avsa242 / bt81x-spin

P8X32A/Propeller, P2X8C4M64P/Propeller 2 driver object for the Bridgetek BT815/816 Advanced Embedded Video Engine (EVE)

bt81x-spin

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This is a P8X32A/Propeller driver object for the Bridgetek BT81x series Advanced Embedded Video Engine (EVE)

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

• SPI connection at 20MHz W/10MHz R (P1), up to 30MHz (P2)
• Graphics primitives: Lines, Points, Text Strings (w/optional wrapping), Numbers (base 2..36), Boxes
• Widgets: Buttons, Dials, Gauges, Gradients (w/or w/o alpha-blending), Keyboard keys, Progress bars, Scroll bars, Sliders, Spinners, Toggle switches
• Set color of primitives, widgets, clear-screen color
• Set panel brightness
• Set scissor clip region
• Screen rotation
• Touchscreen: define tags for display regions, read touch coordinates, read tagged area currently touched, set resistive touch sensitivty, set touch ADC oversampling factor, built-in EVE TS calibration, read/write calibration matrix (includes demo code to write calibration to MCU EE/Flash)
• Set display-specific timings simply by #including the correct file for your display
• Use custom fonts (generated with EVE asset builder or equivalent)

Requirements

• BT815/816-based board

P1/SPIN1:

• spin-standard-library
• 1 extra core/cog for the PASM SPI engine

P2/SPIN2:

• 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	Build OK (untested)
P2	SPIN2	FlexSpin (6.8.0)	Native/PASM2	OK

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

Hardware compatibility

• Tested with EVE3 (BT815, 816) Matrix orbital 4.3" (Resistive), 5.0" (Capacitive), 7.0" (Capacitive)
• Not tested with earlier (FTxxx) or newer EVE4 (BT817, BT818)

Limitations

• Very early in development - may malfunction, or outright fail to build
• API not considered stable - not advisable to design a product around this
• Single-channel SPI only (doesn't support DSPI, QSPI)
• Doesn't support interrupts
• Doesn't support MIDI/audio
• Custom fonts are currently limited to legacy format and must be embedded in the application, so may require substantial amounts of RAM

bt81x-spin's Issues

Add support for flash chips

EVE3 can read/write SPI flash chips, commonly used to store things like fonts, audio files, etc.

• low-level flash i/o support
• support for displaying bitmaps from flash

Add support for TS calibration

This is likely needed for resistive touch models (816).

Add presets for various available display modules

There should be some preset_() methods in the driver to set it up for some of the display modules available from, e.g., Matrix Orbital, Newhaven. This might be a little more intuitive than having separate files #included by the top-level application.

• Matrix Orbital 3.5" capacitive-touch
• Matrix Orbital 3.5" resistive-touch
• Matrix Orbital 4.3" resistive-touch
• Matrix Orbital 5.0" capacitive-touch
• Matrix Orbital 7.0" capacitive-touch

Add demo for storing TS cal in EE

Currently when touchscreen calibration is performed (resistive models), the results aren't stored anywhere, so it must be done every time the app is started. Add some code to optionally store it in EE (or flash in the case of P2).

Add MIDI support

EVE3 supports some level of MIDI output.

FTBFS using FlexSpin

Fails to build because of missing symbols from the display model/resolution/size-specific files included in the top object. This trick works with OpenSpin because #defines are recognized globally throughout the project, but this isn't the case with FlexSpin - they're only visible to the file they are defined in.

The way timings are specified will have to be structured differently. More memory usage, but a child object containing a DAT block with a structure may be easiest?

Add support for custom fonts

Custom bitmap fonts can be loaded (into flash? RAM? both? verify)

spin1 inter-demo delays inconsistent

Delay units should always be milliseconds; some of the inter-demo delays were inadvertently left at seconds, so the wait time gives the appearance the demo is hung.