Buffer for IODIR I/O direction values


Public variables

None defined

Function declarations


MCP230XX functions 

function MCP23008GPIOCreate(I2C:PI2CDevice; Address:Word):PGPIODevice;
Description: Create, register and start a new MCP23008 GPIO device connected to the specified I2C device
I2C The I2C device this MCP23008 is connected to
Address The I2C address for this MCP23008
Return Pointer to the new GPIO device or nil on failure 


function MCP23017GPIOCreate(I2C:PI2CDevice; Address:Word):PGPIODevice;
Description: Create, register and start a new MCP23017 GPIO device connected to the specified I2C device
I2C The I2C device this MCP23017 is connected to
Address The I2C address for this MCP23017
Return Pointer to the new GPIO device or nil on failure 


function MCP230XXGPIODestroy(GPIO:PGPIODevice):LongWord;
Description: Stop, deregister and destroy an MCP230XX GPIO device created by this driver
GPIO The GPIO device to destroy
Return ERROR_SUCCESS if completed or another error code on failure


MCP230XX GPIO functions 

function MCP230XXGPIOStart(GPIO:PGPIODevice):LongWord;
Description: Implementation of GPIODeviceStart API for MCP230XX
Note Not intended to be called directly by applications, use GPIODeviceStart instead. 


function MCP230XXGPIOStop(GPIO:PGPIODevice):LongWord;
Description: Implementation of GPIODeviceStop API for MCP230XX
Note Not intended to be called directly by applications, use GPIODeviceStop instead. 


function MCP230XXGPIORead(GPIO:PGPIODevice; Reg:LongWord):LongWord;
Description: Implementation of GPIODeviceRead API for MCP230XX
Note Not intended to be called directly by applications, use GPIODeviceRead instead.

Will read only a single register byte 


procedure MCP230XXGPIOWrite(GPIO:PGPIODevice; Reg,Value:LongWord);
Description: Implementation of GPIODeviceWrite API for MCP230XX
Note Not intended to be called directly by applications, use GPIODeviceWrite instead.

Will write only a single register byte 


function MCP230XXGPIOInputGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;
Description: Implementation of GPIODeviceInputGet API for MCP230XX
Note Not intended to be called directly by applications, use GPIODeviceInputGet instead. 


function MCP230XXGPIOOutputSet(GPIO:PGPIODevice; Pin,Level:LongWord):LongWord;
Description: Implementation of GPIODeviceOutputSet API for MCP230XX
Note Not intended to be called directly by applications, use GPIODeviceOutputSet instead. 


function MCP230XXGPIOPullGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;
Description: Implementation of GPIODevicePullGet API for MCP230XX
Note Not intended to be called directly by applications, use GPIODevicePullGet instead. 


function MCP230XXGPIOPullSelect(GPIO:PGPIODevice; Pin,Mode:LongWord):LongWord;
Description: Implementation of GPIODevicePullSelect API for MCP230XX
Note Not intended to be called directly by applications, use GPIODevicePullSelect instead. 


function MCP230XXGPIOFunctionGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;
Description: Implementation of GPIODeviceFunctionGet API for MCP230XX
Note Not intended to be called directly by applications, use GPIODeviceFunctionGet instead. 


function MCP230XXGPIOFunctionSelect(GPIO:PGPIODevice; Pin,Mode:LongWord):LongWord;
Description: Implementation of GPIODeviceFunctionSelect API for MCP230XX
Note Not intended to be called directly by applications, use GPIODeviceFunctionSelect instead.


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