HAL SysTick + DWT timebase demo for EK-RA8D2 (SCI8 @ 115200). More...

#include <stddef.h>
#include <stdint.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_systick.h"
#include "ra8_time.h"

Include dependency graph for main.c:

Enumerations
enum	hal_timebase_config_t : uint32_t { k_demo_baud = 115200U , k_demo_period_ms = 1000U , k_demo_tick_hz = 1000U , k_demo_u32_digits = 10U , k_demo_hz_per_mhz = 1000000U , k_demo_dec_base = 10U }
	Compile-time settings for the demo. More...

Functions
static void	demo_panic_halt (void)
	Halt forever in WFI – used as a panic stop on init failure.
static void	demo_emit (const uint8_t *data, size_t len)
	Write a byte span to the SCI8 console, ignoring flow-control errors.
static void	demo_emit_u32 (uint32_t value)
	Emit a uint32_t as decimal ASCII over the console.
static ra8_err_t	demo_setup_or_halt (uint32_t *out_cpuclk_hz)
	Bring up CGC + raw ra8_time + console + LED + the HAL timebase.
static void	demo_emit_measurement (uint32_t cpuclk_hz)
	Emit one measurement line: DWT-timed length of a 1 s delay.
void	main (void)
	Application entry.

Variables
static const uint8_t	k_demo_lbl_reload [] = "reload="
	Label emitted once with the HAL-computed SysTick reload.
static const uint8_t	k_demo_lbl_ms [] = "hal timebase ms="
	Label opening each per-second measurement line.
static const uint8_t	k_demo_lbl_cycles [] = " cycles="
	Field separator before the DWT cycle count.
static const uint8_t	k_demo_lbl_us [] = " us="
	Field separator before the derived microseconds.
static const uint8_t	k_demo_crlf [] = "\r\n"
	Line terminator.

Detailed Description

HAL SysTick + DWT timebase demo for EK-RA8D2 (SCI8 @ 115200).

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

Exercises the ra8_core SysTick / DWT timebase primitive (ra8_systick_reload_for, ra8_systick_configure, ra8_systick_current_value, ra8_dwt_cyccnt_enable / ra8_dwt_cyccnt_reset / ra8_dwt_cyccnt_read) on real silicon, ALONGSIDE the existing raw-poke ra8_time path, so the two can be diffed on the bench (issue #582). Both program the same architectural SysTick registers; this app shows the HAL primitive producing the identical reload the raw path uses, and uses the DWT cycle counter to measure the wall-clock length of an ra8_delay_ms() produced by the raw path.

Sequence:

ra8_cgc_init() – XTAL + PLL1 up, CPUCLK0 = 1 GHz, PCLKA = 125 MHz.
ra8_cgc_get_clock_hz(k_ra8_clock_id_cpuclk0, ...) – the live core clock.
ra8_time_init(cpuclk0_hz) – the raw-poke path arms SysTick + DWT and backs ra8_delay_ms().
ra8_board_uart_console_init(115200) – SCI8 J-Link OB console.
ra8_dwt_cyccnt_enable() – the HAL primitive owns the DWT enable.
ra8_systick_reload_for(cpuclk0_hz, 1000, &reload) – HAL arithmetic; print the reload so it can be compared against SYST_RVR on the bench.
ra8_systick_configure(reload, k_ra8_systick_clk_cpu, true) – the HAL path arms the same SysTick the raw path did (same reload, same control bits), so ra8_delay_ms() keeps working.
Loop: reset DWT, ra8_delay_ms(1000), read DWT -> print the measured cycles and derived microseconds, and toggle LED1 as a heartbeat.

Verification: open the J-Link OB CDC port at 115200 8N1. You should see a reload=999999 line once, then a hal timebase ms=1000 cycles=<n> us=<n> line per second with LED1 toggling in lock-step. On a 1 GHz core the measured microseconds land near 1000000 for a 1000 ms delay.

Author: Brighton Sikarskie

Date: 2026-08-02

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

Since: 0.1.0

Definition in file main.c.

Enumeration Type Documentation

◆ hal_timebase_config_t

enum hal_timebase_config_t : uint32_t

Compile-time settings for the demo.

