IT8951 e-paper full + partial refresh demo through the display PAL. More...

#include <stddef.h>
#include <stdint.h>
#include "ra8_board_ek_ra8d2.h"
#include "ra8_boot_entry.h"
#include "ra8_cgc.h"
#include "ra8_display_pal.h"
#include "ra8_display_pal_eink.h"
#include "ra8_epaper.h"
#include "ra8_epd_cal.h"
#include "ra8_err.h"
#include "ra8_io_spi_bus.h"
#include "ra8_io_spi_bus_spi_b.h"
#include "ra8_isr.h"
#include "ra8_mstp.h"
#include "ra8_panel.h"
#include "ra8_port_constants.h"
#include "ra8_port_utils.h"
#include "ra8_spi.h"
#include "ra8_time.h"

Include dependency graph for main.c:

Enumerations
enum	ep_geom_t : uint16_t { k_ep_panel_w = 128U , k_ep_panel_h = 128U , k_ep_cell = 16U }
	Panel + framebuffer geometry. More...
enum	ep_region_t : uint16_t { k_ep_box_x = 48U , k_ep_box_y = 48U , k_ep_box_w = 32U , k_ep_box_h = 32U }
	Sub-rectangle updated by the partial refresh. More...
enum	ep_color_t : uint16_t { k_ep_white = 0xFFFFU , k_ep_black = 0x0000U }
	RGB565 shades used by the test pattern. More...
enum	ep_bus_t : uint32_t { k_ep_spi_channel = 0U , k_ep_spi_baud_hz = 10000000U , k_ep_uart_baud = 115200U , k_ep_powerup_ms = 50U , k_ep_heartbeat_ms = 500U }
	SPI + UART bring-up parameters. More...
enum	ep_fmt_t : uint8_t { k_ep_line_max = 48U , k_ep_dec_digits = 10U , k_ep_radix = 10U , k_ep_cr = '\r' , k_ep_lf = '\n' }
	UART line-formatting constants. More...
enum	ep_pin_t : uint16_t { k_ep_reset_pin = ((ra8_port_pin_t)(((uint16_t)(k_ra8_port_4) << 8) \| (uint16_t)(k_ra8_pin_0))) , k_ep_hrdy_pin = ((ra8_port_pin_t)(((uint16_t)(k_ra8_port_4) << 8) \| (uint16_t)(k_ra8_pin_1))) }
	IT8951 control GPIOs on the (hypothetical) e-paper carrier. More...
enum	ep_vcom_limits_t : uint16_t { k_ep_vcom_min_mv = 200U , k_ep_vcom_max_mv = 4000U }
	The plausible VCOM magnitude window for this panel family. More...

Functions
static uint16_t	ep_checker_px (uint16_t x, uint16_t y)
	Checkerboard colour for a framebuffer pixel.
static bool	ep_region_fits (uint16_t x, uint16_t y, uint16_t w, uint16_t h, uint16_t pw, uint16_t ph)
	Whether a rectangle (w, h >= 1) fits wholly inside the panel.
static bool	ep_flush_ok (ra8_err_t init_err, ra8_err_t full_err, ra8_err_t part_err)
	PASS verdict: every stage returned k_ra8_ok.
static uint32_t	ep_u32_to_dec (uint8_t *buf, uint32_t val)
	Write the decimal digits of val into buf; return the count.
static void	ep_panic_halt (void)
	Halt forever with the red board LED on.
static void	ep_emit (const uint8_t *data, uint32_t len)
	Emit a NUL-free byte span on the SCI console (best effort).
static void	ep_bringup_core (uint32_t *out_pclka_hz)
	Bring up clocks, MSTP, SysTick, the console and both LEDs.
static void	ep_bringup_panel_bus (uint32_t pclka_hz)
	Configure the panel GPIOs + SPI bus and fill s_epaper_cfg.
static ra8_err_t	ep_vcom_get (void ctx, uint16_t out_mv)
	ra8_epd_cal read seam bound to the IT8951 VCOM command.
static ra8_err_t	ep_vcom_set (void *ctx, uint16_t mv)
	ra8_epd_cal write seam bound to the IT8951 VCOM command.
static bool	ep_calibrate_vcom (void)
	Resolve this panel's VCOM and programme it, or refuse to draw.
static void	ep_paint_checker (void)
	Paint the whole framebuffer with the checkerboard pattern.
static void	ep_paint_region_black (void)
	Blacken the partial-refresh sub-rectangle in the framebuffer.
static void	ep_report_stage (const char *label, uint32_t dt_ms, uint32_t pixels)
	Print epaper: <label> ms=<dt> px=<count> on the console.
static void	ep_report_init (void)
	Print epaper: init ok panel=<w>x<h>.
static void	ep_run_refresh_cycle (ra8_err_t full_err, ra8_err_t part_err)
	Drive the full (checker/GC16) then partial (box/A2) refresh cycle.
void	main (void)
	Application entry: e-ink full + partial refresh through the PAL.

