Event Link Controller driver. More...

#include <stdint.h>
#include "ra8_elc_regs.h"
#include "ra8_err.h"

Include dependency graph for ra8_elc.h:

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

Enumerations
enum	ra8_elc_dim_t : uint8_t { k_ra8_elc_elsr_count = 53U , k_ra8_elc_segr_count = 4U }
	ELC register-array dimensions. More...

Functions
ra8_err_t	ra8_elc_init (void)
	Reset the ELC register block and enable the controller.
ra8_err_t	ra8_elc_deinit (void)
	Disable the ELC globally (ELCR.ELCON = 0) and stop the module.
ra8_err_t	ra8_elc_link (uint8_t elsr_index, ra8_elc_event_t event)
	Route an ELC event to an ELSR slot so the destination peripheral triggers on it.
ra8_err_t	ra8_elc_unlink (uint8_t elsr_index)
	Clear one ELSR slot so it stops routing any event.
ra8_err_t	ra8_elc_software_trigger (uint8_t event_index)
	Fire a software event via one of the ELSEGRn registers.
ra8_err_t	ra8_elc_is_enabled (bool *out_enabled)
	Read ELCR.ELCON to verify the global enable state.

Detailed Description

Event Link Controller driver.

Tag: [Ring 3 / HAL] {World: S}

Owns every write to the ELC register block (ELCR, ELSEGR0..3, ELSR0..52, ELCSAR{A,B,C}, ELCPAR{A,B,C}) at 0x40201000 (HUM Ch 19, p 817..836). Layout cross-verified against FSP R_ELC_Type in R7KA8D2KF_core0.h.

The ELC lets one peripheral's event directly trigger another peripheral's input without CPU involvement. The driver exposes the following operation-named helpers:

ra8_elc_init – reset ELSR array, enable ELC.
ra8_elc_deinit – disable ELC globally.
ra8_elc_link – route event -> ELSR slot.
ra8_elc_unlink – clear one ELSR slot.
ra8_elc_software_trigger – fire a software event using the 3-step ELSEGR unlock-and-set sequence (HUM Ch 19.2.2).
ra8_elc_is_enabled – diagnostic accessor.

Drivers call these helpers; they never touch the ELC registers directly. The NSC veneer surface is ra8_elc_*.

ELSR index range

HUM Ch 19.2.3 (p 817) / FSP R_ELC_Type assign 53 ELSR slots (ELSR0..ELSR52), each a 16-bit register at a 4-byte stride that stores one ELC event number (the ELS field is 10 bits wide). The mapping of slot to destination peripheral is fixed and lives in HUM Table 19.2; callers learn it from the peripheral datasheets.

Threading

Single-threaded init context only.

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

Definition in file ra8_elc.h.

Enumeration Type Documentation

◆ ra8_elc_dim_t

enum ra8_elc_dim_t : uint8_t

ELC register-array dimensions.

Enumerator
k_ra8_elc_elsr_count	ELSR0..ELSR52 (FSP R_ELC_Type).
k_ra8_elc_segr_count	ELSEGR0..ELSEGR3 (FSP R_ELC_Type).

Definition at line 61 of file ra8_elc.h.

Function Documentation

◆ ra8_elc_deinit()

ra8_err_t ra8_elc_deinit ( void )

nodiscard

Disable the ELC globally (ELCR.ELCON = 0) and stop the module.

Returns: k_ra8_ok.

Precondition: IRQs masked or single-threaded init context.; ra8_elc_init was called previously.

Postcondition: ELCR.ELCON == 0.; MSTPCRC ELC bit is set (module stopped).

Note: Thread safety: not thread-safe.

Since: 0.1.0

Definition at line 120 of file ra8_elc.c.

References internal_elcr(), k_ra8_mstp_elc, and ra8_mstp_disable().

◆ ra8_elc_init()

ra8_err_t ra8_elc_init ( void )

nodiscard

Reset the ELC register block and enable the controller.

Powers the ELC module via MSTPCRC, clears every ELSR slot (ELSR0..ELSR52), clears ELSEGR0..3, then sets ELCR.ELCON = 1 so the hardware routes events.

Returns: k_ra8_ok.

Precondition: Caller is in single-threaded init context.; IRQs masked or single-threaded init context.

Postcondition: ELSR0..ELSR52 == 0.; ELCR.ELCON == 1 (controller enabled).

Note: Thread safety: not thread-safe.

Since: 0.1.0

Definition at line 91 of file ra8_elc.c.

References internal_elcr(), internal_elsegr(), internal_elsr(), k_ra8_elc_elsegr_step_unlock, k_ra8_elc_elsr_count, k_ra8_elc_segr_count, k_ra8_elcr_bit_elcon, k_ra8_mstp_elc, k_ra8_ok, ra8_log_info, ra8_mstp_enable(), RA8_RETURN_ON_ERROR, and s_tag.

