Native USB CDC ACM class layer implementation. More...

#include "ra8_usb_cdc.h"
#include <stdint.h>
#include "ra8_attributes.h"
#include "ra8_check.h"
#include "ra8_err.h"
#include "ra8_log.h"
#include "ra8_usb.h"
#include "ra8_usb_cdc_internal.h"

Include dependency graph for ra8_usb_cdc.c:

Data Structures
struct	ra8_usb_cdc_state_t
	Singleton shadow state for the CDC function. More...

Enumerations
enum	ra8_usb_cdc_setup_field_t : uint8_t { k_ra8_cdc_bm_class_recip_iface = 0x21U , k_ra8_cdc_bm_class_recip_in = 0xA1U , k_ra8_cdc_default_data_bits = 8U , k_ra8_cdc_default_stop_bits = 0U , k_ra8_cdc_default_parity_none = 0U , k_ra8_cdc_line_coding_len = 7U }
	Constants used to decode CDC class-specific SETUPs. More...
enum	ra8_usb_cdc_data_stage_t : uint16_t { k_ra8_cdc_data_stage_polls = 1000U }
	Bound on the polled control-OUT data-stage drain. More...
enum	ra8_usb_cdc_default_baud_t : uint32_t { k_ra8_cdc_default_baud = 9600U }
	9600 baud assembled from the two low bytes above. More...
enum	ra8_usb_cdc_byte_shift_t : uint8_t { k_ra8_cdc_shift_byte0 = 0U , k_ra8_cdc_shift_byte1 = 8U , k_ra8_cdc_shift_byte2 = 16U , k_ra8_cdc_shift_byte3 = 24U }
	Per-byte left-shift constants for the little-endian baud accumulator in internal_apply_line_coding. More...
enum	ra8_usb_cdc_byte_idx_t : uint8_t { k_ra8_cdc_idx_baud_b0 = 0U , k_ra8_cdc_idx_baud_b1 = 1U , k_ra8_cdc_idx_baud_b2 = 2U , k_ra8_cdc_idx_baud_b3 = 3U , k_ra8_cdc_idx_char_format = 4U , k_ra8_cdc_idx_parity_type = 5U , k_ra8_cdc_idx_data_bits = 6U }
	Indices into the 7-byte SET_LINE_CODING payload. More...

Functions
static void	internal_default_coding (ra8_usb_cdc_line_coding_t *coding)
	Internal helper.
static ra8_err_t	internal_configure_pipes (ra8_usb_speed_t speed)
	Configure the three CDC pipes (bulk IN / OUT, intr IN).
static void	internal_apply_line_coding (const uint8_t *data, uint16_t len)
	Apply a host SET_LINE_CODING payload to the cached CDC line coding.
void	ra8_usb_cdc_test_apply_line_coding (const uint8_t *data, uint16_t len)
	Drive the private SET_LINE_CODING decoder from host tests.
ra8_err_t	ra8_usb_cdc_init (ra8_usb_speed_t speed)
	Bring up the CDC ACM function on a chosen USB controller.
ra8_err_t	ra8_usb_cdc_deinit (void)
	Tear down the CDC function and release the underlying controller.
ra8_err_t	ra8_usb_cdc_attach (bool attached)
	Raise / drop the D+ pull-up to advertise the CDC function.
ra8_err_t	ra8_usb_cdc_send (const uint8_t *data, uint16_t len)
	Send a chunk of bytes IN (device -> host).
ra8_err_t	ra8_usb_cdc_recv (uint8_t out_buf, uint16_t inout_len)
	Drain a chunk of bytes OUT (host -> device).
static ra8_err_t	internal_pull_data_stage (uint8_t buf, uint16_t cap, uint16_t out_len)
	Pull the SET_LINE_CODING data stage off EP0 (DCP) once it lands.
static ra8_err_t	internal_dispatch_class_setup (const ra8_usb_setup_t *setup)
	Decode a CDC class-specific SETUP packet body.
ra8_err_t	ra8_usb_cdc_handle_setup (const ra8_usb_setup_t *setup)
	Process a class-specific SETUP packet.
ra8_err_t	ra8_usb_cdc_get_line_coding (ra8_usb_cdc_line_coding_t *out)
	Get the most recently negotiated line coding.
ra8_err_t	ra8_usb_cdc_get_line_state (bool out_dtr, bool out_rts)
	Get the most recently received DTR / RTS bits.

