SegDriver_HT1621 Class Reference

HT1621 LCD segment display driver. More...

#include <SegDriver_HT1621.h>

Inheritance diagram for SegDriver_HT1621:

Public Member Functions
	SegDriver_HT1621 (SegTransport3Wire &transport, uint8_t chipselect)
	Constructor for HT1621 segment driver.
void	flush (uint8_t startAddr, uint8_t length) override
	Flush specific range of buffered changes to the display.
virtual void	flush ()
	Flush all buffered changes to the display.
virtual void	flush (uint8_t startAddr, uint8_t length)
	Flush specific range of buffered changes to the display.
Public Member Functions inherited from SegDriver_3Wire
	SegDriver_3Wire (SegTransport3Wire &transport, uint8_t chipselect)
	Constructor for 3-wire serial LCD driver.
void	init () override
	Initialize GPIO pins for communication.
void	on () override
	Turn the display on.
void	off () override
	Turn the display off.
void	command (uint8_t command) override
	Send command to the controller.
Public Member Functions inherited from SegLCDLib
virtual	~SegLCDLib ()
	Virtual destructor to ensure proper cleanup in derived classes.
virtual void	clear ()
	Clear all visible segments on the display.
void	home ()
	Set cursor to 0, 0 without clear display.
virtual void	setCursor (uint8_t row, uint8_t col)
	Set cursor on exact digit.
virtual size_t	write (uint8_t)
void	initBacklight (int8_t backlightPin, BacklightMode backlightMode=BACKLIGHT_DIGITAL, bool backlightActiveHigh=true)
	Initialize GPIO backlight control.
virtual void	setBacklight (bool state)
	Set backlight state (on/off).
virtual void	setBacklight (int brightness)
	Set backlight brightness (0-255).
void	setAutoFlush (bool enable)
	Enable or disable autoflush mode.
bool	getAutoFlush () const
	Get current autoflush state.
const uint8_t *	getRamBuffer () const
	Get pointer to internal RAM buffer (read-only).
size_t	getRamBufferSize () const
	Get size of internal RAM buffer in bytes.

Protected Member Functions
void	_setMode (ModeDrive drive=MODE_DRIVE_14, ModeBias bias=MODE_BIAS_13)
	Set the mode of the display.
Protected Member Functions inherited from SegDriver_3Wire
virtual void	_writeRam (uint8_t *data, size_t length, uint8_t address)
	Low-level method to write a data buffer to display RAM.
void	_writeRam (uint8_t data, uint8_t address=0)
	Write multiple bytes to RAM starting at specified address.
virtual void	_writeRam (uint8_t *data, size_t length, uint8_t address)=0
	Write multiple bytes to RAM starting at specified address.
Protected Member Functions inherited from SegLCDLib
void	_setFlag (uint8_t mask)
	Set a specific flag bit.
void	_clearFlag (uint8_t mask)
	Clear a specific flag bit.
bool	_isFlagSet (uint8_t mask) const
	Check if a specific flag bit is set.
void	_clearAllFlags ()
	Clear all flags.
bool	_dotWrite (uint8_t ch, int8_t minCol, int8_t maxCol, int8_t ramOffset)
	Write decimal point.
void	_dotClearCur (int8_t minCol, int8_t maxCol)
	Clear current decimal (overwrite).
void	_colonClearIfNotFlagged (uint8_t ch, uint8_t colonCol, uint8_t colonFlag)
	Clear colon if its flag is not set.
virtual void	_setDecimal (uint8_t, uint8_t, bool)
	Virtual method for setting decimal point.
virtual void	_setColon (uint8_t, uint8_t, bool)
	Virtual method for setting colon.
void	_allocateBuffer (size_t size)
	Allocate RAM buffer for display data.
void	_writeRamMasked (uint8_t data, uint8_t address, uint8_t mask=0xFF)
	Write to display RAM with nibble-aware masking support.
void	_writeRam (uint8_t data, uint8_t address=0)
	Low-level method to write a single byte to display RAM.
uint8_t	_get_char_value (char ch)
	Helper method to convert a character to its segment representation.
uint16_t	_get_16char_value (char ch)
	Helper method to convert a character to its 16-segment representation.