Enumerator
k_demo_baud	Console baud.
k_demo_period_ms	Heartbeat + measured-delay period.
k_demo_tick_hz	1 kHz -> 1 ms SysTick tick.
k_demo_u32_digits	Max decimal digits in a uint32_t.
k_demo_hz_per_mhz	Hz per MHz -> cycles-per-us divisor.
k_demo_dec_base	Decimal radix for the number emitter.

Definition at line 58 of file main.c.

Function Documentation

◆ demo_emit()

void demo_emit	(	const uint8_t *	data,
		size_t	len )

static

Write a byte span to the SCI8 console, ignoring flow-control errors.

Thin wrapper over the board console so the callers below read as a sequence of field emissions. A transient console error is non-fatal for a demo, so the return is intentionally discarded.

Parameters

[in]	data	Pointer to the bytes to emit. Must be non-NULL.
[in]	len	Number of bytes to emit. Zero is a no-op.

Precondition: data points to at least len readable bytes.; The console has been initialised.

Postcondition: len bytes have been queued to the console (best effort).; No application state is modified.

Note: Not thread-safe; called only from the single-threaded main loop.

Since: 0.1.0

Definition at line 118 of file main.c.

References ra8_board_uart_console_write().

Referenced by demo_emit_measurement(), demo_emit_u32(), and demo_setup_or_halt().

◆ demo_emit_measurement()

void demo_emit_measurement ( uint32_t cpuclk_hz )

static

Emit one measurement line: DWT-timed length of a 1 s delay.

Zeroes the DWT counter, runs ra8_delay_ms(k_demo_period_ms) (the raw path), samples the elapsed cycles, and derives microseconds as cycles / (cpuclk_hz / 1e6). The divisor is floored at one so a sub-MHz clock cannot divide by zero.

Parameters

[in] cpuclk_hz Live CPUCLK0 in Hz, used to convert cycles to us.

Precondition: The DWT cycle counter is enabled and the console is up.; cpuclk_hz is the clock ra8_delay_ms() was calibrated against.

Postcondition: One hal timebase ... line has been emitted.; The DWT counter has been zeroed and has resumed counting.

Note: Not thread-safe; called only from the single-threaded main loop.

Since: 0.1.0

Definition at line 249 of file main.c.

References demo_emit(), demo_emit_u32(), k_demo_crlf, k_demo_hz_per_mhz, k_demo_lbl_cycles, k_demo_lbl_ms, k_demo_lbl_us, k_demo_period_ms, ra8_delay_ms(), ra8_dwt_cyccnt_read(), and ra8_dwt_cyccnt_reset().

Referenced by main().

◆ demo_emit_u32()

void demo_emit_u32 ( uint32_t value )

static

Emit a uint32_t as decimal ASCII over the console.

Formats value into a fixed 10-byte scratch buffer from the least significant digit up, then emits the significant span. Uses only single-condition, statically bounded loops (at most 10 iterations) so it carries no compound decision and no unbounded loop.

Parameters

[in] value Value to print in base ten.

Precondition: The console has been initialised.; None beyond the above.

Postcondition: The decimal text of value has been queued to the console.; No application state is modified.

Note: Not thread-safe; called only from the single-threaded main loop.

Since: 0.1.0

Definition at line 141 of file main.c.

References demo_emit(), k_demo_dec_base, and k_demo_u32_digits.

Referenced by demo_emit_measurement(), and demo_setup_or_halt().

◆ demo_panic_halt()

void demo_panic_halt ( void )

static

Halt forever in WFI – used as a panic stop on init failure.

Parks the core so a boot failure is a visible dead LED / silent console rather than undefined execution. Only a debugger or an external reset resumes it.

Precondition: Called only after a fatal error during boot.; The console may or may not be up; no output is attempted here.

Postcondition: The CPU is parked in a WFI spin.; No further application code runs.

Note: Never returns.

Since: 0.1.0

Definition at line 93 of file main.c.

Referenced by demo_fs_format_or_panic(), demo_lx_format_or_panic(), demo_lx_open_or_panic(), demo_setup_or_halt(), demo_setup_or_halt(), and main().

