One-stop pin self-test utility with a single dispatcher entry point. More...

#include <PstTestPins.h>

Public Types
enum class	Type : uint8_t { IO , Input , Output , OpenDrain , ADC , I2C_SDA , I2C_SCL , PWM , Button , UART_RX , UART_TX , McpInput , Unknown }
	Declares the intended role of the pin so the dispatcher can run sensible tests. More...

Public Member Functions
	PstTestPins ()
	Default constructor (no configuration needed for ESP32).

bool	testPin (uint8_t pin, Type type, const char *label=nullptr) const
	Run the appropriate self-test(s) for a pin based on its Type. More...

bool	testMcpInput (Adafruit_MCP23017 pMcp, uint8_t mcpPin, const char name) const
	Run an input-only test on a port expander pin. More...

bool	testOpen (uint8_t pin, const char *label=nullptr, bool gentle=false) const
	Run only the "open" heuristic on a pin. More...

bool	testShorted (uint8_t pin, const char *label=nullptr, bool gentle=false) const
	Run only the "shorted" heuristic on a pin. More...

Static Public Member Functions
static void	set_led (uint8_t pin, bool on)
	Convenience: drive an indicator LED with active-LOW polarity. More...

static void	init_led (uint8_t pin)
	Initialize an indicator LED pin (OUTPUT, start OFF). More...

Private Member Functions
bool	_testUartTx (uint8_t pin, const char *label) const
	UART-aware TX test (no loopback/jumpers required). More...

bool	_testOpen (uint8_t pin, const char *name, bool gentle=false) const
	Heuristic "open” check using internal pulls. More...

bool	_testShorted (uint8_t pin, const char *name, bool gentle=false) const
	Detects pins stuck HIGH or LOW using internal pulls. More...

bool	_testDriveRead (uint8_t pin, const char *name) const
	Output toggle/readback sanity check. More...

bool	_testOpenDrain (uint8_t pin, const char *name) const
	Open-drain verification: LOW drive then released HIGH (via pull-up). More...

bool	_testAdc (uint8_t pin, const char *name) const
	ADC sanity check using ESP32 calibrated read (millivolts). More...

bool	_testI2cLineCheck (uint8_t pin, const char name, const char lineName) const
	Preferred I²C line health check (no pulls, then diagnostic “nudge”). More...

Static Private Member Functions
static bool	_isInputOnly (uint8_t pin)
	Returns true if a GPIO is input-only on ESP32 (GPIO 34-39). More...

static bool	_hasInternalPulls (uint8_t pin)
	Returns true if the pin supports internal pull resistors. More...

Detailed Description

One-stop pin self-test utility with a single dispatcher entry point.

GPIO self‑test utility for LCC Fusion cards.

The dispatcher PstTestPins::testPin chooses appropriate checks based on PstTestPins::Type:

IO / Output: shorted check, open check, drive/readback
Input / Button: shorted check, open check
OpenDrain: open-drain specific drive/release behavior
ADC: reads calibrated millivolts and flags stuck-low/high
I2C_SDA / I2C_SCL: verifies bus lines idle HIGH without our pulls; diagnoses missing pull-ups vs. stuck-low
PWM: basic HIGH/LOW toggle sanity
UART_RX / UART_TX: UART-aware prep (gentle open/short on RX, idle HIGH on TX) then delegate to Input/Output paths
Mcp Input / Button: shorted check, open check

PstTestPins performs a suite of simple electrical checks on ESP32 pins (and MCP23017 expander pins) to help builders verify correct wiring and soldering before firmware initialization. Tests include checking for stuck pins, opens, shorts between power rails, basic drive/readback functionality and, for open‑drain and UART pins, appropriate biasing. Results are printed via the global g_serialIO using human‑readable language. Use testPin() to run tests appropriate for a given pin’s intended role (see Type).

Definition at line 62 of file PstTestPins.h.

Member Enumeration Documentation

◆ Type

enum class PstTestPins::Type : uint8_t

strong

Declares the intended role of the pin so the dispatcher can run sensible tests.

Enumerator
IO	General‑purpose pin capable of input and output
Input	Digital input only
Output	Digital output
OpenDrain	Open‑drain output: active LOW when driven, HIGH when released
ADC	Analog input channel
I2C_SDA	I²C data line (SDA); should idle HIGH
I2C_SCL	I²C clock line (SCL); should idle HIGH
PWM	PWM‑capable output; test performs a simple HIGH/LOW toggle
Button	Momentary input such as a push‑button
UART_RX	UART receive pin; DFPlayer TX -> ESP32 RX; uses gentle bias
UART_TX	UART transmit pin; ESP32 TX -> DFPlayer RX; idles HIGH
McpInput	Input on an MCP23017 expander; tested via testMcpInput()
Unknown	Unspecified or unsupported pin type

Definition at line 68 of file PstTestPins.h.

Member Function Documentation

◆ _hasInternalPulls()

static bool PstTestPins::_hasInternalPulls ( uint8_t pin )

inlinestaticprivate

Returns true if the pin supports internal pull resistors.

Parameters

pin	GPIO number.

Note: On ESP32, GPIO 34-39 are input-only and lack internal pulls.

Definition at line 295 of file PstTestPins.h.

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◆ _isInputOnly()

static bool PstTestPins::_isInputOnly ( uint8_t pin )

inlinestaticprivate

Returns true if a GPIO is input-only on ESP32 (GPIO 34-39).

Parameters

pin	GPIO number.

Note: Used to skip drive tests and internal pull "nudges” where unsupported.

Definition at line 285 of file PstTestPins.h.

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◆ _testAdc()

bool PstTestPins::_testAdc	(	uint8_t	pin,
		const char *	name
	)		const

inlineprivate

ADC sanity check using ESP32 calibrated read (millivolts).

Sets 11 dB attenuation (valid up to ~3.3 V), averages several samples, and flags likely shorts: near 0 mV (short to GND) or near 3.3 V (short to 3V3).

Parameters

pin	ADC-capable GPIO (ADC1 recommended).
name	Label printed in logs.

Returns: true if value is in a reasonable range; false if near-0 or near-full-scale.

Definition at line 532 of file PstTestPins.h.

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◆ _testDriveRead()

bool PstTestPins::_testDriveRead	(	uint8_t	pin,
		const char *	name
	)		const

inlineprivate

Output toggle/readback sanity check.

Skips driving input-only pins. For others:

Drive HIGH → expect to read HIGH
Drive LOW → expect to read LOW

Parameters

pin	GPIO under test.
name	Label printed in logs.

Returns: true if both levels read back as expected; false otherwise.

Definition at line 459 of file PstTestPins.h.

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◆ _testI2cLineCheck()

bool PstTestPins::_testI2cLineCheck	(	uint8_t	pin,
		const char *	name,
		const char *	lineName
	)		const

inlineprivate

Preferred I²C line health check (no pulls, then diagnostic “nudge”).

Note: Assumes external 3.3 V pull-ups (≈2.2–10 kΩ) are present and powered on the bus. On a bare bench (no pull-ups / unpowered target), this test will report “missing pull-up” by design.

Procedure: 1) Observe the line as INPUT (no internal pull). A healthy, powered bus idles HIGH. 2) If LOW, briefly enable INPUT_PULLUP:

If it goes HIGH, likely missing/not-powered external pull-up.
If it stays LOW, likely shorted or a device is holding the line.

Parameters

pin	GPIO to check.
name	Label for logs.
lineName	"SDA" or "SCL" (for messages).

Returns: true if line is HIGH at idle without our pulls; false otherwise.

Definition at line 575 of file PstTestPins.h.

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◆ _testOpen()

bool PstTestPins::_testOpen	(	uint8_t	pin,
		const char *	name,
		bool	gentle = `false`
	)		const

inlineprivate

Heuristic "open” check using internal pulls.

When gentle is false (default), performs a full up/down nudge:

INPUT_PULLUP → read
INPUT_PULLDOWN → read A good open net follows both nudges (HIGH with PULLUP, LOW with PULLDOWN).

When gentle is true (UART-safe), avoids PULLDOWN (never weakly drives LOW):

unbiased INPUT → read (idle)
INPUT_PULLUP → read (up)

Skips nudges on input-only pins (no internal pulls).

Parameters

pin	GPIO under test.
name	Label printed in logs.
gentle	If true, avoid INPUT_PULLDOWN and use a UART-safe probe.

Returns: true if behavior matches expectations; false if stuck or odd readings.

Definition at line 319 of file PstTestPins.h.

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◆ _testOpenDrain()

bool PstTestPins::_testOpenDrain	(	uint8_t	pin,
		const char *	name
	)		const

inlineprivate

Open-drain verification: LOW drive then released HIGH (via pull-up).

Procedure:

Actively drive LOW and confirm readback LOW.
Switch to INPUT_PULLUP (release) and confirm readback HIGH.

Parameters

pin	GPIO under test.
name	Label printed in logs.

Returns: true on expected behavior; false if mismatch.

Definition at line 496 of file PstTestPins.h.

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◆ _testShorted()

bool PstTestPins::_testShorted	(	uint8_t	pin,
		const char *	name,
		bool	gentle = `false`
	)		const

inlineprivate

Detects pins stuck HIGH or LOW using internal pulls.

When gentle is false (default), performs a full up/down nudge:

INPUT_PULLUP → read
INPUT_PULLDOWN → read If both reads are LOW → likely shorted LOW. If both HIGH → likely shorted HIGH.

When gentle is true (UART-safe), avoids PULLDOWN; we only test the ability to go HIGH:

unbiased INPUT → read
INPUT_PULLUP → read

Skips nudges on input-only pins (no internal pulls).

Parameters

pin	GPIO under test.
name	Label printed in logs.
gentle	If true, avoid INPUT_PULLDOWN and use a UART-safe probe.

Returns: true if not obviously stuck; false if likely shorted.

Definition at line 397 of file PstTestPins.h.

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◆ _testUartTx()

bool PstTestPins::_testUartTx	(	uint8_t	pin,
		const char *	label
	)		const

inlineprivate

UART-aware TX test (no loopback/jumpers required).

Behavior:

Sets UART idle level HIGH (OUTPUT, HIGH) before testing to avoid sending long LOW pulses into a receiver.
Delegates to the standard Output checks (shorted + drive/readback) for consistent reporting.

Parameters

pin	ESP32 TX GPIO (connected to DFPlayer RX).
label	Label printed in logs.

Returns: true if delegated Output tests pass; false otherwise.

Definition at line 267 of file PstTestPins.h.

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◆ init_led()

static void PstTestPins::init_led ( uint8_t pin )

inlinestatic

Initialize an indicator LED pin (OUTPUT, start OFF).

Parameters

pin LED GPIO.

Definition at line 115 of file PstTestPins.h.

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◆ set_led()

static void PstTestPins::set_led	(	uint8_t	pin,
		bool	on
	)

inlinestatic

Convenience: drive an indicator LED with active-LOW polarity.

Parameters

pin	LED GPIO.
on	True to turn LED on (drives LOW), false to turn off (drives HIGH).

Definition at line 106 of file PstTestPins.h.

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◆ testMcpInput()

bool PstTestPins::testMcpInput	(	Adafruit_MCP23017 *	pMcp,
		uint8_t	mcpPin,
		const char *	name
	)		const

inline

Run an input-only test on a port expander pin.

Configures the specified MCP23017 pin as a pulled‑up input and prints whether it reads LOW (wired to ground) or HIGH (floating). It does not drive the pin or change its OLAT register, so it is safe to call for unconnected inputs. If pMcp is null the function logs a warning and returns false.

Parameters

pMcp	Pointer to a configured Adafruit_MCP23017 instance.
mcpPin	MCP23017 pin number (0–15) to test.
name	Optional label used in log messages; defaults to "MCP_PIN".

Return values

true	The test completed (always informational; does not flag failure).
false	`pMcp` was null and the test did not run.

Definition at line 205 of file PstTestPins.h.

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◆ testOpen()

bool PstTestPins::testOpen	(	uint8_t	pin,
		const char *	label = `nullptr`,
		bool	gentle = `false`
	)		const

inline

Run only the "open" heuristic on a pin.

Parameters

pin	GPIO under test.
label	Optional label for logs.
gentle	If true, performs a gentle open check (avoids INPUT_PULLDOWN; uses only unbiased read + PULLUP).

Returns: true if behavior matches an open/floatable net; false if stuck or odd readings.

Definition at line 238 of file PstTestPins.h.

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◆ testPin()

bool PstTestPins::testPin	(	uint8_t	pin,
		Type	type,
		const char *	label = `nullptr`
	)		const

inline

Run the appropriate self-test(s) for a pin based on its Type.

Parameters

pin	ESP32 GPIO number (e.g., 21).
type	Intended role (determines which checks run).
label	Optional user label for messages (e.g., "I2C_SDA"); falls back to "PIN".

Returns: true if all checks for that type pass; false if any check flags an issue.

Dispatch map:

IO: shorted + open + drive/readback
Input: shorted + open (no driving)
Output: shorted + drive/readback
OpenDrain: open-drain pattern (LOW drive, released HIGH)
ADC: calibrated mV reading; warns on near-0 or near-3V3 values
I2C_SDA/SCL:observe idle without our pulls; diagnose missing pull-ups vs. stuck-low
PWM: same as Output minimal toggle
Button: same as Input
UART_RX: UART-aware RX (gentle short/open) then Input checks
UART_TX: UART-aware TX (idle HIGH) then Output checks

Definition at line 143 of file PstTestPins.h.

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◆ testShorted()

bool PstTestPins::testShorted	(	uint8_t	pin,
		const char *	label = `nullptr`,
		bool	gentle = `false`
	)		const

inline

Run only the "shorted" heuristic on a pin.

Parameters

pin	GPIO under test.
label	Optional label for logs.
gentle	If true, performs a gentle short check (avoids INPUT_PULLDOWN; uses only unbiased read + PULLUP).

Returns: true if not obviously stuck; false if likely shorted.

Definition at line 250 of file PstTestPins.h.

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The documentation for this class was generated from the following file:

C:/Users/patfl/AppData/Local/Arduino15/libraries/LccFusionCore/src/PstTestPins.h

Public Types

Public Member Functions

Static Public Member Functions

Private Member Functions

Static Private Member Functions

Detailed Description

Member Enumeration Documentation

◆ Type

Member Function Documentation

◆ _hasInternalPulls()

◆ _isInputOnly()

◆ _testAdc()

◆ _testDriveRead()

◆ _testI2cLineCheck()

◆ _testOpen()

◆ _testOpenDrain()

◆ _testShorted()

◆ _testUartTx()

◆ init_led()

◆ set_led()

◆ testMcpInput()

◆ testOpen()

◆ testPin()

◆ testShorted()