MCP23017 Library for STM32 MCU's

Implementation Description:

The following implementation contains the MCP23017 class, which is used to operate the MCP23017 I/O expander via the I2C bus. The class allows configuration, control, and reading of the states of the pins and ports of the expander.

Functionality Description:

1. Constructor and Destructor:

   • The constructor initializes the device address and the handle to the I2C bus.
   • The default destructor does not perform any operations.

2. Initialization:

   • The init method configures the IOCON, GPPU_A, and GPPU_B registers, sets the port mode to output, and resets the states of the GPIO_A and GPIO_B ports. This prepares the expander for operation by setting the appropriate initial parameters.

3. Port Configuration:

   • The portMode method sets the mode of operation for the ports (direction, pull-up, inversion).

4. Pin Configuration:

   • The pinMode method configures the mode of operation for a specific pin (input, output, pull-up, inversion).

5. Pin Operations:

   • The writePin method sets the state of a specific pin to HIGH or LOW.
   • The readPin method reads the state of a specific pin (HIGH or LOW).

6. Port Operations:

   • The writePort method sets the value of an entire port (8 pins).
   • The writeWholeIO method sets the values of all pins (16 pins).
   • The readPort method reads the value of an entire port.
   • The readWholeIO method reads the values of all pins.

7. Register Operations:

   • The writeRegister and readRegister methods write to and read the values of the expander's registers via the I2C bus.

8. Interrupt Configuration:

   • The interruptMode method sets the interrupt mode (AND/OR).
   • The interrupt method configures the interrupt triggering method (state change, falling edge, rising edge).
   • The interruptedBy, disableInterrupt, and clearInterrupts methods handle checking, disabling, and clearing interrupts.

Function Descriptions:

1. Constructor:

   • Purpose: Initializes the MCP23017 object with the device address and I2C bus handle.
   • Parameters:
     • uint8_t address: The I2C address of the MCP23017 device.
     • I2C_HandleTypeDef &bus: The I2C bus handle for communication.

2. Destructor:

   • Purpose: Cleans up the MCP23017 object. No specific operations are performed.

3. init():

   • Purpose: Initializes the MCP23017 device by configuring control registers and setting port modes and states.
   • Actions:
     • Configures IOCON register.
     • Enables pull-up resistors on ports A and B.
     • Sets ports A and B to output mode.
     • Resets the states of ports A and B.

4. portMode(MCP23017Port port, uint8_t directions, uint8_t pullups, uint8_t inverted):

   • Purpose: Sets the mode of operation for a specified port.
   • Parameters:
     • MCP23017Port port: The port to configure (PORT_A or PORT_B).
     • uint8_t directions: The direction of the pins (input or output).
     • uint8_t pullups: The pull-up resistor configuration.
     • uint8_t inverted: The polarity inversion configuration.

5. pinMode(uint8_t pin, uint8_t mode, bool inverted):

   • Purpose: Configures the mode of operation for a specific pin.
   • Parameters:
     • uint8_t pin: The pin number to configure.
     • uint8_t mode: The mode of the pin (input, output, input pull-up).
     • bool inverted: Indicates whether the pin state should be inverted.

6. writePin(uint8_t pin, uint8_t state):

   • Purpose: Sets the state of a specific pin to HIGH or LOW.
   • Parameters:
     • uint8_t pin: The pin number to write to.
     • uint8_t state: The state to set (HIGH or LOW).

7. readPin(uint8_t pin):

   • Purpose: Reads the state of a specific pin (HIGH or LOW).
   • Parameters:
     • uint8_t pin: The pin number to read from.
   • Returns: The state of the pin (HIGH or LOW).

8. writePort(MCP23017Port port, uint8_t value):

   • Purpose: Sets the value of an entire port.
   • Parameters:
     • MCP23017Port port: The port to write to (PORT_A or PORT_B).
     • uint8_t value: The value to set for the port.

9. writeWholeIO(uint16_t value):

   • Purpose: Sets the values of all pins (16 pins).
   • Parameters:
     • uint16_t value: The value to set for all pins.

10. readPort(MCP23017Port port):

    • Purpose: Reads the value of an entire port.
    • Parameters:
      • MCP23017Port port: The port to read from (PORT_A or PORT_B).
    • Returns: The value of the port.

11. readWholeIO():

    • Purpose: Reads the values of all pins.
    • Returns: The values of all pins as a 16-bit integer.

12. writeRegister(MCP23017Register reg, uint8_t value):

    • Purpose: Writes a value to a specified register.
    • Parameters:
      • MCP23017Register reg: The register to write to.
      • uint8_t value: The value to write to the register.

13. readRegister(MCP23017Register reg):

    • Purpose: Reads the value of a specified register.
    • Parameters:
      • MCP23017Register reg: The register to read from.
    • Returns: The value of the register.

14. interruptMode(MCP23017InterruptMode intMode):

    • Purpose: Sets the interrupt mode (AND/OR).
    • Parameters:
      • MCP23017InterruptMode intMode: The interrupt mode to set.

15. interrupt(MCP23017Port port, uint8_t mode):

    • Purpose: Configures the interrupt triggering method.
    • Parameters:
      • MCP23017Port port: The port to configure (PORT_A or PORT_B).
      • uint8_t mode: The interrupt triggering method (state change, falling edge, rising edge).

16. interruptedBy(uint8_t &portA, uint8_t &portB):

    • Purpose: Checks which pins triggered an interrupt.
    • Parameters:
      • uint8_t &portA: Reference to store the interrupt status of port A.
      • uint8_t &portB: Reference to store the interrupt status of port B.

17. disableInterrupt(MCP23017Port port):

    • Purpose: Disables interrupts on a specified port.
    • Parameters:
      • MCP23017Port port: The port to disable interrupts on (PORT_A or PORT_B).

18. clearInterrupts():

    • Purpose: Clears all interrupts.

19. clearInterrupts(uint8_t &portA, uint8_t &portB):

    • Purpose: Clears interrupts and reads the captured state of the pins.
    • Parameters:
      • uint8_t &portA: Reference to store the captured state of port A.
      • uint8_t &portB: Reference to store the captured state of port B.

Flow diagram:

Class diagram: