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Class PinRef

ClassList > PinRef

Hardware pin abstraction used by all OpenSkyhawk input and output classes.More...

  • #include <PinRef.h>

Public Attributes

Type Name
ADS1115 * adc
struct PinRef ads
ADS1115 source.
uint8_t bit
uint8_t channel
MCP23017 * chip
struct PinRef mcp
MCP23017 source.
uint8_t pin
GPIO pin number.
uint8_t port

Public Functions

Type Name
PinRef (uint8_t pin)
Direct STM32 GPIO pin.
PinRef (MCP23017 & chip, uint8_t port, uint8_t bit)
MCP23017 expander GPIO.
PinRef (ADS1115 & adc, uint8_t channel)
ADS1115 ADC channel.
constexpr PinRef ()
No-connect sentinel — represents a position with no physical pin.
void configureAsInput ()
Configure this pin as a digital input.
void configureAsOutput ()
Configure this pin as a digital output.
uint8_t gpioPin () const
Return the raw Arduino pin number for GPIO PinRefs.
bool isGpio () const
Returns true if this PinRef wraps a direct STM32 GPIO pin.
bool isNC () const
Returns true if this is the NC (no-connect) sentinel.
bool read () const
Digital read.
uint16_t readAnalog () const
Analog read, normalised to 16-bit (0–65535).
bool readLive () const
Live digital read — bypasses any cache.
void write (bool value)
Digital write.
void writeAnalog (uint16_t val)
Analog write (PWM). GPIO only.
void writeDeferred (bool value)
Like write() , but MCP writes only update the cache (no I2C) — the caller then invokesPanelGroup::flushExpanderWrites() to push each port in one writePort().

Detailed Description

Provides read, write, readAnalog, and writeAnalog behind a uniform interface regardless of whether the backing pin is a direct STM32 GPIO, an MCP23017 expander bit, or an ADS1115 ADC channel. Size: ~12 bytes (1-byte type tag + largest union member).

Public Attributes Documentation

variable adc

ADS1115* PinRef::adc;

variable ads

ADS1115 source.

struct PinRef PinRef::ads;

variable bit

uint8_t PinRef::bit;

variable channel

uint8_t PinRef::channel;

variable chip

MCP23017* PinRef::chip;

variable mcp

MCP23017 source. 

struct PinRef PinRef::mcp;

variable pin

GPIO pin number. 

uint8_t PinRef::pin;

variable port

uint8_t PinRef::port;

Public Functions Documentation

function PinRef [1/4]

Direct STM32 GPIO pin. 

explicit PinRef::PinRef (
    uint8_t pin
)

Parameters:

  • pin Arduino pin number (e.g. PA0, PB5).

function PinRef [2/4]

MCP23017 expander GPIO. 

PinRef::PinRef (
    MCP23017 & chip,
    uint8_t port,
    uint8_t bit
)

Parameters:

  • chip Reference to the registered MCP23017 instance.
  • port PORT_A (0) or PORT_B (1).
  • bit Bit within the port, 0–7.

function PinRef [3/4]

ADS1115 ADC channel.

PinRef::PinRef (
    ADS1115 & adc,
    uint8_t channel
)

Parameters:

  • adc Reference to the ADS1115 instance.
  • channel Channel number, 0–3.

function PinRef [4/4]

No-connect sentinel — represents a position with no physical pin. 

inline constexpr PinRef::PinRef ()

All reads return false / 0. All writes are no-ops. Equivalent to PIN_NC. Provided for use in array initialisers.

Note:

constexpr so PIN_NC — and any default-constructed NC PinRef — is constant-initialized. This makes it safe to place in a global wiring-map array without the static-initialization-order hazard a dynamically-initialized global would have.

function configureAsInput

Configure this pin as a digital input. 

void PinRef::configureAsInput ()

GPIO: calls pinMode(pin, INPUT). Bias is provided by board wiring. MCP23017: sets IODIR bit to 1 (input) and GPPU bit to 0 (pull-up disabled) for this pin only via PanelGroup's expander management path. ADS1115: no-op — always an analog input. NC: no-op.

Note:

Must be called after chip.begin() — i.e. from an InputBase::configure() override called by PanelGroup::setup(), not from a constructor.

function configureAsOutput

Configure this pin as a digital output. 

void PinRef::configureAsOutput ()

GPIO: calls pinMode(pin, OUTPUT). MCP23017: sets IODIR bit to 0 (output) and GPPU bit to 0 (pull-up disabled) for this pin only via PanelGroup's expander management path. ADS1115: no-op; debug assertion fires if PINREF_DEBUG is defined. NC: no-op.

Note:

Must be called after chip.begin() — i.e. from an OutputBase::configure() override called by PanelGroup::setup(), not from a constructor.

function gpioPin

Return the raw Arduino pin number for GPIO PinRefs. 

uint8_t PinRef::gpioPin () const

Used by output classes that must call APIs requiring a raw pin number, such as Servo::attach().

Returns:

Arduino pin number (e.g. PA0, PB9), or 0 for non-GPIO PinRefs.

Note:

Debug builds log if called on non-GPIO PinRefs.

function isGpio

Returns true if this PinRef wraps a direct STM32 GPIO pin.

bool PinRef::isGpio () const

Used by direct-only output classes (AnalogOutput, ServoOutput) to reject MCP23017, ADS1115, and NC pins at construction time.

function isNC

Returns true if this is the NC (no-connect) sentinel. 

bool PinRef::isNC () const

function read

Digital read. 

bool PinRef::read () const

GPIO: digitalRead(pin) — true when the pin is HIGH. MCP23017: cached bit from PanelGroup's last INTCAP or port read. No I2C. ADS1115: true if readAnalog() > 32767 (half-scale threshold). NC: always false.

Returns:

true = HIGH, false = LOW.

function readAnalog

Analog read, normalised to 16-bit (0–65535). 

uint16_t PinRef::readAnalog () const

GPIO: analogRead(pin) × 16 → 0–65520 (12-bit ADC scaled to 16-bit). ADS1115: readADC_SingleEnded(channel) × 2 → 0–65534 (15-bit single-ended scaled). MCP23017: always 0; debug assertion fires if PINREF_DEBUG is defined. NC: always 0.

Returns:

Normalised 16-bit ADC value.

Note:

Do not call from an ISR on ADS1115 pins — blocks ~8 ms per conversion.

function readLive

Live digital read — bypasses any cache. 

bool PinRef::readLive () const

GPIO: digitalRead(pin) (already live). MCP23017: a fresh readPort() over I2C, also refreshing PanelGroup's cache. ADS1115: live readAnalog() > half-scale. NC: false.

Returns:

true = HIGH, false = LOW.

Note:

For time-critical reads before PanelGroup::loop() refreshes the cache — e.g. blocking homing on an MCP-backed sensor. Costs one I2C transaction per call on MCP pins.

function write

Digital write. 

void PinRef::write (
    bool value
)

GPIO: digitalWrite(pin, value ? HIGH : LOW). MCP23017: sets the output bit via PanelGroup's expander write path and cache. ADS1115: no-op; debug assertion fires if PINREF_DEBUG is defined. NC: no-op.

Parameters:

  • value true = HIGH, false = LOW.

function writeAnalog

Analog write (PWM). GPIO only. 

void PinRef::writeAnalog (
    uint16_t val
)

GPIO: analogWrite(pin, val >> 8) — maps 16-bit value to 8-bit duty cycle. MCP23017: no-op; debug assertion fires if PINREF_DEBUG is defined. ADS1115: no-op; debug assertion fires if PINREF_DEBUG is defined. NC: no-op.

Parameters:

  • val 16-bit value (0–65535); upper 8 bits used as PWM duty cycle.

Note:

Pin must be a PWM-capable STM32 GPIO. No runtime check is performed.

function writeDeferred

Like write() , but MCP writes only update the cache (no I2C) — the caller then invokesPanelGroup::flushExpanderWrites() to push each port in one writePort().

void PinRef::writeDeferred (
    bool value
)

GPIO writes stay immediate (already cheap). Lets a multi-pin output batch its expander writes: one I2C transaction per port instead of one read-modify-write per pin.

Parameters:

  • value true = HIGH, false = LOW.

The documentation for this class was generated from the following file Firmware/Libraries/PanelGroup/PinRef.h