BSP-driven I2S audio playback demo for EK-RA8D2 (DA7212 CODEC). 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_time.h"

Include dependency graph for main.c:

Enumerations
enum	audio_loopback_config_t : uint32_t { k_audio_loopback_baud = 115200U , k_audio_loopback_print_period = 1000U , k_audio_loopback_sample_rate = 48000U }
	Compile-time settings for the BSP-driven audio playback demo. More...
enum	audio_loopback_chan_t : uint8_t { k_audio_loopback_bit_depth = 16U , k_audio_loopback_channels = 2U }
	uint8_t format ids consumed by the BSP audio path. More...
enum	audio_loopback_block_t : uint32_t { k_audio_loopback_block_samples = 128U }
	Stereo block size in interleaved L/R 16-bit samples. More...

Functions
static void	internal_audio_loopback_panic_halt (void)
	Halt forever in WFI – used as a panic stop on init failure.
static void	internal_audio_loopback_init_clocks_and_led (void)
	Bring CGC + SysTick + LED1 up.
static void	internal_audio_loopback_init_console (void)
	Open the BSP J-Link console (SCI8 @ 115200 8N1, PD02/PD03).
static void	internal_audio_loopback_init_codec (void)
	Bring the on-board DA7212 CODEC + SSIE0 up via the BSP.
static uint32_t	internal_audio_loopback_u32_to_dec (uint32_t value, uint8_t *buf)
	Convert a 32-bit unsigned integer into an ASCII decimal string.
static void	internal_audio_loopback_print_count (uint32_t block_count)
	Print "audio: <count> blocks played\\r\\n" over the BSP console.
void	main (void)
	Application entry.

Variables
static const uint8_t	s_audio_loopback_msg_prefix [] = "audio: "
	Diagnostic banner emitted every k_audio_loopback_print_period blocks.
static const uint8_t	s_audio_loopback_msg_suffix [] = " blocks played\r\n"
static const int16_t	s_audio_loopback_silence [k_audio_loopback_block_samples] = {}
	Static stereo silence buffer fed to the CODEC each iteration.

Detailed Description

BSP-driven I2S audio playback demo for EK-RA8D2 (DA7212 CODEC).

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

Brings the chip up via ra8_cgc_init() (XTAL -> PLL1 -> CPUCLK0 = 1 GHz, PCLKA = 125 MHz, SCICLK = PLL1R / 4), then hands the entire SSIE0 + DA7212 CODEC bring-up to the EK-RA8D2 BSP via ra8_board_audio_init(48000, 16, 2). The BSP routes the CODEC pins (P403/P404/P405/P406/PD06 + I2C control on P511/P512 per UM Table 32 p 38), enables SSIE0 in I2S controller mode, and exposes ra8_board_audio_play_sample_block for stereo PCM block writes.

After init the firmware loops feeding a small repeating stereo buffer to ra8_board_audio_play_sample_block, prints "audio: <N> blocks played\r\n" over the J-Link OB CDC port (SCI8 @ 115200) every k_audio_loopback_print_period blocks, and toggles LED1 once per log line.

Sequence:

ra8_cgc_init() – standard FSP-quickstart clock tree.
ra8_time_init(cpuclk0_hz) for the diagnostic-print throttle.
ra8_board_uart_console_init(115200) – BSP routes PD02 TXD / PD03 RXD and opens SCI8 @ 115200 8N1 for diagnostic output.
ra8_board_audio_init(48000, 16, 2) – BSP wires SSIE0 + CODEC pins and starts the I2S controller.
Loop: push the stereo sample block via ra8_board_audio_play_sample_block, increment counter, log every k_audio_loopback_print_period blocks.

Architectural ring: [Ring 6 / APP] {World: S} – application-layer code that runs in the Secure world.

Author: Brighton Sikarskie

Date: 2026-04-29

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

Since: 0.1.0

Definition in file main.c.

Enumeration Type Documentation

◆ audio_loopback_block_t

enum audio_loopback_block_t : uint32_t

Stereo block size in interleaved L/R 16-bit samples.

Enumerator
k_audio_loopback_block_samples	64 stereo frames * 2 ch.

Definition at line 75 of file main.c.

◆ audio_loopback_chan_t

enum audio_loopback_chan_t : uint8_t

uint8_t format ids consumed by the BSP audio path.

Enumerator
k_audio_loopback_bit_depth	Audio loopback bit depth.
k_audio_loopback_channels	Audio loopback channels.

Definition at line 69 of file main.c.

◆ audio_loopback_config_t

enum audio_loopback_config_t : uint32_t

Compile-time settings for the BSP-driven audio playback demo.

The print throttle is per-1000 blocks; at 48 kHz with 64 stereo frames per block that is one log line every ~1.3 s.

Enumerator
k_audio_loopback_baud	Audio loopback baud.
k_audio_loopback_print_period	Audio loopback print period.
k_audio_loopback_sample_rate	Audio loopback sample rate.

Definition at line 62 of file main.c.

Function Documentation

◆ internal_audio_loopback_init_clocks_and_led()

void internal_audio_loopback_init_clocks_and_led ( void )

static

Bring CGC + SysTick + LED1 up.

Halts on any fail.

Splits the long boot sequence so each step stays under the NASA Power-of-10 60-line function-size cap.

Precondition: Reset_Handler has copied .data and zeroed .bss.; Caller is single-threaded init context.

Postcondition: On success the CGC, SysTick, and LED1 are live.; Halts in WFI on init failure.

Note: Initialization is deliberately fail-stop so playback never begins with a partially configured clock or GPIO tree.

Since: 0.1.0

Definition at line 135 of file main.c.

References internal_audio_loopback_panic_halt(), k_ra8_board_led1, k_ra8_clock_id_cpuclk0, k_ra8_ok, ra8_board_led_init(), ra8_cgc_get_clock_hz(), ra8_cgc_init(), RA8_INTERNAL, and ra8_time_init().

Referenced by main().

◆ internal_audio_loopback_init_codec()

void internal_audio_loopback_init_codec ( void )

static

Bring the on-board DA7212 CODEC + SSIE0 up via the BSP.

ra8_board_audio_init routes the CODEC pins (P403/P404/P405/P406/ PD06 per UM Table 32 p 38) and brings SSIE0 up in I2S controller mode at the requested format. The application no longer touches SSIE registers directly.

Precondition: Pin mux table is unlocked (single-threaded init context).; J41 jumpers populated (CODEC selected over camera).

Postcondition: DA7212 + SSIE0 are live and ready for sample-block writes.; Halts in WFI on init failure.

Note: The BSP owns board-specific pin routing and codec control traffic.

Since: 0.1.0

Definition at line 196 of file main.c.

References internal_audio_loopback_panic_halt(), k_audio_loopback_bit_depth, k_audio_loopback_channels, k_audio_loopback_sample_rate, k_ra8_ok, ra8_board_audio_init(), and RA8_INTERNAL.

Referenced by main().

◆ internal_audio_loopback_init_console()

void internal_audio_loopback_init_console ( void )

static

Open the BSP J-Link console (SCI8 @ 115200 8N1, PD02/PD03).

Hands the SCI8 + PD02 TXD / PD03 RXD pin routing and baud setup to the EK-RA8D2 BSP via ra8_board_uart_console_init.

Precondition: Clocks have been initialized.; Caller is single-threaded init context.

Postcondition: SCI8 is enabled for diagnostic output.; Halts in WFI on init failure.

Note: Console writes remain best-effort after this routine returns.

Since: 0.1.0

Definition at line 170 of file main.c.

References internal_audio_loopback_panic_halt(), k_audio_loopback_baud, k_ra8_ok, ra8_board_uart_console_init(), and RA8_INTERNAL.

Referenced by main().

◆ internal_audio_loopback_panic_halt()

void internal_audio_loopback_panic_halt ( void )

static

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

Masks no additional interrupts; repeated WFI instructions keep the core quiescent while preserving register state for a debugger.

Precondition: Called only after a fatal error in boot.; No recovery path remains for the current boot attempt.

Postcondition: CPU is parked; only a debugger or external reset wakes it.; No peripheral state is changed after entry.

Note: This helper deliberately does not attempt logging because the console may be the peripheral whose initialization failed.

Since: 0.1.0

Definition at line 110 of file main.c.