Variables
static uint16_t	s_framebuffer [(uint32_t) k_ep_panel_w *(uint32_t) k_ep_panel_h]
	RGB565 framebuffer in SRAM, 64-byte AXI-burst aligned.
static ra8_io_spi_bus_t	s_spi_bus
	ra8_io SPI-bus handle bound to SPI_B channel 0.
static ra8_epaper_cfg_t	s_epaper_cfg
	IT8951 descriptor handed to the e-ink backend via panel_timing.
static display_handle_t *	s_display = nullptr
	PAL handle returned by display_init.
static display_caps_t	s_caps
	Cached backend caps + framebuffer descriptor.
static display_fb_t	s_fb
static const uint8_t	k_ep_msg_pass [] = "epaper: PASS\r\n"
	PASS / FAIL banners.
static const uint8_t	k_ep_msg_fail [] = "epaper: FAIL\r\n"
static const uint8_t	k_ep_msg_no_vcom [] = "epaper: NO TRUSTED VCOM -- panel left dark\r\n"
	Banner for the INV-VCOM-1 refusal.

Detailed Description

IT8951 e-paper full + partial refresh demo through the display PAL.

Tag: [Ring 6 / APP] {World: S}

End-to-end example for the e-ink display path (#256): it drives an IT8951-compatible e-paper panel entirely through libs/ra8_display_pal's e-ink backend (k_display_backend_eink_it8951), which sits on the ra8_epaper HAL driver over an injected ra8_io_spi_bus seam. The app itself never names ra8_epaper_* – it paints a canonical RGB565 framebuffer and calls the same six PAL entry points the LCD demo uses.

Flow:

Bring up clocks, MSTP, SysTick, the SCI console and two LEDs.
Configure the panel's /RESET (output) and HRDY (input) GPIOs, bring up SPI_B channel 0 (mode 0, 10 MHz – under the IT8951's 24 MHz ceiling), and bind it into the ra8_epaper bus seam via ra8_io_spi_bus.
display_init with the e-ink backend + the BSP-style IT8951 descriptor carried in display_cfg_t.panel_timing.
Paint a checkerboard test pattern and FULL-refresh it (GC16 quality), timing the flush over SysTick and reporting it on the UART.
Blacken a sub-region and PARTIAL-refresh just that rectangle (A2 fast), again timing + reporting.
display_deinit sleeps the panel; print epaper: PASS.

Hardware / off-target

The EK-RA8D2 ships a parallel-RGB TFT, not e-paper, so on-panel HIL is pending an IT8951 carrier on the bench (see README). tools/ra8_emulator models the IT8951 as an SPI device (--eink): it answers HRDY, the GET_DEV_INFO drain and the LUTAFSR "LUT idle" poll, so this whole path runs headlessly to its epaper: PASS banner – EIL == HIL.

The reported refresh times are informational: on silicon a GC16 full refresh is hundreds of milliseconds and an A2 partial tens; under ra8_emulator the modelled controller completes instantly, so the numbers are near zero. The PASS verdict never depends on a timing value.

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

Since: 0.1.0

Definition in file main.c.

Enumeration Type Documentation

◆ ep_bus_t

enum ep_bus_t : uint32_t

SPI + UART bring-up parameters.

Since: 0.1.0

Enumerator
k_ep_spi_channel	SPI_B channel 0 drives the panel.
k_ep_spi_baud_hz	10 MHz (<= IT8951 24 MHz ceiling).
k_ep_uart_baud	SCI console baud.
k_ep_powerup_ms	PLL / panel settle before init.
k_ep_heartbeat_ms	LED heartbeat period after PASS.

Definition at line 118 of file main.c.

◆ ep_color_t

enum ep_color_t : uint16_t

RGB565 shades used by the test pattern.

Since: 0.1.0

Enumerator
k_ep_white	Full white (maps to 8bpp 255).
k_ep_black	Full black (maps to 8bpp 0).

Definition at line 107 of file main.c.

◆ ep_fmt_t

enum ep_fmt_t : uint8_t

UART line-formatting constants.

Since: 0.1.0

Enumerator
k_ep_line_max	Max chars in one console line.
k_ep_dec_digits	Max decimal digits for a uint32_t.
k_ep_radix	Decimal radix.
k_ep_cr	Ep cr.
k_ep_lf	Ep lf.

Definition at line 132 of file main.c.

◆ ep_geom_t

enum ep_geom_t : uint16_t

Panel + framebuffer geometry.

A modest 128 x 128 8bpp panel keeps the per-pixel SPI streaming fast under ra8_emulator while still exercising a full + partial refresh. RGB565 framebuffer = 128 * 128 * 2 = 32 KiB in SRAM.

Since: 0.1.0

Enumerator
k_ep_panel_w	Panel + framebuffer width (px).
k_ep_panel_h	Panel + framebuffer height (px).
k_ep_cell	Checkerboard cell size (px).

Definition at line 82 of file main.c.

◆ ep_pin_t

enum ep_pin_t : uint16_t

IT8951 control GPIOs on the (hypothetical) e-paper carrier.

These are NOT stock EK-RA8D2 board facts – the EK ships a parallel TFT – so they live in the app, not the board layer. They match the pins the ra8_emulator IT8951 model drives (P4_00 /RESET, P4_01 HRDY). The SPI_B COPI/CIPO/SCK routing for the carrier is documented in the README; ra8_emulator does not require it.

Since: 0.1.0

Enumerator
k_ep_reset_pin	IT8951 /RESET (P4_00).
k_ep_hrdy_pin	IT8951 HRDY (P4_01).

Definition at line 152 of file main.c.

◆ ep_region_t

enum ep_region_t : uint16_t

Sub-rectangle updated by the partial refresh.

Since: 0.1.0

Enumerator
k_ep_box_x	Partial-region left edge (px).
k_ep_box_y	Partial-region top edge (px).
k_ep_box_w	Partial-region width (px).
k_ep_box_h	Partial-region height (px).

Definition at line 94 of file main.c.

◆ ep_vcom_limits_t

enum ep_vcom_limits_t : uint16_t

The plausible VCOM magnitude window for this panel family.

A range, never a value: the range says "no sane panel is calibrated outside this", which is enough to reject a controller reporting 0 or 0xFFFF, while carrying none of the per-unit information that makes a hardcoded VCOM damaging. Panels in this family ship labelled around -1.5 V; the window is deliberately wider than that so a legitimately unusual panel is not locked out.

Invariant: min is non-zero, so a controller reporting zero can never pass the range check.; min <= max.

See also: ra8_epd_cal_limits_mv_t

Since: 0.1.0

Enumerator
k_ep_vcom_min_mv	Lowest plausible magnitude, millivolts.
k_ep_vcom_max_mv	Highest plausible magnitude, millivolts.

