#include <HD44780.hh>

Inheritance diagram for HD44780::SR3WSPI:

Collaboration diagram for HD44780::SR3WSPI:

Classes
union	port_t

Public Member Functions
	SR3WSPI (Board::DigitalPin en=Board::D5)

virtual bool	setup ()

virtual void	write4b (uint8_t data)

virtual void	write8b (uint8_t data)

virtual void	set_mode (uint8_t flag)

virtual void	set_backlight (uint8_t flag)

virtual void	write8n (const void *buf, size_t size)

void	set_clock (Clock rate)

void	set_clock (uint32_t freq)

Static Public Member Functions
static Clock	clock (uint32_t freq)

static Clock	cycle (uint16_t ns)

Protected Attributes
port_t	m_port
	Port setting. More...

Driver *	m_next
	List of drivers. More...

Interrupt::Handler *	m_irq
	Interrupt handler. More...

OutputPin	m_cs
	Device chip select pin. More...

Pulse	m_pulse
	Chip select pulse width. More...

uint8_t	m_spcr
	SPI/SPCR hardware control register setting. More...

uint8_t	m_spsr
	SPI/SPSR hardware status register. More...

Static Protected Attributes
static const uint16_t	SHORT_EXEC_TIME = 24

Detailed Description

HD44780 (LCD-II) Dot Matix Liquid Crystal Display Controller/Driver Shift Register 3-Wire Port using SPI (SR3WSPI), 74HC595 (SR[pin]). The enable pulse pin acts as the SPI chip select.

Circuit

                        74HC595    (VCC)
                      +----U----+    |
(LCD D5)------------1-|Q1    VCC|-16-+
(LCD D6)------------2-|Q2     Q0|-15-----------(LCD D4)
(LCD D7)------------3-|Q3    SER|-14-----------(MOSI/D11)
(LCD RS)------------4-|Q4    /OE|-13-----------(GND)
(LCD BT)------------5-|Q5   RCLK|-12-----------(EN/D5)
                    6-|Q6   SCLK|-11-----------(SCK/D13)
                    7-|Q7    /MR|-10-----------(VCC)
                  +-8-|GND   Q6'|--9
                  |   +---------+
                  |      0.1uF
                (GND)-----||----(VCC)
(LCD EN)---------------------------------------(EN/D5)
(LCD RW)---------------------------------------(GND)
(LCD K)----------------------------------------(GND)
(LCD A)-----------------[330]------------------(VCC)

Alternative circuit with 74HC164.

                        74HC164    (VCC)
                      +----U----+    |
(D11/MOSI)--------+-1-|DSA   VCC|-14-+
                  +-2-|DSB    Q7|-13
(LCD D4)------------3-|Q0     Q6|-12
(LCD D5)------------4-|Q1     Q5|-11--------(LCD BT)
(LCD D6)------------5-|Q2     Q4|-10--------(LCD RS)
(LCD D7)------------6-|Q3    /MR|--9-----------(VCC)
                  +-7-|GND    CP|--8-------(SCK/D13)
                  |   +---------+
                  |      0.1uF
                (GND)-----||----(VCC)
(LCD EN)---------------------------------------(EN/D5)
(LCD RW)---------------------------------------(GND)
(LCD K)----------------------------------------(GND)
(LCD A)-----------------[330]------------------(VCC)

Performance

The SPI transfer is so fast that a longer delay is required.

Definition at line 618 of file HD44780.hh.

Constructor & Destructor Documentation

HD44780::SR3WSPI::SR3WSPI ( Board::DigitalPin en = Board::D5 )

Construct HD44780 4-wire serial port connected to given enable and chip select pin. Uses the SPI::MOSI(D11) and SPI:SCK(D13) pins.

Parameters

[in] en enable pulse (Default D5, Tiny/D3)

Definition at line 23 of file HD44780_SR3WSPI.cpp.

Member Function Documentation

static Clock SPI::Driver::clock ( uint32_t freq )

inlinestaticinherited

Calculate SPI clock rate (scale factor) for given frequency.