◆ demo_setup_or_halt()

ra8_err_t demo_setup_or_halt ( uint32_t * out_cpuclk_hz )

static

Bring up CGC + raw ra8_time + console + LED + the HAL timebase.

Runs the raw ra8_time_init() path first (it arms SysTick + DWT and backs ra8_delay_ms()), then re-arms the SAME SysTick through the HAL primitive with the reload the HAL arithmetic derives – demonstrating the primitive substitutes for the raw poke with no timing change. Panic-halts on any failure. On success the HAL-computed reload has been emitted once.

Parameters

[out] out_cpuclk_hz Receives the live CPUCLK0 frequency in Hz.

Returns: Error code.

Return values

k_ra8_ok	Everything up; *out_cpuclk_hz is valid.
k_ra8_err_invalid_arg	out_cpuclk_hz is NULL.

Precondition: out_cpuclk_hz is a valid, writable uint32_t.; Reset_Handler and SystemInit have completed.

Postcondition: On success SysTick + DWT are running and the console is up.; On any HAL failure the function does not return (panic-halt).

Note: Not thread-safe; one-shot boot helper.

Since: 0.1.0

Definition at line 187 of file main.c.

References demo_emit(), demo_emit_u32(), demo_panic_halt(), k_demo_baud, k_demo_crlf, k_demo_lbl_reload, k_demo_tick_hz, k_ra8_board_led1, k_ra8_clock_id_cpuclk0, k_ra8_err_invalid_arg, k_ra8_ok, k_ra8_systick_clk_cpu, ra8_board_led_init(), ra8_board_uart_console_init(), ra8_cgc_get_clock_hz(), ra8_cgc_init(), ra8_dwt_cyccnt_enable(), ra8_systick_configure(), ra8_systick_reload_for(), and ra8_time_init().

◆ main()

void main ( void )

Application entry.

The application entry point Reset_Handler hands control to.

Brings up the timebase then measures forever.

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

Postcondition: On clean entry the CPU stays in the measure + blink loop forever.; On any HAL init failure the function halts in WFI.

Note: Never returns.

Since: 0.1.0

Definition at line 281 of file main.c.

References demo_emit_measurement(), demo_panic_halt(), demo_setup_or_halt(), k_ra8_board_led1, k_ra8_ok, ra8_board_led_toggle(), and ra8_isr_globals_enable().

Variable Documentation

◆ k_demo_crlf

const uint8_t k_demo_crlf[] = "\r\n"

static

Line terminator.

Definition at line 76 of file main.c.

Referenced by demo_emit_measurement(), and demo_setup_or_halt().

◆ k_demo_lbl_cycles

const uint8_t k_demo_lbl_cycles[] = " cycles="

static

Field separator before the DWT cycle count.

Definition at line 72 of file main.c.

Referenced by demo_emit_measurement().

◆ k_demo_lbl_ms

const uint8_t k_demo_lbl_ms[] = "hal timebase ms="

static

Label opening each per-second measurement line.

Definition at line 70 of file main.c.

Referenced by demo_emit_measurement().

◆ k_demo_lbl_reload

const uint8_t k_demo_lbl_reload[] = "reload="

static

Label emitted once with the HAL-computed SysTick reload.

Definition at line 68 of file main.c.

Referenced by demo_setup_or_halt().

◆ k_demo_lbl_us

const uint8_t k_demo_lbl_us[] = " us="

static

Field separator before the derived microseconds.

Definition at line 74 of file main.c.

Referenced by demo_emit_measurement().

Enumerations

Functions

Variables

Detailed Description

Enumeration Type Documentation

◆ hal_timebase_config_t

Function Documentation

◆ demo_emit()

◆ demo_emit_measurement()

◆ demo_emit_u32()

◆ demo_panic_halt()

◆ demo_setup_or_halt()

◆ main()

Variable Documentation

◆ k_demo_crlf

◆ k_demo_lbl_cycles

◆ k_demo_lbl_ms

◆ k_demo_lbl_reload

◆ k_demo_lbl_us