Definition at line 243 of file main.c.

Function Documentation

◆ ep_bringup_core()

void ep_bringup_core ( uint32_t * out_pclka_hz )

static

Bring up clocks, MSTP, SysTick, the console and both LEDs.

Parameters

[out] out_pclka_hz Receives PCLKA in Hz (SPI clock source).

Precondition: Reset_Handler ran .data/.bss init.; out_pclka_hz != NULL.

Postcondition: Clocks, MSTP, SysTick, console and LEDs are live.; *out_pclka_hz holds PCLKA in Hz.

Note: Not thread-safe; single-shot helper. Panic-halts on any failure.

Since: 0.1.0

Definition at line 429 of file main.c.

References ep_panic_halt(), k_ep_uart_baud, k_ra8_board_led_blue, k_ra8_board_led_red, k_ra8_clock_id_cpuclk0, k_ra8_clock_id_pclka, k_ra8_ok, ra8_board_led_init(), ra8_board_uart_console_init(), ra8_cgc_get_clock_hz(), ra8_cgc_init(), ra8_mstp_init(), and ra8_time_init().

Referenced by main().

◆ ep_bringup_panel_bus()

void ep_bringup_panel_bus ( uint32_t pclka_hz )

static

Configure the panel GPIOs + SPI bus and fill s_epaper_cfg.

Drives /RESET high (output), configures HRDY as a pulled-up input, brings up SPI_B channel 0 in mode 0 as controller, binds it into an ra8_io_spi_bus and exposes it through the Ring-3 seam the IT8951 descriptor carries.

Parameters

[in] pclka_hz PCLKA in Hz (SPI clock source).

Precondition: ep_bringup_core has run.; pclka_hz != 0.

Postcondition: On success s_epaper_cfg.bus.xfer8 is non-NULL and the panel GPIOs are configured.; s_spi_bus is bound to SPI_B channel 0.

Note: Not thread-safe; single-shot helper. Panic-halts on any failure.

Since: 0.1.0

Definition at line 477 of file main.c.

References ep_panic_halt(), k_ep_hrdy_pin, k_ep_panel_h, k_ep_panel_w, k_ep_reset_pin, k_ep_spi_baud_hz, k_ep_spi_channel, k_ra8_level_high, k_ra8_ok, k_ra8_pull_up, k_ra8_spi_mode_0, ra8_epaper_waveform_cfg_for_lut(), ra8_gpio_input_init(), ra8_gpio_output_init(), ra8_io_spi_bus_as_ops(), ra8_io_spi_bus_bind_spi_b(), ra8_spi_init(), s_epaper_cfg, and s_spi_bus.

Referenced by main().

◆ ep_calibrate_vcom()

bool ep_calibrate_vcom ( void )

static

Resolve this panel's VCOM and programme it, or refuse to draw.

The INV-VCOM-1 gate, and the reason this app cannot simply start flushing after display_init. ra8_epd_cal_resolve walks the controller's own persisted value, then the per-device record, then an operator-supplied value, and fails rather than inventing one; ra8_epd_cal_apply programmes the winner and confirms it by readback. Only then does the driver permit a refresh at all.

The store seams are left unbound on purpose. Reading the per-device record needs a fault-tolerant extra-MRAM probe (a virgin page bus-faults on the first read), which today exists only inside the DFU anti-rollback module and has not been lifted into a shared helper. TODO(shared fault-tolerant extra-MRAM probe helper + per-device config record reader): bind store.read / store.write once that lands, at which point a provisioned unit resolves from its own record instead of trusting whatever the controller board happens to hold.

Until then this app resolves from the controller's persisted value, which is what makes a vendor-provisioned driver board work out of the box, and refuses to drive anything that cannot supply one.

Returns: true when a VCOM was resolved, programmed and verified.

Return values

true	Refresh is permitted.
false	No trusted VCOM; the caller must leave the panel dark.

