ra8_sci_lin.h File Reference

LIN (Local Interconnect Network) commander + responder driver on SCI_B. More...

#include <stdint.h>
#include "ra8_err.h"
#include "ra8_sci.h"

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Data Structures
struct	ra8_sci_lin_cfg_t
	Configuration descriptor for ra8_sci_lin_init. More...

Enumerations
enum	ra8_sci_lin_limits_t : uint8_t { k_ra8_sci_lin_id_max = 0x3FU }
	Public range limits for the LIN frame identifier. More...
enum	ra8_sci_lin_timer_clk_t : uint8_t {   k_ra8_sci_lin_clk_div4 = 1U ,   k_ra8_sci_lin_clk_div16 = 2U ,   k_ra8_sci_lin_clk_div64 = 3U }
	Break-field timer clock divider (maps to SCI_B XCR0.TCSS[1:0]). More...
enum	ra8_sci_lin_role_t : uint8_t {   k_ra8_sci_lin_role_commander = 0U ,   k_ra8_sci_lin_role_responder = 1U }
	Selects whether the channel drives (commander) or detects (responder) the LIN frame header. More...
enum	ra8_sci_lin_checksum_mode_t : uint8_t {   k_ra8_sci_lin_checksum_classic = 0U ,   k_ra8_sci_lin_checksum_enhanced = 1U }
	Selector for the classic vs. More...

Functions
ra8_err_t	ra8_sci_lin_init (uint8_t channel, const ra8_sci_lin_cfg_t *cfg)
	Configure an SCI_B channel for a LIN role (commander or responder).
ra8_err_t	ra8_sci_lin_send_break (uint8_t channel)
	Emit a LIN break field on the channel's TXD line.
ra8_err_t	ra8_sci_lin_send_header (uint8_t channel, uint8_t id)
	Transmit a full LIN header: break + SYNC (0x55) + PID.
ra8_err_t	ra8_sci_lin_break_detected (uint8_t channel, bool *out_detected)
	Report whether the responder's break-field detector has fired.
ra8_err_t	ra8_sci_lin_wait_break (uint8_t channel)
	Block until the responder detects a break field (XSR0.BFDF set).
ra8_err_t	ra8_sci_lin_clear_status (uint8_t channel)
	Clear the Simple-LIN status latches (XSR0) via XFCLR.
ra8_err_t	ra8_sci_lin_send_response (uint8_t channel, ra8_sci_lin_checksum_mode_t mode, uint8_t pid, const uint8_t *data, uint8_t len)
	Publish a LIN response: data bytes followed by the checksum.
ra8_err_t	ra8_sci_lin_read_response (uint8_t channel, uint8_t *out_data, uint8_t len, uint8_t *out_checksum)
	Read a LIN response: len data bytes plus one checksum byte.
ra8_err_t	ra8_sci_lin_check_header (uint8_t sync, uint8_t pid, uint8_t *out_id, bool *out_valid)
	Validate a received LIN header: SYNC byte + protected identifier.
ra8_err_t	ra8_sci_lin_check_response (ra8_sci_lin_checksum_mode_t mode, uint8_t pid, const uint8_t *data, uint8_t len, uint8_t received, bool *out_valid)
	Verify a received LIN response checksum against the data field.
uint8_t	ra8_sci_lin_pid (uint8_t id)
	Compute the LIN protected identifier (PID) from a frame id.
ra8_err_t	ra8_sci_lin_checksum (ra8_sci_lin_checksum_mode_t mode, uint8_t pid, const uint8_t *data, uint8_t len, uint8_t *out_checksum)
	Compute a classic or enhanced LIN checksum over a data field.

Detailed Description

LIN (Local Interconnect Network) commander + responder driver on SCI_B.

Tag

[Ring 3 / HAL] {World: NS}

LIN is a single-wire, single-commander serial protocol layered on top of a standard UART. The commander node drives every frame header; it emits a BREAK field (at least 13 dominant bit-times), a SYNC byte (0x55), and a protected identifier (PID = a 6-bit frame id plus two parity bits). The header is then followed by a response phase – data bytes and a checksum – published by whichever node the frame id assigns as the transmitter (commander or responder).

This driver implements both LIN roles on the SCI_B Simple-LIN sub-mode:

• Commander (k_ra8_sci_lin_role_commander): hardware GENERATES the break field via the break-field timer (XCR0.TCSS clock, XCR0.BFE, XCR2.BFLW length, XCR1.TCST trigger); SYNC and PID are clocked out as ordinary UART frames.
• Responder (k_ra8_sci_lin_role_responder): hardware DETECTS the break field via Start-Frame detection (XCR1.SDST) and reports it through XSR0.BFDF; the sync field is measured by the bit-rate measurement counter (XCR1.BMEN -> XSR1.TCNT).

Inclusive-terminology note

The LIN specification's commander node is the bus controller and its subordinate nodes are termed "responders" here. The legacy LIN node words are avoided in favour of Commander / Responder, per the project terminology standard.

This driver targets the SCI_B Simple-LIN sub-mode (HUM Ch 38.11 "Simple LIN Mode", p 2338; register-level break generation via XCR0/XCR1/XCR2 and detection via XSR0/XSR1/XFCLR). It builds on the async-UART bring-up in ra8_sci.h: ra8_sci_lin_init configures the baud / framing through the base UART path and then switches CCR3.MOD to Simple LIN and programs the role-specific break-field timer / detector.

This header includes ra8_sci.h one-directionally for the base configuration type (ra8_sci_cfg_t). ra8_sci.h does NOT include this header back; consumers that need the LIN API include ra8_sci_lin.h directly.

