ra8_panel.h File Reference

Active display-panel descriptor for the EK-RA8D2 (ER-TFT070-6). More...

#include <stddef.h>
#include <stdint.h>

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Macros
#define	RA8_INTERNAL_PANEL_SECTION   gnu::section(".sdram_data"),
	Internal section specifier on target ELF binaries.
#define	RA8_BOARD_PANEL_FRAMEBUFFER(name)
	Declare a correctly aligned, sized and placed RGB565 framebuffer for the on-board panel.

Enumerations
enum	ra8_panel_geometry_t : uint16_t {   k_panel_width_px = 1024U ,   k_panel_height_px = 600U ,   k_panel_width_mm = 154U ,   k_panel_height_mm = 86U ,   k_panel_ppi = 169U }
	ER-TFT070-6 geometry as compile-time constants. More...
enum	ra8_panel_timing_t : uint16_t {   k_panel_h_front = 160U ,   k_panel_h_back = 160U ,   k_panel_h_sync = 4U ,   k_panel_v_front = 12U ,   k_panel_v_back = 23U ,   k_panel_v_sync = 3U }
	ER-TFT070-6 RGB timing (porches + sync); active size = the geometry. More...
enum	ra8_panel_framebuffer_t : uint16_t { k_ra8_board_fb_align_bytes = 64U }
	How a framebuffer for this panel must be laid out in memory. More...

Detailed Description

Active display-panel descriptor for the EK-RA8D2 (ER-TFT070-6).

BSP description of the display wired to the EK-RA8D2 Parallel Graphics Expansion Board 1: the ER-TFT070-6, a 7.0" 1024x600 IPS panel driven RGB565 through the GLCDC. Panel-agnostic code (the shared UI, the host preview) reads its geometry from here rather than hardcoding pixels.

Each board package exposes its own ra8_panel.h; the build selects the active panel through the include path (no preprocessor selection), so a different board – e.g. a future e-reader – swaps in its own descriptor without touching the UI.

Holds the full panel description: UI-facing geometry plus the GLCDC RGB timing (porches / sync). The geometry + timing values here are plain constants (host-includable); the GLCDC-typed timing instance the HAL consumes lives in the companion ra8_panel_timing.h (target-only, since it pulls in the HAL type).

Self-contained (no MCU / FSP includes) so host-side previews include it unchanged.

Copyright

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

Since

0.1.0

Definition in file ra8_panel.h.

Macro Definition Documentation

RA8_BOARD_PANEL_FRAMEBUFFER

#define RA8_BOARD_PANEL_FRAMEBUFFER

(

name

)

Value:

[[RA8_INTERNAL_PANEL_SECTION gnu::aligned(k_ra8_board_fb_align_bytes)]] static uint16_t          \
  name[(size_t)k_panel_height_px * (size_t)k_panel_width_px]

Declare a correctly aligned, sized and placed RGB565 framebuffer for the on-board panel.

Expands to a file-scope static array of k_panel_height_px x k_panel_width_px 16-bit pixels, aligned to k_ra8_board_fb_align_bytes so the GLCDC's AXI bursts fetch cleanly, and placed in .sdram_data – the external-SDRAM output section every EK-RA8D2 linker script defines. All three are board facts, and none of them is checkable by the API that consumes the pointer: the wrong alignment is torn scanout, and 1.2 MiB of surface does not fit in on-chip SRAM at all.

This is the one case the project style rules name as macro-legal – reducing duplicated code – because the alternative, a library-owned array behind an accessor, would fix the size at library build time and cost every application the memory whether it drives the panel or not.

An application drawing into a smaller scratch surface declares its own array instead, but should still take the alignment from k_ra8_board_fb_align_bytes rather than writing 64 again.

Parameters

[in]

name

Identifier for the declared array (a token, not a value).

Precondition

ra8_panel.h is included and the app targets the on-board panel.

Used at file scope; the expansion declares a static object.

The app's linker script defines a .sdram_data output section (the shared board script does).

Postcondition

name is a framebuffer the GLCDC can scan out without tearing.

Roughly 1.2 MiB of external SDRAM is reserved, outside the image.

Note

Not thread-safe in any sense – it is a declaration.

Warning

Omitting the alignment is not a compile error and not a runtime error; it is torn scanout. Prefer this macro over hand-writing the attributes.

Example:

RA8_BOARD_PANEL_FRAMEBUFFER(s_framebuffer);
// ... later, at init:
(void)ra8_gfx_init(s_framebuffer, k_panel_width_px, k_panel_height_px);

See also

k_ra8_board_fb_align_bytes The alignment this applies.

Definition at line 165 of file ra8_panel.h.

RA8_INTERNAL_PANEL_SECTION

#define RA8_INTERNAL_PANEL_SECTION   gnu::section(".sdram_data"),

Internal section specifier on target ELF binaries.

Definition at line 116 of file ra8_panel.h.

Enumeration Type Documentation

ra8_panel_framebuffer_t

enum ra8_panel_framebuffer_t : uint16_t

How a framebuffer for this panel must be laid out in memory.

The GLCDC fetches scanlines over AXI in bursts, and a framebuffer whose base is not 64-byte aligned splits every burst – which shows up as torn scanout, not as an error. Nothing in the API can catch it, so the number has to be stated where a consumer will find it. Before this existed, thirteen example files each declared their own = 64U under a different name (k_app_fb_align_bytes, k_cm_fb_align, k_wd_fb_align, ...), every one carrying the same copied comment – the tell that the fact had been copied rather than derived.

Use RA8_BOARD_PANEL_FRAMEBUFFER for a full-panel surface. An application drawing into a smaller scratch surface declares its own array but should still take the alignment from here.

Invariant

k_ra8_board_fb_align_bytes is a power of two and at least the AXI burst length the GLCDC issues.

[[gnu::aligned(k_ra8_board_fb_align_bytes)]] static uint16_t s_scratch[64 * 64];

See also

RA8_BOARD_PANEL_FRAMEBUFFER Declares a correctly shaped full-panel one.

ra8_panel_geometry_t The panel's pixel budget.

Since

0.1.0

Enumerator
k_ra8_board_fb_align_bytes	GLCDC AXI burst alignment, in bytes.

Definition at line 107 of file ra8_panel.h.

ra8_panel_geometry_t

enum ra8_panel_geometry_t : uint16_t

ER-TFT070-6 geometry as compile-time constants.

The resolution is the hard pixel budget for any UI. The physical fields drive design rules: size touch targets and fonts in millimetres, not just pixels, because the panel PPI is far below a laptop display and the glass does no supersampling. PPI = k_panel_width_px / (k_panel_width_mm / 25.4), which for this panel is about 169. Physical values are approximate – confirm against the ER-TFT070-6 datasheet.

Since

0.1.0

Enumerator
k_panel_width_px	Native width (pixels).
k_panel_height_px	Native height (pixels).
k_panel_width_mm	Active-area width (mm, approx).
k_panel_height_mm	Active-area height (mm, approx).
k_panel_ppi	Pixels per inch (approx).

Definition at line 50 of file ra8_panel.h.

ra8_panel_timing_t

enum ra8_panel_timing_t : uint16_t

ER-TFT070-6 RGB timing (porches + sync); active size = the geometry.

Per the LVGL EK-RA8D2 reference for this panel (these differ from the generic 1024x600 values: h_back 140->160, h_sync 20->4, v_back 20->23). Assembled into the HAL's ra8_glcdc_timing_t in ra8_panel_timing.h.

Since

0.1.0

Enumerator
k_panel_h_front	Horizontal front porch (px).
k_panel_h_back	Horizontal back porch (px).
k_panel_h_sync	HSYNC pulse width (px clocks).
k_panel_v_front	Vertical front porch (lines).
k_panel_v_back	Vertical back porch (lines).
k_panel_v_sync	VSYNC pulse width (lines).

Definition at line 68 of file ra8_panel.h.