Precondition: display_init succeeded, so ra8_epaper_init has run.; The SPI bus seam is bound.

Postcondition: On true the controller reports the resolved VCOM.; On false no display command has been issued.

Note: Not thread-safe; boot-path use only.

Since: 0.1.0

Definition at line 612 of file main.c.

References ep_vcom_get(), ep_vcom_set(), k_ep_vcom_max_mv, k_ep_vcom_min_mv, k_ra8_ok, ra8_epd_cal_apply(), and ra8_epd_cal_resolve().

Referenced by main().

◆ ep_checker_px()

uint16_t ep_checker_px	(	uint16_t	x,
		uint16_t	y )

static

Checkerboard colour for a framebuffer pixel.

black when ((x/cell) + (y/cell)) is odd, else white – a classic e-ink alignment pattern.

Parameters

[in]	x	Column (0 .. k_ep_panel_w-1).
[in]	y	Row (0 .. k_ep_panel_h-1).

Returns: RGB565 colour for (x, y).

Return values

k_ep_black	Odd cell.
k_ep_white	Even cell.

Precondition: x < k_ep_panel_w.; y < k_ep_panel_h.

Postcondition: No state mutated.; Return depends solely on (x, y).

Note: Pure function; thread-safe.

Since: 0.1.0

Definition at line 273 of file main.c.

References k_ep_black, k_ep_cell, and k_ep_white.

Referenced by ep_paint_checker().

◆ ep_emit()

void ep_emit	(	const uint8_t *	data,
		uint32_t	len )

static

Emit a NUL-free byte span on the SCI console (best effort).

Parameters

[in]	data	Bytes to write.
[in]	len	Byte count.

Precondition: ra8_board_uart_console_init succeeded.; data != NULL.

Postcondition: len bytes have been queued to the console.; No app state mutated.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 411 of file main.c.

References ra8_board_uart_console_write().

Referenced by ep_report_init(), ep_report_stage(), and main().

◆ ep_flush_ok()

bool ep_flush_ok	(	ra8_err_t	init_err,
		ra8_err_t	full_err,
		ra8_err_t	part_err )

static

PASS verdict: every stage returned k_ra8_ok.

Parameters

[in]	init_err	display_init result.
[in]	full_err	full-refresh display_flush result.
[in]	part_err	partial-refresh display_flush result.

Returns: true iff all three stages succeeded.

Return values

true	All three are k_ra8_ok.
false	Any stage failed.

Precondition: None.; None.

Postcondition: No state mutated.; Return depends solely on the inputs.

Note: Pure function; thread-safe.

Since: 0.1.0

Definition at line 332 of file main.c.

References k_ra8_ok.

Referenced by main().

◆ ep_paint_checker()

void ep_paint_checker ( void )

static

Paint the whole framebuffer with the checkerboard pattern.

Precondition: display_get_framebuffer populated s_fb.; s_fb.pixels is reachable.

Postcondition: Every framebuffer pixel holds its checker colour.; No other state mutated.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 640 of file main.c.

References ep_checker_px(), and s_fb.

Referenced by ep_run_refresh_cycle().

◆ ep_paint_region_black()

void ep_paint_region_black ( void )

static

Blacken the partial-refresh sub-rectangle in the framebuffer.

Precondition: display_get_framebuffer populated s_fb.; The region fits inside the framebuffer.

Postcondition: Every pixel of the region is k_ep_black.; Pixels outside the region are untouched.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 662 of file main.c.

References k_ep_black, k_ep_box_h, k_ep_box_w, k_ep_box_x, k_ep_box_y, and s_fb.

Referenced by ep_run_refresh_cycle().

◆ ep_panic_halt()

void ep_panic_halt ( void )

static

Halt forever with the red board LED on.

Precondition: None.; None.

Postcondition: Function never returns; CPU parked in WFI.; Red LED is on.

Note: IRQ-safe (no shared state mutated after entry).

Since: 0.1.0

Definition at line 389 of file main.c.

References k_ra8_board_led_red, and ra8_board_led_on().

Referenced by ep_bringup_core(), ep_bringup_panel_bus(), ep_parse_or_halt(), ep_setup_or_halt(), and main().

◆ ep_region_fits()

bool ep_region_fits	(	uint16_t	x,
		uint16_t	y,
		uint16_t	w,
		uint16_t	h,
		uint16_t	pw,
		uint16_t	ph )

static

Whether a rectangle (w, h >= 1) fits wholly inside the panel.

Compound bounds guard used before the partial flush so a bad region is rejected rather than clipped. The right / bottom edge checks subsume the left / top ones for a non-empty rectangle, so the decision is the two INDEPENDENT edge tests – one on the x axis, one on the y axis.

Parameters

[in]	x	Rectangle left edge.
[in]	y	Rectangle top edge.
[in]	w	Rectangle width (>= 1).
[in]	h	Rectangle height (>= 1).
[in]	pw	Panel width.
[in]	ph	Panel height.

Returns: true iff the rectangle is fully on-panel.

Return values

true	Both the right and bottom edges are in range.
false	Either edge steps out of bounds.

Precondition: None.; None.

Postcondition: No state mutated.; Return depends solely on the inputs.

Note: Pure function; thread-safe.

Since: 0.1.0

Definition at line 308 of file main.c.

Referenced by ep_run_refresh_cycle().

◆ ep_report_init()

void ep_report_init ( void )

static

Print epaper: init ok panel=<w>x<h>.

Precondition: display_init succeeded.; ra8_board_uart_console_init succeeded.

Postcondition: One line queued to the console.; No app state mutated.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 727 of file main.c.

References ep_emit(), ep_u32_to_dec(), k_ep_cr, k_ep_lf, k_ep_line_max, k_ep_panel_h, and k_ep_panel_w.

Referenced by main().

◆ ep_report_stage()

void ep_report_stage	(	const char *	label,
		uint32_t	dt_ms,
		uint32_t	pixels )

static

Print epaper: <label> ms=<dt> px=<count> on the console.

Parameters

[in]	label	NUL-terminated stage label (e.g. "full-refresh").
[in]	dt_ms	Measured flush time in milliseconds.
[in]	pixels	Pixels refreshed this stage.

Precondition: label != NULL.; ra8_board_uart_console_init succeeded.

Postcondition: One formatted line has been queued to the console.; No app state mutated.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 690 of file main.c.

References ep_emit(), ep_u32_to_dec(), k_ep_cr, k_ep_lf, and k_ep_line_max.

Referenced by ep_run_refresh_cycle().

◆ ep_run_refresh_cycle()

void ep_run_refresh_cycle	(	ra8_err_t *	full_err,
		ra8_err_t *	part_err )

static

Drive the full (checker/GC16) then partial (box/A2) refresh cycle.

Repaints the framebuffer and flushes it twice through the display PAL: a full-panel quality refresh, then a bounds-checked partial fast refresh of the demo box. Each stage's flush time and pixel count are reported. The partial stage is skipped – leaving part_err at k_ra8_err_invalid_arg – when the box does not fit the panel.

Parameters

[out]	full_err	Receives the full-refresh flush result.
[out]	part_err	Receives the partial-refresh flush result, or k_ra8_err_invalid_arg when the box was out of bounds.

Precondition: full_err != NULL and part_err != NULL.; display_init succeeded and s_display is valid.

Postcondition: *full_err and *part_err hold this cycle's flush results.; The panel has been refreshed at least once.

Note: Not thread-safe; single-caller boot context.

Since: 0.1.0

Definition at line 765 of file main.c.

References display_flush(), display_full_rect(), ep_paint_checker(), ep_paint_region_black(), ep_region_fits(), ep_report_stage(), k_display_refresh_fast, k_display_refresh_quality, k_ep_box_h, k_ep_box_w, k_ep_box_x, k_ep_box_y, k_ep_panel_h, k_ep_panel_w, k_ra8_err_invalid_arg, ra8_now_ms(), and s_display.

