avsa242 / hd44780-spin

Parallax P8X32A/Propeller, P2X8C4M64P/Propeller 2 driver object for the Hitachi HD44780 LCD

hd44780-spin

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This is a P8X32A/Propeller, P2X8C4M64P/Propeller 2 driver object for the HD44780 LCD

IMPORTANT: This software is meant to be used with the spin-standard-library (P8X32A) or p2-spin-standard-library (P2X8C4M64P). Please install the applicable library first before attempting to use this code, otherwise you will be missing several files required to build the project.

Salient Features

• I2C connection at ~30kHz (P1: SPIN I2C), 100kHz (P1: PASM I2C, P2)
• Backlight control
• Set cursor visibility mode (block/underscore/blinking/no blinking)
• Set display visibility mode (independent of display RAM contents)
• Set cursor position
• Enable/disable processing of control chars at runtime
• Support for alternate I2C addresses

Requirements

P1/SPIN1:

• spin-standard-library
• PCF8574 driver (provided by the spin-standard-library)
• For I2C-connected displays: 1 extra core/cog for the PASM PCF8574 driver (none if using the bytecode-based driver)
• terminal.common.spinh (provided by the spin-standard-library)

P2/SPIN2:

• p2-spin-standard-library
• PCF8574 driver (provided by the p2-spin-standard-library)
• terminal.common.spin2h (provided by the p2-spin-standard-library)

Compiler Compatibility

Processor	Language	Compiler	Backend	Status
P1	SPIN1	FlexSpin (6.8.0)	Bytecode	OK
P1	SPIN1	FlexSpin (6.8.0)	Native/PASM	OK
P2	SPIN2	FlexSpin (6.8.0)	NuCode	OK
P2	SPIN2	FlexSpin (6.8.0)	Native/PASM2	OK

(other versions or toolchains not listed are not supported, and may or may not work)

Limitations

• Very early in development - may malfunction, or outright fail to build

hd44780-spin's Issues

Add default I/O configuration to the driver

Add symbols for I/O pins, etc so driver setup can be done using constant overrides in the parent.

Positioning code hardcoded for 2x16 displays

The positioning code has only been tested with 2x16 displays.
Width and height params should be specifiable at driver startup. (edit: this should have its own issue...it isn't strictly necessary for adding other display size support)

Add support for SPI, Serial, Parallel interfaces

"Backpacks" are available that provide an SPI connection to the display.
The native parallel interface should also be supported.

• SPI
• Async serial (exists in spin-standard-library as display.lcd.serial)
• Parallel