E-ink backend (IT8951) for the display PAL. More...

#include <stdint.h>
#include "ra8_display_pal.h"

Include dependency graph for ra8_display_pal_eink.h:

This graph shows which files directly or indirectly include this file:

Functions
uint8_t	ra8_display_pal_eink_luma_from_rgb565 (uint16_t px)
	Convert one RGB565 pixel to an 8 bpp greyscale (Rec.601 luma).

Variables
const display_backend_iface_t	k_display_backend_eink_it8951
	E-ink (IT8951) backend vtable.

Detailed Description

E-ink backend (IT8951) for the display PAL.

Tag: [Ring 4 / PAL] {World: NS}

Exports the const display_backend_iface_t instance that drives an IT8951-compatible e-ink panel through libs/ra8_hal/src/ra8_epaper.c. Apps select this backend by setting display_cfg_t.iface = &k_display_backend_eink_it8951; and pass the BSP's IT8951 descriptor (a const ra8_epaper_cfg_t*) through display_cfg_t.panel_timing. The backend accepts the same canonical RGB565 framebuffer the LCD backend uses, so swapping panels is a config change – the app's drawing code is unchanged.

On display_flush the backend converts the requested rectangle from RGB565 to the IT8951's native 8 bpp greyscale (Rec.601 luma) and pushes it to the controller, then refreshes with the waveform mapped from the caller's display_refresh_hint_t (fast -> A2, quality -> GC16, init -> INIT). On-panel HIL validation needs an IT8951 panel on the bench; the vtable + conversion are host-verified against the fake-backed ra8_epaper driver.

Copyright: Copyright (c) 2026 Brighton Sikarskie SPDX-License-Identifier: MIT

Since: 0.1.0

Definition in file ra8_display_pal_eink.h.

Function Documentation

◆ ra8_display_pal_eink_luma_from_rgb565()

uint8_t ra8_display_pal_eink_luma_from_rgb565 ( uint16_t px )

Convert one RGB565 pixel to an 8 bpp greyscale (Rec.601 luma).

Internal-but-exposed so host unit tests can pin the conversion the e-ink flush path relies on. Expands the 5/6/5 channels to 8 bits by bit-replication, then applies the integer Rec.601 weights (77/150/29, /256). Pure white maps to 255 and pure black to 0.

Parameters

[in] px Source pixel in RGB565 (little-endian field layout).

Returns: The 8 bpp greyscale value.

Return values

0	For px == 0x0000 (black).
255	For px == 0xFFFF (white).

Precondition: None.; None.

Postcondition: No state mutated.; Return depends solely on px.

Note: Pure function; thread-safe.

Since: 0.1.0

Definition at line 122 of file ra8_display_pal_eink.c.

References k_eink_b5_mask, k_eink_g6_mask, k_eink_g6_shift, k_eink_luma_b, k_eink_luma_g, k_eink_luma_r, k_eink_luma_shift, k_eink_r5_mask, and k_eink_r5_shift.

Referenced by internal_eink_pack_row_4bpp().

Variable Documentation

◆ k_display_backend_eink_it8951

const display_backend_iface_t k_display_backend_eink_it8951

extern

E-ink (IT8951) backend vtable.

init brings up the IT8951 over SPI via ra8_epaper_init (using the ra8_epaper_cfg_t supplied in display_cfg_t.panel_timing); get_framebuffer hands back the app's RGB565 buffer; flush converts the dirty rectangle to 8 bpp luma and refreshes the panel; clear fills the framebuffer; deinit sleeps the panel.

Since: 0.1.0

Definition at line 645 of file ra8_display_pal_eink.c.

Referenced by main().

Functions

Variables

Detailed Description

Function Documentation

◆ ra8_display_pal_eink_luma_from_rgb565()

Variable Documentation

◆ k_display_backend_eink_it8951