Referenced by main().

◆ ep_u32_to_dec()

uint32_t ep_u32_to_dec	(	uint8_t *	buf,
		uint32_t	val )

static

Write the decimal digits of val into buf; return the count.

Parameters

[out]	buf	Destination (>= k_ep_dec_digits bytes).
[in]	val	Value to render.

Returns: Number of digit bytes written (1 .. k_ep_dec_digits).

Return values

1	For val == 0.

Precondition: buf != NULL.; buf has room for k_ep_dec_digits bytes.

Postcondition: buf[0..n-1] hold the decimal digits.; No other state mutated.

Note: Pure aside from writing buf.

Since: 0.1.0

Definition at line 354 of file main.c.

References k_ep_dec_digits, and k_ep_radix.

Referenced by ep_report_init(), and ep_report_stage().

◆ ep_vcom_get()

ra8_err_t ep_vcom_get	(	void *	ctx,
		uint16_t *	out_mv )

static

ra8_epd_cal read seam bound to the IT8951 VCOM command.

Adapts the driver's context-free signature onto the seam's (ctx, out) shape. ctx is unused: the driver keeps one panel per build.

Parameters

[in]	ctx	Unused seam context.
[out]	out_mv	Receives the controller's VCOM magnitude; non-NULL.

Returns: ra8_err_t Forwarded from ra8_epaper_get_vcom.

Return values

k_ra8_ok	Controller answered.
k_ra8_err_null_ptr	out_mv is NULL.

Precondition: ra8_epaper_init succeeded.; out_mv is writable.

Postcondition: No panel pixels are disturbed.; ctx is untouched.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 541 of file main.c.

References ra8_epaper_get_vcom().

Referenced by ep_calibrate_vcom().

◆ ep_vcom_set()

ra8_err_t ep_vcom_set	(	void *	ctx,
		uint16_t	mv )

static

ra8_epd_cal write seam bound to the IT8951 VCOM command.

The driver's ra8_epaper_set_vcom verifies its own write by reading it back, so a k_ra8_ok from here means the controller confirmed the value – not merely that bytes were clocked out.

Parameters

[in]	ctx	Unused seam context.
[in]	mv	VCOM magnitude to programme, millivolts.

Returns: ra8_err_t Forwarded from ra8_epaper_set_vcom.

Return values

k_ra8_ok	Programmed and verified.
k_ra8_err_validation_failed	Readback disagreed.

Precondition: ra8_epaper_init succeeded.; mv was range-checked by ra8_epd_cal.

Postcondition: On success the controller reports mv.; ctx is untouched.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 570 of file main.c.

References ra8_epaper_set_vcom().

Referenced by ep_calibrate_vcom().

◆ main()

void main ( void )

Application entry: e-ink full + partial refresh through the PAL.

The application entry point Reset_Handler hands control to.

Precondition: Reset_Handler copied .data and zeroed .bss.; SystemInit set VTOR / FPU / priority grouping.

Postcondition: On success the CPU heartbeats after epaper: PASS.; On any HAL error the console prints epaper: FAIL and the red LED latches on.

Since: 0.1.0

Definition at line 809 of file main.c.

References display_deinit(), display_get_caps(), display_get_framebuffer(), display_init(), ep_bringup_core(), ep_bringup_panel_bus(), ep_calibrate_vcom(), ep_emit(), ep_flush_ok(), ep_panic_halt(), ep_report_init(), ep_run_refresh_cycle(), k_display_backend_eink_it8951, k_display_pixfmt_rgb565, k_ep_heartbeat_ms, k_ep_msg_fail, k_ep_msg_no_vcom, k_ep_msg_pass, k_ep_panel_h, k_ep_panel_w, k_ep_powerup_ms, k_ra8_board_led_blue, k_ra8_err_invalid_arg, k_ra8_ok, ra8_board_led_toggle(), ra8_delay_ms(), ra8_isr_globals_enable(), s_caps, s_display, s_epaper_cfg, s_fb, and s_framebuffer.