Referenced by dtc_arm_setup_or_halt(), dtc_coh_setup_or_halt(), dtc_demo_setup_or_halt(), and internal_setup_or_halt().

◆ ra8_elc_is_enabled()

ra8_err_t ra8_elc_is_enabled ( bool * out_enabled )

nodiscard

Read ELCR.ELCON to verify the global enable state.

Parameters

[out] out_enabled On success, true if ELCON is set.

Returns: ra8_err_t error code.

Return values

k_ra8_ok	Value returned.
k_ra8_err_null_ptr	out_enabled was NULL.

Precondition: out_enabled is non-NULL.

Postcondition: No hardware state is modified.

Since: 0.1.0

Definition at line 164 of file ra8_elc.c.

References internal_elcr(), k_ra8_elcr_bit_elcon, k_ra8_ok, RA8_CHECK_NULL_PTR, and s_tag.

Referenced by main().

◆ ra8_elc_link()

ra8_err_t ra8_elc_link	(	uint8_t	elsr_index,
		ra8_elc_event_t	event )

nodiscard

Route an ELC event to an ELSR slot so the destination peripheral triggers on it.

Parameters

[in]	elsr_index	Slot number 0..k_ra8_elc_elsr_count - 1.
[in]	event	ELC event number from ra8_elc_event_t.

Returns: ra8_err_t error code.

Return values

k_ra8_ok	Slot programmed.
k_ra8_err_out_of_range	elsr_index out of range.

Precondition: IRQs masked or single-threaded init context.

Postcondition: ELSR[elsr_index] holds event.

Note: Thread safety: not thread-safe.

Since: 0.1.0

Definition at line 127 of file ra8_elc.c.

References internal_elsr(), k_ra8_elc_elsr_count, k_ra8_err_out_of_range, and k_ra8_ok.

Referenced by internal_setup_or_halt().

◆ ra8_elc_software_trigger()

ra8_err_t ra8_elc_software_trigger ( uint8_t event_index )

nodiscard

Fire a software event via one of the ELSEGRn registers.

Per HUM Ch 19.2.2 "ELSEGRn : Event Link Software Event Generation Register n" (p 817) and FSP R_ELC_SoftwareEventGenerate, the SEG bit is write-protected by WI/WE and must be set with a three-step sequence:

Write 0x00 (k_ra8_elc_elsegr_step_unlock) – clear WI.
Write 0x40 (k_ra8_elc_elsegr_step_arm) – set WE, SEG=0.
Write 0x41 (k_ra8_elc_elsegr_step_trigger) – set SEG=1.

The hardware fires the event exactly once. Useful for testing event-driven paths without waiting for a real peripheral edge.

Parameters

[in] event_index Software event 0..3 (selects ELSEGR0..3).

Returns: ra8_err_t error code.

Return values

k_ra8_ok	Three-step sequence written.
k_ra8_err_invalid_arg	event_index out of range.

Precondition: IRQs masked or single-threaded init context.; ELC is enabled via ra8_elc_init.

Postcondition: ELSEGR[event_index] holds 0x41 after the call returns; the event fires once on the next ELC clock edge.

Note: Thread safety: not thread-safe.

Since: 0.1.0

Definition at line 147 of file ra8_elc.c.

References internal_elsegr(), k_ra8_elc_elsegr_step_arm, k_ra8_elc_elsegr_step_trigger, k_ra8_elc_elsegr_step_unlock, k_ra8_elc_segr_count, k_ra8_err_invalid_arg, and k_ra8_ok.

Referenced by dtc_arm_run_armed(), dtc_arm_run_disarmed(), dtc_coh_run_once(), dtc_demo_run_once(), and main().

◆ ra8_elc_unlink()

ra8_err_t ra8_elc_unlink ( uint8_t elsr_index )

nodiscard

Clear one ELSR slot so it stops routing any event.

Parameters

[in] elsr_index Slot number 0..k_ra8_elc_elsr_count - 1.

Returns: ra8_err_t error code.

Return values

k_ra8_ok	Slot cleared.
k_ra8_err_out_of_range	elsr_index out of range.

Precondition: IRQs masked or single-threaded init context.

Postcondition: ELSR[elsr_index] == 0.

Note: Thread safety: not thread-safe.

Since: 0.1.0

Definition at line 137 of file ra8_elc.c.

References internal_elsr(), k_ra8_elc_elsr_count, k_ra8_err_out_of_range, and k_ra8_ok.

Enumerations

Functions

Detailed Description

ELSR index range

Threading

Enumeration Type Documentation

◆ ra8_elc_dim_t

Function Documentation

◆ ra8_elc_deinit()

◆ ra8_elc_init()

◆ ra8_elc_is_enabled()

◆ ra8_elc_link()

◆ ra8_elc_software_trigger()

◆ ra8_elc_unlink()