Static Protected Attributes
static constexpr uint8_t	MAX_ADDRESS = 30
	Last valid start HW nibble address for byte write.
Static Protected Attributes inherited from SegLCDLib
static constexpr uint8_t	FLAG_PENDING_DOT = 0x80
	Common flag for decimal handling when RAM offset is 0.

Private Attributes
ModeDrive	_drive
	Current drive mode.

Additional Inherited Members
Public Types inherited from SegLCDLib
enum	BacklightMode { BACKLIGHT_DIGITAL , BACKLIGHT_PWM }
	Backlight mode for GPIO control. More...
Protected Attributes inherited from SegDriver_3Wire
SegTransport3Wire &	_transport
uint8_t	_cs
	Chip select pin for the display.
Protected Attributes inherited from SegLCDLib
bool	_autoFlush = true
	Autoflush mode enabled flag (default: true for LCD API 1.0 compatibility).
int8_t	_backlightPin = -1
	Backlight GPIO pin (-1 if disabled)
BacklightMode	_backlightMode = BACKLIGHT_DIGITAL
	Backlight mode (DIGITAL or PWM)
bool	_backlightActiveHigh = true
	Backlight active high flag.
uint8_t	_backlightBrightness = 0
	Cached backlight brightness.
uint8_t	_displayFlags = 0
	LEDC channel for old ESP32 Arduino Core (2.0.x)
uint8_t *	_ramBuffer = nullptr
	Dynamic RAM buffer for display data (allocated by derived classes).
size_t	_ramBufferSize = 0
	Size of allocated RAM buffer in bytes.
uint8_t	_cursorRow = 0
	Current Row.
uint8_t	_cursorCol = 0
	Current Column.

Detailed Description

HT1621 LCD segment display driver.

This driver extends the 3-wire base driver with HT1621-specific features including TONE commands and configurable BIAS/DRIVE modes.

Constructor & Destructor Documentation

SegDriver_HT1621()

SegDriver_HT1621::SegDriver_HT1621	(	SegTransport3Wire &	transport,
		uint8_t	chipselect
	)

Constructor for HT1621 segment driver.

Parameters

chipselect	Chip select pin for the display
data	Data pin for the display
write	Write clock pin for the display
read	Read clock pin for the display (optional, default is -1)

Member Function Documentation

_setMode()

void SegDriver_HT1621::_setMode ( ModeDrive  drive = MODE_DRIVE_14, ModeBias  bias = MODE_BIAS_13  )

protected

Set the mode of the display.

This method sets the drive and bias modes for the display.

Parameters

drive	Drive mode (default is MODE_DRIVE_14)
bias	Bias mode (default is MODE_BIAS_13)

flush() [1/3]

void SegLCDLib::flush ( )

virtual

Flush all buffered changes to the display.

Writes the entire display buffer to the hardware. This is useful when autoflush is disabled to batch multiple write() calls into a single hardware update cycle.

Safe to call even when autoflush is enabled (no effect).

See also

setAutoFlush()

Reimplemented from SegLCDLib.

flush() [2/3]

void SegLCDLib::flush ( uint8_t  startAddr, uint8_t  length  )

virtual

Flush specific range of buffered changes to the display.

Writes a specific address range from the display buffer to hardware. This is an advanced API for optimizing updates when only part of the display needs to be refreshed.

For example, to update only the first row of a multi-row display:

lcd.flush(0, 6);  // Update first 6 bytes (row 0)

Safe to call even when autoflush is enabled (no effect).

Parameters

startAddr	Starting buffer address in bytes (RAM buffer index)
length	Number of bytes to flush

See also

setAutoFlush()

Reimplemented from SegLCDLib.

flush() [3/3]

void SegDriver_HT1621::flush ( uint8_t  startAddr, uint8_t  length  )

overridevirtual

Flush specific range of buffered changes to the display.

Optimized implementation for HT1621 that loops through each address since the 3-wire protocol doesn't support bulk write.

Parameters

startAddr	Starting buffer address in bytes (RAM buffer index)
length	Number of bytes to flush

Reimplemented from SegLCDLib.

Field Documentation

_drive

ModeDrive SegDriver_HT1621::_drive

private

Current drive mode.

MAX_ADDRESS

constexpr uint8_t SegDriver_HT1621::MAX_ADDRESS = 30

staticconstexprprotected

Last valid start HW nibble address for byte write.

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

• src/SegDriver_HT1621.h
• src/SegDriver_HT1621.cpp