Variable Documentation

◆ k_ep_msg_fail

const uint8_t k_ep_msg_fail[] = "epaper: FAIL\r\n"

static

Definition at line 207 of file main.c.

Referenced by main().

◆ k_ep_msg_no_vcom

const uint8_t k_ep_msg_no_vcom[] = "epaper: NO TRUSTED VCOM -- panel left dark\r\n"

static

Banner for the INV-VCOM-1 refusal.

Deliberately distinct from the generic FAIL banner: "this panel has no trusted calibration" is a different fault from "the SPI bring-up broke", and the operator's next action differs (read the number off the flex cable and provision it, versus check the wiring).

Note: Read-only.

Since: 0.1.0

Definition at line 222 of file main.c.

Referenced by main().

◆ k_ep_msg_pass

const uint8_t k_ep_msg_pass[] = "epaper: PASS\r\n"

static

PASS / FAIL banners.

Definition at line 206 of file main.c.

Referenced by main().

◆ s_caps

display_caps_t s_caps

static

Cached backend caps + framebuffer descriptor.

Definition at line 202 of file main.c.

Referenced by app_bringup_display(), and main().

◆ s_display

display_handle_t* s_display = nullptr

static

PAL handle returned by display_init.

Definition at line 199 of file main.c.

◆ s_epaper_cfg

ra8_epaper_cfg_t s_epaper_cfg

static

IT8951 descriptor handed to the e-ink backend via panel_timing.

Filled in ep_bringup_panel_bus; carries the injected SPI seam, the reset / busy GPIOs and the native panel size.

Note: File-scope so it out-lives display_init.

Since: 0.1.0

Definition at line 196 of file main.c.

Referenced by ep_bringup_panel_bus(), and main().

◆ s_fb

◆ s_framebuffer

uint16_t s_framebuffer[(uint32_t) k_ep_panel_w *(uint32_t) k_ep_panel_h]

static

RGB565 framebuffer in SRAM, 64-byte AXI-burst aligned.

The PAL hands this pointer to the e-ink backend, which converts each flushed rectangle to 8bpp greyscale on the way to the IT8951.

Note: App-owned; only this file writes it.

Since: 0.1.0

Definition at line 172 of file main.c.

◆ s_spi_bus

ra8_io_spi_bus_t s_spi_bus

static

ra8_io SPI-bus handle bound to SPI_B channel 0.

Out-lives every ra8_epaper call: the epaper bus seam's ctx points at this handle.

Note: File-scope so it survives past init.

Since: 0.1.0

Definition at line 184 of file main.c.

Referenced by ep_bringup_panel_bus().

Enumerations

Functions

Variables

Detailed Description

Hardware / off-target

Enumeration Type Documentation

◆ ep_bus_t

◆ ep_color_t

◆ ep_fmt_t

◆ ep_geom_t

◆ ep_pin_t

◆ ep_region_t

◆ ep_vcom_limits_t

Function Documentation

◆ ep_bringup_core()

◆ ep_bringup_panel_bus()

◆ ep_calibrate_vcom()

◆ ep_checker_px()

◆ ep_emit()

◆ ep_flush_ok()

◆ ep_paint_checker()

◆ ep_paint_region_black()

◆ ep_panic_halt()

◆ ep_region_fits()

◆ ep_report_init()

◆ ep_report_stage()

◆ ep_run_refresh_cycle()

◆ ep_u32_to_dec()

◆ ep_vcom_get()

◆ ep_vcom_set()

◆ main()

Variable Documentation

◆ k_ep_msg_fail

◆ k_ep_msg_no_vcom

◆ k_ep_msg_pass

◆ s_caps

◆ s_display

◆ s_epaper_cfg

◆ s_fb

◆ s_framebuffer

◆ s_spi_bus