## Summary
Adds Xteink X3 hardware support to CrossPoint Reader. The X3 uses the
same SSD1677 e-ink controller as the X4 but with a different panel
(792x528 vs 800x480), different button layout, and an I2C fuel gauge
(BQ27220) instead of ADC-based battery reading.
All X3-specific behavior is gated by runtime device detection — X4
behavior is unchanged.
Depends on community-sdk X3 support: open-x4-epaper/community-sdk#19
(merged).
## Changes
### HAL Layer
**HalGPIO** (`lib/hal/HalGPIO.cpp/.h`)
- I2C-based device fingerprinting at boot: probes for BQ27220 fuel
gauge, DS3231 RTC, and QMI8658 IMU to distinguish X3 from X4
- Detection result cached in NVS for fast subsequent boots
- Exposes `deviceIsX3()` / `deviceIsX4()` helpers used throughout the
codebase
- X3 button mapping (7 GPIOs vs X4's layout)
- USB connection detection and wake classification for X3
**HalDisplay** (`lib/hal/HalDisplay.cpp/.h`)
- Calls `einkDisplay.setDisplayX3()` before init when X3 is detected
- Requests display resync after power button / flash wake events
- Runtime display dimension accessors (`getDisplayWidth()`,
`getDisplayHeight()`, `getBufferSize()`)
- Exposed as global `display` instance for use by image converters
**HalPowerManager** (`lib/hal/HalPowerManager.cpp/.h`)
- X3 battery reading via I2C fuel gauge (BQ27220 at 0x55, SOC register)
- X3 power button uses GPIO hold for deep sleep
### Display & Rendering
**GfxRenderer** (`lib/GfxRenderer/GfxRenderer.cpp/.h`)
- Buffer size and display dimensions are now runtime values (not
compile-time constants) to support both panel sizes
- X3 anti-aliasing tuning: only the darker grayscale level is applied to
avoid washed-out text on the X3 panel. X4 retains both levels via
`deviceIsX4()` gate
**Image Converters** (`lib/JpegToBmpConverter`, `lib/PngToBmpConverter`)
- Cover image prescale target uses runtime display dimensions from HAL
instead of hardcoded 800x480
### UI Themes
**BaseTheme / LyraTheme** (`src/components/themes/`)
- X3 button position mapping for the different physical layout
- Adjusted UI element positioning for 792x528 viewport
### Boot & Init
**main.cpp**
- X3 hardware detection logging
- Adjusted init sequence for X3 (no `HalSystem::begin()` dependency on
X3 path)
**HomeActivity**
- Uses runtime `renderer.getBufferSize()` instead of static
`GfxRenderer::getBufferSize()`
FYI I did not add support for the gyro page turner. That can be it's own
PR.
## Summary
* **What is the goal of this PR?**
The goal of this PR is to deliver a fix for or at least mitigate the
impact of the issue described in #561
* **What changes are included?**
This PR includes a new option "Sunlight Fading Fix" under "Settings ->
Display".
When set to ON, we will disable the displays analog supply voltage after
every update and turn it back on before the next update.
## Additional Context
* Until now, I was only able to do limited testing because of limited
sunlight at my location, but the fix seems to be working. I'll also
attach a pre-built binary based on 0.16.0 (current master) with the fix
applied to the linked ticket, as building this fix is a bit annoying
because the submodule open-x4-sdk also needs an update.
* [PR in
open-x4-sdk](https://github.com/open-x4-epaper/community-sdk/pull/15)
needs to be merged first, we also need to add another commit to this
here PR, updating this dependency.
* I decided to hide this behind a default-OFF option. While I'm not
really concerned that this fix might potentially damage the display,
someone more knowledgeable on E-Ink technology could maybe have a look
at this.
* There's a binary attached in the linked issue, if someone has the
required sunlight to test this in-depth.
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? _**NO**_
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
Extracted some changes from
https://github.com/crosspoint-reader/crosspoint-reader/pull/500 to make
reviewing easier
This PR adds HAL (Hardware Abstraction Layer) for display and GPIO
components, making it easier to write a stub or an emulated
implementation of the hardware.
SD card HAL will be added via another PR, because it's a bit more
tricky.
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? **NO**