Variables
static const char *	s_tag = "USBCDC"
static ra8_usb_cdc_state_t	s_state = {}

Detailed Description

Native USB CDC ACM class layer implementation.

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

Glues the device-mode ra8_usb driver to a CDC ACM endpoint set so the host enumerates the board as /dev/ttyACM* (Linux / macOS) or COMn (Windows). Class-specific SETUP requests (SET_LINE_CODING / GET_LINE_CODING / SET_CONTROL_LINE_STATE) are answered locally; the CDC standard descriptors live in the caller's stack so this file does not own VID / PID.

The implementation is from-scratch – there is no FSP r_usb_pcdc source pulled in. Behaviourally it tracks the small subset that the CDC PSTN spec rev 1.20 makes mandatory for an ACM device:

Persistent line-coding shadow (default 9600/8/N/1).
DTR / RTS shadow.
Bulk byte pipe via ra8_usb_queue_in / ra8_usb_queue_out.

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

Definition in file ra8_usb_cdc.c.

Enumeration Type Documentation

◆ ra8_usb_cdc_byte_idx_t

enum ra8_usb_cdc_byte_idx_t : uint8_t

Indices into the 7-byte SET_LINE_CODING payload.

Enumerator
k_ra8_cdc_idx_baud_b0	RA8 cdc index baud b0.
k_ra8_cdc_idx_baud_b1	RA8 cdc index baud b1.
k_ra8_cdc_idx_baud_b2	RA8 cdc index baud b2.
k_ra8_cdc_idx_baud_b3	RA8 cdc index baud b3.
k_ra8_cdc_idx_char_format	RA8 cdc index char format.
k_ra8_cdc_idx_parity_type	RA8 cdc index parity type.
k_ra8_cdc_idx_data_bits	RA8 cdc index data bits.

Definition at line 99 of file ra8_usb_cdc.c.

◆ ra8_usb_cdc_byte_shift_t

enum ra8_usb_cdc_byte_shift_t : uint8_t

Per-byte left-shift constants for the little-endian baud accumulator in internal_apply_line_coding.

Enumerator
k_ra8_cdc_shift_byte0	RA8 cdc shift byte0.
k_ra8_cdc_shift_byte1	RA8 cdc shift byte1.
k_ra8_cdc_shift_byte2	RA8 cdc shift byte2.
k_ra8_cdc_shift_byte3	RA8 cdc shift byte3.

Definition at line 88 of file ra8_usb_cdc.c.

◆ ra8_usb_cdc_data_stage_t

enum ra8_usb_cdc_data_stage_t : uint16_t

Bound on the polled control-OUT data-stage drain.

This layer is polled throughout (ra8_usb_cdc_recv drives the bulk pipe the same way), so the SET_LINE_CODING data stage is drained by a bounded poll rather than an ISR callback. The bound exists so the SETUP path can never spin: the RA8 SIE ACKs the host's OUT packet into the DCP bank as soon as ra8_usb_dcp_out_arm sets PID = BUF, so the packet lands within a few bus microframes or the host has abandoned the transfer. Exhausting the bound is not an error path for the caller – the request is still ACKed, exactly as it was before the data stage was captured at all.

Invariant: The loop in internal_pull_data_stage runs at most k_ra8_cdc_data_stage_polls times (NASA P10 Rule 2).