Parameters

[in] freq device max frequency (in Hz).

Returns: clock rate.

Definition at line 117 of file SPI.hh.

static Clock SPI::Driver::cycle ( uint16_t ns )

inlinestaticinherited

Calculate SPI clock rate (scale factor) for given clock cycle time in nano seconds.

Parameters

[in] ns min device clock cycle time.

Returns: clock rate.

Definition at line 135 of file SPI.hh.

void HD44780::SR3WSPI::set_backlight ( uint8_t flag )

virtual

Set backlight on/off using bt pin.

Parameters

[in] flag.

Implements HD44780::IO.

Definition at line 69 of file HD44780_SR3WSPI.cpp.

void SPI::Driver::set_clock ( Clock rate )

inherited

Set SPI master clock rate.

Parameters

[in] clock rate.

Definition at line 297 of file SPI.cpp.

void SPI::Driver::set_clock ( uint32_t freq )

inlineinherited

Set SPI master clock frequency.

Parameters

[in] freq device max frequency (in Hz).

Definition at line 157 of file SPI.hh.

void HD44780::SR3WSPI::set_mode ( uint8_t flag )

virtual

Set instruction/data mode using given rs pin; zero for instruction, non-zero for data mode.

Parameters

[in] flag.

Implements HD44780::IO.

Definition at line 63 of file HD44780_SR3WSPI.cpp.

bool HD44780::SR3WSPI::setup ( )

virtual

Initiate serial port. Returns false.

Returns: bool.

Implements HD44780::IO.

Definition at line 30 of file HD44780_SR3WSPI.cpp.

void HD44780::SR3WSPI::write4b ( uint8_t data )

virtual

Write LSB nibble to display using serial port.

Parameters

[in] data (4b) to write.

Implements HD44780::IO.

Definition at line 36 of file HD44780_SR3WSPI.cpp.

void HD44780::SR3WSPI::write8b ( uint8_t data )

virtual

Write byte (8bit) to display.

Parameters

[in] data (8b) to write.

Reimplemented from HD44780::IO.

Definition at line 47 of file HD44780_SR3WSPI.cpp.

void HD44780::IO::write8n	(	const void *	buf,
		size_t	size
	)

virtualinherited

Write character buffer to display.

Parameters

[in]	buf	pointer to buffer.
[in]	size	number of bytes in buffer.

Reimplemented in ERM1602_5, Adafruit_I2C_LCD_Backpack, DFRobot_IIC_LCD_Module, MJKDZ_LCD_Module, and SainSmart_LCD2004.

Definition at line 31 of file HD44780_IO.cpp.

Member Data Documentation

OutputPin SPI::Driver::m_cs

protectedinherited

Device chip select pin.

Definition at line 166 of file SPI.hh.

Interrupt::Handler* SPI::Driver::m_irq

protectedinherited

Interrupt handler.

Definition at line 165 of file SPI.hh.

Driver* SPI::Driver::m_next

protectedinherited

List of drivers.

Definition at line 164 of file SPI.hh.

port_t HD44780::SR3WSPI::m_port

protected

Port setting.

Definition at line 694 of file HD44780.hh.

Pulse SPI::Driver::m_pulse

protectedinherited

Chip select pulse width.

Definition at line 167 of file SPI.hh.

uint8_t SPI::Driver::m_spcr

protectedinherited

SPI/SPCR hardware control register setting.

Definition at line 173 of file SPI.hh.

uint8_t SPI::Driver::m_spsr

protectedinherited

SPI/SPSR hardware status register.

Definition at line 174 of file SPI.hh.

const uint16_t HD44780::SR3WSPI::SHORT_EXEC_TIME = 24

staticprotected

Execution time delay (us).

Definition at line 670 of file HD44780.hh.

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

libraries/HD44780/HD44780.hh
libraries/HD44780/HD44780_SR3WSPI.cpp

Classes

Public Member Functions

Static Public Member Functions

Protected Attributes

Static Protected Attributes

Detailed Description

Circuit

Performance

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation