main.c File Reference

IWDT window-mode refresh demo for EK-RA8D2. More...

#include <stdint.h>
#include "ra8_attributes.h"
#include "ra8_board_ek_ra8d2.h"
#include "ra8_boot_entry.h"
#include "ra8_cgc.h"
#include "ra8_err.h"
#include "ra8_isr.h"
#include "ra8_iwdt.h"
#include "ra8_time.h"

Include dependency graph for main.c:

Go to the source code of this file.

Enumerations
enum	iwdt_demo_const_t : uint32_t {   k_iwdt_demo_baud = 115200U ,   k_iwdt_demo_poll_ms = 50U }
	Demo tunables. More...
enum	iwdt_demo_window_t : uint16_t {   k_iwdt_demo_window_low = 0x0400U ,   k_iwdt_demo_window_high = 0x0C00U }
	Window bounds in 14-bit IWDTSR.CNTVAL units (HUM 28.2.2). More...

Functions
static void	internal_panic_halt (void)
	Park the core after an unrecoverable IWDT demo failure.
static void	internal_setup_or_halt (void)
	Initialize clocks, SysTick, SCI8, and LED1.
static bool	internal_in_window (uint16_t counter)
	Decide whether the live counter sits inside the legal window.
void	main (void)
	Poll and refresh the IWDT only inside its legal window.

Variables
static const uint8_t	s_iwdt_demo_msg_refresh [] = "iwdt: refresh in window\r\n"
static const uint8_t	s_iwdt_demo_msg_boot [] = "iwdt: poll counter\r\n"

Detailed Description

IWDT window-mode refresh demo for EK-RA8D2.

Tag

[Ring 6 / APP] {World: S}

Demonstrates the IWDT in window mode, distinct from the existing watchdog_demo which simply refreshes until it stops. The IWDT period and window-start / window-end positions are programmed in the OFS0 option-setting register at flash time – the chip cannot reconfigure them at runtime. This demo refreshes the counter only inside the legal window (between IWDTRPES and IWDTRPSS) via ra8_iwdt_refresh_deferred, observes the live counter via ra8_iwdt_get_counter, and reads the IWDTSR underflow / refresh- error status via ra8_iwdt_get_status to detect window violations.

Bring-up sequence:

1. CGC + SysTick + UART (SCI8) + LED1.
2. ra8_iwdt_init (no-op on RA8D2 – OFS0 owns the period).
3. Loop: poll counter; refresh only when the counter is inside the legal window; clear status; toggle LED1 each refresh.

Copyright

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

Since

0.1.0

Definition in file main.c.

Enumeration Type Documentation

iwdt_demo_const_t

enum iwdt_demo_const_t : uint32_t

Demo tunables.

Enumerator
k_iwdt_demo_baud	Iwdt demo baud.
k_iwdt_demo_poll_ms	Iwdt demo poll ms.

Definition at line 42 of file main.c.

iwdt_demo_window_t

enum iwdt_demo_window_t : uint16_t

Window bounds in 14-bit IWDTSR.CNTVAL units (HUM 28.2.2).

Enumerator
k_iwdt_demo_window_low	Refresh-permitted lower bound.
k_iwdt_demo_window_high	Refresh-permitted upper bound.

Definition at line 48 of file main.c.

Function Documentation

internal_in_window()

bool internal_in_window ( uint16_t counter )

static

Decide whether the live counter sits inside the legal window.

Applies the inclusive lower and upper OFS0-derived bounds used by the foreground loop before requesting a deferred refresh.

MC/DC:

Compound decision: counter >= low && counter <= high. Two atomic conditions x 3 vectors – both true (golden), low fail, high fail (test_app_iwdt_demo.c).

Parameters

[in]

counter

Current 14-bit IWDT counter sample.

Returns

Whether refreshing at this sample is permitted.

Return values

true	counter lies within both inclusive bounds.
false	counter is below the lower or above the upper bound.

Precondition

counter was sampled from the active IWDT instance.

The compiled window constants match the programmed OFS0 policy.

Postcondition

No hardware or application state is modified.

The result depends only on counter and the fixed bounds.

Note

Pure and reentrant.

Since

0.1.0

Definition at line 132 of file main.c.

References k_iwdt_demo_window_high, k_iwdt_demo_window_low, and RA8_INTERNAL.

Referenced by main().

internal_panic_halt()

void internal_panic_halt ( void )

static

Park the core after an unrecoverable IWDT demo failure.

Repeatedly executes WFI, retaining live IWDT and status-register state for an attached debugger until reset.

Precondition

Called only from the boot or terminal foreground path.

The caller does not require this function to return.

Postcondition

The core remains in the WFI loop until external intervention.

No further explicit IWDT refresh is issued.

Note

Not thread-safe; this is the terminal single-threaded path.

Since

0.1.0

Definition at line 69 of file main.c.

References RA8_INTERNAL.

internal_setup_or_halt()

void internal_setup_or_halt ( void )

static

Initialize clocks, SysTick, SCI8, and LED1.

Brings the foreground loop's dependencies up in order and transfers to the panic helper if any clock, console, or LED operation fails.

Precondition

Reset startup initialized static storage and the vector table.

Called once before global interrupt enable.

Postcondition

On return, SCI8 and LED1 are ready and delays use the CPU clock.

IWDT option-register configuration remains unchanged.

Note

Not thread-safe; it mutates global board and clock state.

Since

0.1.0

Definition at line 89 of file main.c.

References internal_panic_halt(), k_iwdt_demo_baud, k_ra8_board_led1, k_ra8_clock_id_cpuclk0, k_ra8_ok, ra8_board_led_init(), ra8_board_uart_console_init(), ra8_cgc_get_clock_hz(), ra8_cgc_init(), RA8_INTERNAL, and ra8_time_init().

main()

void main

(

void

)

Poll and refresh the IWDT only inside its legal window.

The application entry point Reset_Handler hands control to.

Emits the boot banner, initializes the option-controlled IWDT, samples its counter, and on legal samples queues a refresh, clears status, toggles LED1, and emits the refresh banner.

Precondition

Reset startup and SystemInit completed successfully.

OFS0 contains the window policy represented by the demo constants.

Postcondition

Each reported refresh was requested only within the inclusive window.

Any HAL or output error leads to the terminal panic helper.

Note

Does not return during normal operation.

Since

0.1.0

Definition at line 152 of file main.c.

References internal_in_window(), internal_panic_halt(), internal_setup_or_halt(), k_iwdt_demo_poll_ms, k_ra8_board_led1, k_ra8_ok, ra8_board_led_toggle(), ra8_board_uart_console_write(), ra8_delay_ms(), ra8_isr_globals_enable(), ra8_iwdt_clear_status(), ra8_iwdt_get_counter(), ra8_iwdt_init(), ra8_iwdt_refresh_deferred(), s_iwdt_demo_msg_boot, and s_iwdt_demo_msg_refresh.

Variable Documentation

s_iwdt_demo_msg_boot

const uint8_t s_iwdt_demo_msg_boot[] = "iwdt: poll counter\r\n"

static

Definition at line 54 of file main.c.

Referenced by main().

s_iwdt_demo_msg_refresh

const uint8_t s_iwdt_demo_msg_refresh[] = "iwdt: refresh in window\r\n"

static

Definition at line 53 of file main.c.

Referenced by main().