See also: internal_pull_data_stage()

Since: 0.1.0

Enumerator
k_ra8_cdc_data_stage_polls	Max ra8_usb_dcp_out_read attempts.

Definition at line 71 of file ra8_usb_cdc.c.

◆ ra8_usb_cdc_default_baud_t

enum ra8_usb_cdc_default_baud_t : uint32_t

9600 baud assembled from the two low bytes above.

Enumerator
k_ra8_cdc_default_baud	RA8 cdc default baud.

Definition at line 79 of file ra8_usb_cdc.c.

◆ ra8_usb_cdc_setup_field_t

enum ra8_usb_cdc_setup_field_t : uint8_t

Constants used to decode CDC class-specific SETUPs.

Enumerator
k_ra8_cdc_bm_class_recip_iface	Class \| Interface \| Out.
k_ra8_cdc_bm_class_recip_in	Class \| Interface \| In.
k_ra8_cdc_default_data_bits	8 data bits.
k_ra8_cdc_default_stop_bits	1 stop bit.
k_ra8_cdc_default_parity_none	No parity.
k_ra8_cdc_line_coding_len	7-byte payload length.

Definition at line 45 of file ra8_usb_cdc.c.

Function Documentation

◆ internal_apply_line_coding()

void internal_apply_line_coding	(	const uint8_t *	data,
		uint16_t	len )

static

Apply a host SET_LINE_CODING payload to the cached CDC line coding.

Decodes the little-endian seven-byte USB CDC PSTN line-coding structure. The 32-bit DTE baud rate is assembled from bytes zero through three, followed by the character-format, parity-type, and data-bit fields. A null pointer or a short payload leaves the cached coding untouched.

Parameters

[in]	data	Pointer to the line-coding payload in host byte order; may be null to exercise the reject path.
[in]	len	Length of `data` in bytes.

Precondition: The CDC state has been initialized by ra8_usb_cdc_init().; When data is non-null, it references at least len readable bytes.

Postcondition: A valid seven-byte payload replaces every cached line-coding field.; A null or short payload leaves the cached line coding unchanged.

Note: Not thread-safe; production calls originate in the USB control path.

MC/DC:

Decision (data == nullptr) || (len < 7) uses N+1 = 3 vectors:

non-null data, length 7: false control vector
null data, length 7: first condition independently makes the result true
non-null data, length 6: second condition independently makes it true

Since: 0.1.0

Definition at line 225 of file ra8_usb_cdc.c.

References k_ra8_cdc_idx_baud_b0, k_ra8_cdc_idx_baud_b1, k_ra8_cdc_idx_baud_b2, k_ra8_cdc_idx_baud_b3, k_ra8_cdc_idx_char_format, k_ra8_cdc_idx_data_bits, k_ra8_cdc_idx_parity_type, k_ra8_cdc_line_coding_len, k_ra8_cdc_shift_byte1, k_ra8_cdc_shift_byte2, k_ra8_cdc_shift_byte3, and s_state.

Referenced by internal_dispatch_class_setup(), and ra8_usb_cdc_test_apply_line_coding().

◆ internal_configure_pipes()

ra8_err_t internal_configure_pipes ( ra8_usb_speed_t speed )

static

Configure the three CDC pipes (bulk IN / OUT, intr IN).

See implementation.

Parameters

[in] speed See implementation.

Returns: Result code.

Return values

k_ra8_ok Operation succeeded.

Precondition: Module state is consistent.; Module state is consistent.

Postcondition: Caller-visible state matches the documented contract.; Caller-visible state matches the documented contract.

Note: Not thread-safe unless documented otherwise.

Since: 0.1.0

Definition at line 163 of file ra8_usb_cdc.c.