References RA8_INTERNAL.

Referenced by internal_audio_loopback_init_clocks_and_led(), internal_audio_loopback_init_codec(), internal_audio_loopback_init_console(), and main().

◆ internal_audio_loopback_print_count()

void internal_audio_loopback_print_count ( uint32_t block_count )

static

Print "audio: <count> blocks played\\r\\n" over the BSP console.

Formats the count into a bounded stack buffer and emits the prefix, digits, and suffix as three allocation-free console writes.

Parameters

[in] block_count Cumulative block count.

Precondition: The BSP console is initialized.; block_count is the monotonic playback-loop counter snapshot.

Postcondition: Three writes have been issued on the BSP console.; No heap or dynamic allocations.

Note: Individual write failures are intentionally ignored because this is diagnostic output and must not stop audio playback.

Since: 0.1.0

< Dec buffer.

Definition at line 272 of file main.c.

References internal_audio_loopback_u32_to_dec(), ra8_board_uart_console_write(), RA8_INTERNAL, s_audio_loopback_msg_prefix, and s_audio_loopback_msg_suffix.

Referenced by main().

◆ internal_audio_loopback_u32_to_dec()

uint32_t internal_audio_loopback_u32_to_dec	(	uint32_t	value,
		uint8_t *	buf )

static

Convert a 32-bit unsigned integer into an ASCII decimal string.

Builds digits least-significant first in a bounded local array, then reverses them into the caller's output buffer without heap use.

Parameters

[in]	value	Integer value to convert.
[out]	buf	Caller buffer, must hold at least 11 bytes.

Returns: Number of bytes written into buf (does not include a NUL).

Return values

1	One byte was written for the value zero.
2..10	The number of decimal digits written for a nonzero value.

Precondition: buf is non-NULL and has room for 11 bytes.; The caller does not require a terminating NUL byte.

Postcondition: Buffer holds the decimal representation, MSD first.; Bytes beyond the returned length are left unchanged.

Note: The 11-byte capacity precondition leaves room for all uint32_t values even though this helper writes at most ten digits.

Since: 0.1.0

< '0'.

< Radix.

< 2^32 - 1 has at most 10 digits.

Definition at line 229 of file main.c.

References RA8_INTERNAL.

Referenced by internal_audio_loopback_print_count().

◆ main()

void main ( void )

Application entry.

The application entry point Reset_Handler hands control to.

Brings up CGC + BSP audio then plays blocks.

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 playback loop forever.; On any HAL init failure the function halts in WFI.

Since: 0.1.0

Definition at line 298 of file main.c.

Variable Documentation

◆ s_audio_loopback_msg_prefix

const uint8_t s_audio_loopback_msg_prefix[] = "audio: "

static

Diagnostic banner emitted every k_audio_loopback_print_period blocks.

Definition at line 80 of file main.c.

Referenced by internal_audio_loopback_print_count().

◆ s_audio_loopback_msg_suffix

const uint8_t s_audio_loopback_msg_suffix[] = " blocks played\r\n"

static

Definition at line 81 of file main.c.

Referenced by internal_audio_loopback_print_count().

◆ s_audio_loopback_silence

const int16_t s_audio_loopback_silence[k_audio_loopback_block_samples] = {}

static

Static stereo silence buffer fed to the CODEC each iteration.

Zero-amplitude PCM keeps the SSIE0 FIFO primed without driving audible output. Replace with a sine LUT (or a pull from an iso-OUT USB endpoint) to produce a tone.

Definition at line 91 of file main.c.

Referenced by main().

Enumerations

Functions

Variables

Detailed Description

Enumeration Type Documentation

◆ audio_loopback_block_t

◆ audio_loopback_chan_t

◆ audio_loopback_config_t

Function Documentation

◆ internal_audio_loopback_init_clocks_and_led()

◆ internal_audio_loopback_init_codec()

◆ internal_audio_loopback_init_console()

◆ internal_audio_loopback_panic_halt()

◆ internal_audio_loopback_print_count()

◆ internal_audio_loopback_u32_to_dec()

◆ main()

Variable Documentation

◆ s_audio_loopback_msg_prefix

◆ s_audio_loopback_msg_suffix

◆ s_audio_loopback_silence