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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
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MCP230XX specific constants MCP23008_*
MCP23008_GPIO_DESCRIPTION = 'Microchip MCP23008 8-bit I/O Expander';
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Description of MCP23008 device
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MCP23017_GPIO_DESCRIPTION = 'Microchip MCP23016 16-bit I/O Expander';
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Description of MCP23017 device
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MCP23008_GPIO_MIN_PIN = GPIO_PIN_0;
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MCP23008_GPIO_MAX_PIN = GPIO_PIN_7;
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MCP23008_GPIO_PIN_COUNT = 8;
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MCP23017_GPIO_MIN_PIN = GPIO_PIN_0;
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MCP23017_GPIO_MAX_PIN = GPIO_PIN_15;
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MCP23017_GPIO_PIN_COUNT = 16;
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MCP230XX_GPIO_MAX_LEVEL = GPIO_LEVEL_HIGH;
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MCP230XX_GPIO_MAX_PULL = GPIO_PULL_UP;
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MCP230XX_GPIO_MIN_FUNCTION = GPIO_FUNCTION_IN;
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MCP230XX_GPIO_MAX_FUNCTION = GPIO_FUNCTION_OUT;
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MCP230XX chip MCP230XX_CHIP_*
MCP230XX_CHIP_MCP23008 = 0;
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MCP230XX_CHIP_MCP23017 = 1;
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MCP230XX I2C MCP230XX_I2C_*
MCP230XX_I2C_RATE = 400000;
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Default I2C clock rate (Device supports 100KHz, 400KHz and 1.7MHz)
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MCP23008_I2C_SIZE = 1;
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Number of bytes to read/write all pin values for any register
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MCP23017_I2C_SIZE = 2;
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Number of bytes to read/write all pin values for any register
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MCP230XX_I2C_MAX_SIZE = 2;
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Maximum number of bytes to read/write all pin values for any register
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MCP23008_I2C_MAX_REG = $0A;
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Maximum register address for the I2C interface
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MCP23017_I2C_MAX_REG = $1A;
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Maximum register address for the I2C interface (Only 21 (0x15) registers exists, mappings differ between modes)
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Type definitions
MCP230XX GPIO types
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PMCP230XXGPIO = ^TMCP230XXGPIO;
TMCP230XXGPIO = record
| GPIO Properties
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GPIO:TGPIODevice;
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| MCP230XX Properties
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I2C:PI2CDevice;
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The I2C device this GPIO is connected to
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Address:Word;
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The I2C address of the device
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Chip:LongWord;
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The chip type (eg MCP230XX_CHIP_MCP23008)
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Size:LongWord;
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Size of an I2C read/write for the device
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GPIOReg:Byte;
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GPIO port register for the device
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GPPUReg:Byte;
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GPPU pull up resistor register for the device
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IODIRReg:Byte;
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IODIR I/O direction register for the device
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GPIOValues:array[0..MCP230XX_I2C_MAX_SIZE - 1] of Byte;
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Buffer for GPIO port values (Output only)
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GPPUValues:array[0..MCP230XX_I2C_MAX_SIZE - 1] of Byte;
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Buffer for GPPU pull up values
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IODIRValues:array[0..MCP230XX_I2C_MAX_SIZE - 1] of Byte;
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Buffer for IODIR I/O direction values
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Public variables
None defined
Function declarations
MCP230XX functions
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function MCP23008GPIOCreate(I2C:PI2CDevice; Address:Word):PGPIODevice;
Description: Create, register and start a new MCP23008 GPIO device connected to the specified I2C device
| I2C
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The I2C device this MCP23008 is connected to
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| Address
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The I2C address for this MCP23008
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| Return
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Pointer to the new GPIO device or nil on failure
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function MCP23017GPIOCreate(I2C:PI2CDevice; Address:Word):PGPIODevice;
Description: Create, register and start a new MCP23017 GPIO device connected to the specified I2C device
| I2C
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The I2C device this MCP23017 is connected to
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| Address
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The I2C address for this MCP23017
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| Return
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Pointer to the new GPIO device or nil on failure
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function MCP230XXGPIODestroy(GPIO:PGPIODevice):LongWord;
Description: Stop, deregister and destroy an MCP230XX GPIO device created by this driver
| GPIO
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The GPIO device to destroy
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| Return
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ERROR_SUCCESS if completed or another error code on failure
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MCP230XX GPIO functions
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function MCP230XXGPIOStart(GPIO:PGPIODevice):LongWord;
Description: Implementation of GPIODeviceStart API for MCP230XX
| Note
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Not intended to be called directly by applications, use GPIODeviceStart instead.
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function MCP230XXGPIOStop(GPIO:PGPIODevice):LongWord;
Description: Implementation of GPIODeviceStop API for MCP230XX
| Note
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Not intended to be called directly by applications, use GPIODeviceStop instead.
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function MCP230XXGPIORead(GPIO:PGPIODevice; Reg:LongWord):LongWord;
Description: Implementation of GPIODeviceRead API for MCP230XX
| Note
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Not intended to be called directly by applications, use GPIODeviceRead instead.
Will read only a single register byte
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procedure MCP230XXGPIOWrite(GPIO:PGPIODevice; Reg,Value:LongWord);
Description: Implementation of GPIODeviceWrite API for MCP230XX
| Note
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Not intended to be called directly by applications, use GPIODeviceWrite instead.
Will write only a single register byte
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function MCP230XXGPIOInputGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;
Description: Implementation of GPIODeviceInputGet API for MCP230XX
| Note
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Not intended to be called directly by applications, use GPIODeviceInputGet instead.
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function MCP230XXGPIOOutputSet(GPIO:PGPIODevice; Pin,Level:LongWord):LongWord;
Description: Implementation of GPIODeviceOutputSet API for MCP230XX
| Note
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Not intended to be called directly by applications, use GPIODeviceOutputSet instead.
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function MCP230XXGPIOPullGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;
Description: Implementation of GPIODevicePullGet API for MCP230XX
| Note
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Not intended to be called directly by applications, use GPIODevicePullGet instead.
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function MCP230XXGPIOPullSelect(GPIO:PGPIODevice; Pin,Mode:LongWord):LongWord;
Description: Implementation of GPIODevicePullSelect API for MCP230XX
| Note
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Not intended to be called directly by applications, use GPIODevicePullSelect instead.
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function MCP230XXGPIOFunctionGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;
Description: Implementation of GPIODeviceFunctionGet API for MCP230XX
| Note
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Not intended to be called directly by applications, use GPIODeviceFunctionGet instead.
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function MCP230XXGPIOFunctionSelect(GPIO:PGPIODevice; Pin,Mode:LongWord):LongWord;
Description: Implementation of GPIODeviceFunctionSelect API for MCP230XX
| Note
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Not intended to be called directly by applications, use GPIODeviceFunctionSelect instead.
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