References k_ra8_cdc_bulk_max_packet_fs, k_ra8_cdc_bulk_max_packet_hs, k_ra8_cdc_ep_bulk_in_addr, k_ra8_cdc_ep_bulk_out_addr, k_ra8_cdc_ep_intr_in_addr, k_ra8_cdc_intr_max_packet, k_ra8_cdc_pipe_bulk_in, k_ra8_cdc_pipe_bulk_out, k_ra8_cdc_pipe_intr_in, k_ra8_usb_ep_dir_in, k_ra8_usb_ep_dir_out, k_ra8_usb_ep_type_bulk, k_ra8_usb_ep_type_intr, k_ra8_usb_speed_hs, RA8_RETURN_ON_ERROR, ra8_usb_configure_endpoint(), and s_tag.

◆ internal_default_coding()

void internal_default_coding ( ra8_usb_cdc_line_coding_t * coding )

static

Internal helper.

See implementation.

Parameters

[in] coding See implementation.

Precondition: Module state is consistent.; Module state is consistent.

Postcondition: Caller-visible state matches the documented contract.; Caller-visible state matches the documented contract.

Note: Not thread-safe unless documented otherwise.

Since: 0.1.0

Definition at line 140 of file ra8_usb_cdc.c.

References ra8_usb_cdc_line_coding_t::char_format, ra8_usb_cdc_line_coding_t::data_bits, ra8_usb_cdc_line_coding_t::dte_rate, k_ra8_cdc_default_baud, k_ra8_cdc_default_data_bits, k_ra8_cdc_default_parity_none, k_ra8_cdc_default_stop_bits, and ra8_usb_cdc_line_coding_t::parity_type.

Referenced by ra8_usb_cdc_init().

◆ internal_dispatch_class_setup()

ra8_err_t internal_dispatch_class_setup ( const ra8_usb_setup_t * setup )

static

Decode a CDC class-specific SETUP packet body.

Returns: ra8_ok on success, or an error code that the public ra8_usb_cdc_handle_setup propagates verbatim.

See implementation.

Parameters

[in] setup See implementation.

Return values

k_ra8_ok Operation succeeded.

Precondition: Module state is consistent.; Module state is consistent.

Postcondition: Caller-visible state matches the documented contract.; Caller-visible state matches the documented contract.

Note: Not thread-safe unless documented otherwise.

Since: 0.1.0

Definition at line 414 of file ra8_usb_cdc.c.

References ra8_usb_setup_t::b_request, internal_apply_line_coding(), internal_pull_data_stage(), k_ra8_cdc_line_coding_len, k_ra8_cdc_line_state_dtr, k_ra8_cdc_line_state_rts, k_ra8_cdc_req_get_line_coding, k_ra8_cdc_req_set_control_line_state, k_ra8_cdc_req_set_line_coding, k_ra8_err_not_supported, k_ra8_ok, ra8_usb_control_response(), s_state, and ra8_usb_setup_t::w_value.

Referenced by ra8_usb_cdc_handle_setup().

◆ internal_pull_data_stage()

ra8_err_t internal_pull_data_stage	(	uint8_t *	buf,
		uint16_t	cap,
		uint16_t *	out_len )

static

Pull the SET_LINE_CODING data stage off EP0 (DCP) once it lands.

Drives the two-step control-OUT receive the device driver exposes: ra8_usb_dcp_out_arm sets DCPCTR.PID = BUF so the SIE ACKs the host's OUT token into the DCP bank, then ra8_usb_dcp_out_read drains that bank. The read reports k_ra8_err_no_data until the packet actually lands, so this polls it up to k_ra8_cdc_data_stage_polls times – matching the polled style of the rest of this layer (ra8_usb_cdc_recv drives the bulk-OUT pipe the same way) rather than requiring the caller to own a BRDY interrupt.

The bound is fail-soft by design: if the payload never arrives, the caller simply leaves the cached line coding untouched and still ACKs the status stage, which is exactly what the layer did before the data stage was captured. A host that does complete the transfer now has its baud rate, framing and parity recorded and visible through ra8_usb_cdc_get_line_coding.

Parameters

[out]	buf	Destination for the payload; must hold `cap` bytes.
[in]	cap	Capacity of `buf` in bytes.
[out]	out_len	Receives the host's payload length in bytes.

Returns: Result code.

Return values

k_ra8_ok	A packet was drained; *out_len is its length.
k_ra8_err_null_ptr	`buf` or `out_len` is NULL.
k_ra8_err_invalid_arg	`cap` is zero.
k_ra8_err_no_data	The payload did not land within the poll bound.
other	Propagated from the arm / read pair.

Precondition: A control-OUT SETUP with wLength > 0 was just decoded.; s_state.speed names the controller that saw the SETUP.

Postcondition: On k_ra8_ok *out_len bytes of payload are resident in buf.; On any error the cached line coding is left untouched.

Note: Not thread-safe; bounded, so it cannot spin.

See also: ra8_usb_dcp_out_arm(); ra8_usb_dcp_out_read()

Since: 0.1.0

Definition at line 375 of file ra8_usb_cdc.c.

References internal_pull_data_stage(), k_ra8_cdc_data_stage_polls, k_ra8_err_invalid_arg, k_ra8_err_no_data, k_ra8_ok, RA8_CHECK_NULL_PTR, ra8_usb_dcp_out_arm(), ra8_usb_dcp_out_read(), s_state, and s_tag.

Referenced by internal_dispatch_class_setup(), and internal_pull_data_stage().

◆ ra8_usb_cdc_attach()

ra8_err_t ra8_usb_cdc_attach ( bool attached )

nodiscard

Raise / drop the D+ pull-up to advertise the CDC function.

Parameters

[in] attached true to attach, false to detach.

Returns: ra8_err_t error code.

Return values

k_ra8_ok	State updated.
k_ra8_err_invalid_state	CDC not initialized.

Precondition: ra8_usb_cdc_init succeeded.

Postcondition: On success, the controller's SYSCFG.DPRPU matches attached.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 290 of file ra8_usb_cdc.c.

References k_ra8_err_invalid_state, ra8_usb_device_attach(), and s_state.

◆ ra8_usb_cdc_deinit()

ra8_err_t ra8_usb_cdc_deinit ( void )

nodiscard

Tear down the CDC function and release the underlying controller.

Returns: ra8_err_t error code.

Return values

k_ra8_ok	Released.
k_ra8_err_invalid_state	CDC was never initialized.

Precondition: Single-threaded shutdown context.

Postcondition: Subsequent CDC API calls return k_ra8_err_invalid_state.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 277 of file ra8_usb_cdc.c.

References k_ra8_err_invalid_state, ra8_usb_device_attach(), ra8_usb_device_deinit(), and s_state.

◆ ra8_usb_cdc_get_line_coding()

ra8_err_t ra8_usb_cdc_get_line_coding ( ra8_usb_cdc_line_coding_t * out )

nodiscard

Get the most recently negotiated line coding.

Parameters

[out] out Receives the 7-byte coding payload.

Returns: ra8_err_t error code.

Return values

k_ra8_ok	Copied.
k_ra8_err_invalid_arg	out was NULL.
k_ra8_err_invalid_state	CDC not initialized.

Precondition: out non-NULL.

Postcondition: No internal state mutated.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 457 of file ra8_usb_cdc.c.

References k_ra8_err_invalid_state, k_ra8_ok, RA8_CHECK_NULL_PTR, s_state, and s_tag.

◆ ra8_usb_cdc_get_line_state()

ra8_err_t ra8_usb_cdc_get_line_state	(	bool *	out_dtr,
		bool *	out_rts )

nodiscard

Get the most recently received DTR / RTS bits.

Parameters

[out]	out_dtr	true if DTR asserted.
[out]	out_rts	true if RTS asserted.

Returns: ra8_err_t error code.

Return values

k_ra8_ok	State copied.
k_ra8_err_invalid_arg	out_dtr / out_rts were NULL.
k_ra8_err_invalid_state	CDC not initialized.

Precondition: Output pointers non-NULL.

Postcondition: No internal state mutated.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 467 of file ra8_usb_cdc.c.

References k_ra8_err_invalid_state, k_ra8_ok, RA8_CHECK_NULL_PTR, s_state, and s_tag.

◆ ra8_usb_cdc_handle_setup()

ra8_err_t ra8_usb_cdc_handle_setup ( const ra8_usb_setup_t * setup )

nodiscard

Process a class-specific SETUP packet.

Switches on b_request and either updates the stored line coding, returns the line coding payload, or stores the DTR / RTS bits. Standard (non-class) SETUPs are rejected with k_ra8_err_not_supported so the caller can fall back to its own standard-request handler.

Parameters

[in] setup The SETUP packet returned by ra8_usb_read_setup_if_valid.

Returns: ra8_err_t error code.

Return values

k_ra8_ok	SETUP handled (status stage queued internally).
k_ra8_err_invalid_state	CDC not initialized.
k_ra8_err_invalid_arg	setup was NULL.
k_ra8_err_not_supported	bRequest is not a CDC ACM request this layer cares about.

Precondition: ra8_usb_cdc_init succeeded.

Postcondition: Stored line coding / line state updated.

Note: Call from the CTRT ISR path of ra8_usb.

Since: 0.1.0

Definition at line 444 of file ra8_usb_cdc.c.

References ra8_usb_setup_t::bm_request_type, internal_dispatch_class_setup(), k_ra8_cdc_bm_class_recip_iface, k_ra8_cdc_bm_class_recip_in, k_ra8_err_invalid_state, k_ra8_err_not_supported, RA8_CHECK_NULL_PTR, s_state, and s_tag.

◆ ra8_usb_cdc_init()

ra8_err_t ra8_usb_cdc_init ( ra8_usb_speed_t speed )

nodiscard

Bring up the CDC ACM function on a chosen USB controller.

Initialises the underlying ra8_usb driver for speed, configures PIPE1 (bulk IN), PIPE2 (bulk OUT), PIPE6 (interrupt IN), seeds a default 9600/8/N/1 line coding, and stores DTR/RTS = 0. The D+ pull-up stays down – the caller raises it via ra8_usb_cdc_attach once it is ready to enumerate.

Parameters

[in] speed Which USB controller (FS or HS).

Returns: ra8_err_t error code.

Return values

k_ra8_ok	CDC function ready.
k_ra8_err_invalid_arg	speed out of range.
k_ra8_err_hw_init_failed	Underlying ra8_usb_device_init failed.

Precondition: Single-threaded init context.

Postcondition: ra8_usb_cdc_get_line_coding returns 9600/8/N/1.; Bulk + interrupt pipes are configured but not attached.

Note: Not thread-safe.

See also: ra8_usb_cdc_attach

Since: 0.1.0

Definition at line 251 of file ra8_usb_cdc.c.

References internal_configure_pipes(), internal_default_coding(), k_ra8_err_hw_init_failed, k_ra8_err_invalid_arg, k_ra8_ok, k_ra8_usb_speed_fs, k_ra8_usb_speed_hs, ra8_log_error_val, ra8_log_info, ra8_usb_device_deinit(), ra8_usb_device_init(), s_state, and s_tag.

◆ ra8_usb_cdc_recv()

ra8_err_t ra8_usb_cdc_recv	(	uint8_t *	out_buf,
		uint16_t *	inout_len )

nodiscard

Drain a chunk of bytes OUT (host -> device).

Parameters

[out]	out_buf	Destination buffer.
[in,out]	inout_len	On entry: capacity. On exit: bytes received.

Returns: ra8_err_t error code.

Return values

k_ra8_ok	Bytes received.
k_ra8_err_no_data	Pipe was empty.
k_ra8_err_invalid_state	CDC not initialized.
k_ra8_err_invalid_arg	Bad pointers / capacity.

Precondition: out_buf, inout_len non-NULL, *inout_len > 0.

Postcondition: On success *inout_len reflects the actual byte count.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 314 of file ra8_usb_cdc.c.

References k_ra8_cdc_pipe_bulk_out, k_ra8_err_invalid_arg, k_ra8_err_invalid_state, RA8_CHECK_NULL_PTR, ra8_usb_queue_out(), s_state, and s_tag.

◆ ra8_usb_cdc_send()

ra8_err_t ra8_usb_cdc_send	(	const uint8_t *	data,
		uint16_t	len )

nodiscard

Send a chunk of bytes IN (device -> host).

Parameters

[in]	data	Buffer to send.
[in]	len	Byte count, 0..bulk_max_packet of the speed.

Returns: ra8_err_t error code.

Return values

k_ra8_ok	Transfer queued.
k_ra8_err_invalid_state	CDC not initialized.
k_ra8_err_invalid_arg	Bad data / len.

Precondition: ra8_usb_cdc_init succeeded.

Postcondition: Bytes are visible on the host's TTY after the next IN token.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 303 of file ra8_usb_cdc.c.

References k_ra8_cdc_pipe_bulk_in, k_ra8_err_invalid_arg, k_ra8_err_invalid_state, ra8_usb_queue_in(), and s_state.

◆ ra8_usb_cdc_test_apply_line_coding()

void ra8_usb_cdc_test_apply_line_coding	(	const uint8_t *	data,
		uint16_t	len )

Drive the private SET_LINE_CODING decoder from host tests.

Forwards the caller-owned payload to the same private decoder used by the CDC SETUP handler. This is a test-access seam only; production code continues to call the private helper directly.

Parameters

[in]	data	Pointer to the line-coding payload in host byte order; may be null to exercise the reject path.
[in]	len	Length of `data` in bytes.

Precondition: The CDC state has been initialized by ra8_usb_cdc_init().; When data is non-null, it references at least len readable bytes.

Postcondition: A valid seven-byte payload replaces every cached line-coding field.; A null or short payload leaves the cached line coding unchanged.

Note: Not thread-safe; production calls originate in the USB control path.

MC/DC:

Decision (data == nullptr) || (len < 7) uses N+1 = 3 vectors:

non-null data, length 7: false control vector
null data, length 7: first condition independently makes the result true
non-null data, length 6: second condition independently makes it true

Since: 0.1.0

Definition at line 241 of file ra8_usb_cdc.c.

References internal_apply_line_coding().

Variable Documentation

◆ s_state

ra8_usb_cdc_state_t s_state = {}

static

Definition at line 121 of file ra8_usb_cdc.c.

◆ s_tag

const char* s_tag = "USBCDC"

static

Definition at line 39 of file ra8_usb_cdc.c.

Data Structures

Enumerations

Functions

Variables

Detailed Description

Enumeration Type Documentation

◆ ra8_usb_cdc_byte_idx_t

◆ ra8_usb_cdc_byte_shift_t

◆ ra8_usb_cdc_data_stage_t

◆ ra8_usb_cdc_default_baud_t

◆ ra8_usb_cdc_setup_field_t

Function Documentation

◆ internal_apply_line_coding()

◆ internal_configure_pipes()

◆ internal_default_coding()

◆ internal_dispatch_class_setup()

◆ internal_pull_data_stage()

◆ ra8_usb_cdc_attach()

◆ ra8_usb_cdc_deinit()

◆ ra8_usb_cdc_get_line_coding()

◆ ra8_usb_cdc_get_line_state()

◆ ra8_usb_cdc_handle_setup()

◆ ra8_usb_cdc_init()

◆ ra8_usb_cdc_recv()

◆ ra8_usb_cdc_send()

◆ ra8_usb_cdc_test_apply_line_coding()

Variable Documentation

◆ s_state

◆ s_tag