API surface

Lifecycle:

• ra8_sci_lin_init – configure SCI_B for a LIN role

Commander frame generation:

• ra8_sci_lin_send_break – emit the break field
• ra8_sci_lin_send_header – break + SYNC (0x55) + PID

Responder frame detection:

• ra8_sci_lin_break_detected– poll XSR0.BFDF once (non-blocking)
• ra8_sci_lin_wait_break – block until a break field is detected
• ra8_sci_lin_clear_status – clear the XSR0 LIN latches via XFCLR
• ra8_sci_lin_check_header – pure: validate a received SYNC + PID

Response (data) phase, either role:

• ra8_sci_lin_send_response – publish data bytes + checksum
• ra8_sci_lin_read_response – subscribe: read data bytes + checksum
• ra8_sci_lin_check_response– pure: verify a received response checksum

Pure helpers:

• ra8_sci_lin_pid – pure: 6-bit id -> protected identifier
• ra8_sci_lin_checksum – pure: classic / enhanced LIN checksum

Copyright

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

Definition in file ra8_sci_lin.h.

Enumeration Type Documentation

ra8_sci_lin_checksum_mode_t

enum ra8_sci_lin_checksum_mode_t : uint8_t

Selector for the classic vs.

enhanced LIN checksum.

Classic (LIN 1.x) sums only the data bytes; enhanced (LIN 2.x) folds the protected identifier into the sum as well. Both then take the inverted modulo-255 sum.

Enumerator
k_ra8_sci_lin_checksum_classic	LIN 1.x: sum of data bytes only.
k_ra8_sci_lin_checksum_enhanced	LIN 2.x: sum of PID + data bytes.

Definition at line 144 of file ra8_sci_lin.h.

ra8_sci_lin_limits_t

enum ra8_sci_lin_limits_t : uint8_t

Public range limits for the LIN frame identifier.

The LIN protected identifier carries a 6-bit frame id, so the largest legal value passed to ra8_sci_lin_send_header is 0x3F (63).

Enumerator
k_ra8_sci_lin_id_max	Highest legal 6-bit LIN frame id.

Definition at line 99 of file ra8_sci_lin.h.

ra8_sci_lin_role_t

enum ra8_sci_lin_role_t : uint8_t

Selects whether the channel drives (commander) or detects (responder) the LIN frame header.

A LIN bus has exactly one commander that generates every frame header (break + sync + PID) and any number of responders that detect it. The two roles program different Simple-LIN control bits at init: the commander arms the break-field output timer (XCR1.TCST is pulsed per frame), while the responder arms Start-Frame detection (XCR1.SDST) plus bit-rate measurement (XCR1.BMEN) so the hardware flags an inbound break in XSR0.BFDF and measures the sync field into XSR1.TCNT.

Enumerator
k_ra8_sci_lin_role_commander	Generate the header (bus controller).
k_ra8_sci_lin_role_responder	Detect the header (subordinate node).

Definition at line 131 of file ra8_sci_lin.h.

ra8_sci_lin_timer_clk_t

enum ra8_sci_lin_timer_clk_t : uint8_t

Break-field timer clock divider (maps to SCI_B XCR0.TCSS[1:0]).

Selects the divider applied to the Simple-LIN module timer clock (TCLK) that times the break field. The enumerator values equal the on-chip XCR0.TCSS encodings (HUM Ch 38.2.14, p 2221), so no translation table is needed.

Enumerator
k_ra8_sci_lin_clk_div4	Break timer clock = TCLK / 4.
k_ra8_sci_lin_clk_div16	Break timer clock = TCLK / 16.
k_ra8_sci_lin_clk_div64	Break timer clock = TCLK / 64.

Definition at line 112 of file ra8_sci_lin.h.

Function Documentation

ra8_sci_lin_break_detected()

ra8_err_t ra8_sci_lin_break_detected ( uint8_t channel, bool * out_detected )

nodiscard

Report whether the responder's break-field detector has fired.

Reads XSR0.BFDF once (non-blocking) and writes its state to *out_detected. On a responder channel the Simple-LIN Start-Frame detector sets BFDF when it sees a dominant span at least as long as the configured break-field length; the flag stays set until cleared through ra8_sci_lin_clear_status. Reads no data and modifies no hardware.

Parameters

[in]	channel	SCI channel number (0..9).
[out]	out_detected	Receives true if XSR0.BFDF is set, else false.

Returns

ra8_err_t error code.

Return values

k_ra8_ok	Flag state written to *out_detected.
k_ra8_err_null_ptr	out_detected is NULL or channel out of range.

Precondition

out_detected is non-NULL.

Channel previously configured as a responder via ra8_sci_lin_init.

Postcondition

*out_detected reflects the current XSR0.BFDF bit.

No hardware register is modified.

Note

Thread safety: not thread-safe.

See also

ra8_sci_lin_wait_break

Since

0.1.0

Definition at line 367 of file ra8_sci_lin.c.

References k_ra8_ok, k_ra8_sci_xsr0_bit_bfdf, RA8_CHECK_NULL_PTR, ra8_sci(), s_tag, and r_sci_regs_t::XSR0.

ra8_sci_lin_check_header()

ra8_err_t ra8_sci_lin_check_header ( uint8_t sync, uint8_t pid, uint8_t * out_id, bool * out_valid )

nodiscard

Validate a received LIN header: SYNC byte + protected identifier.

A responder accepts a header only when BOTH the SYNC field equals 0x55 AND the received PID's parity bits match the parity recomputed from its low 6 bits. This pure predicate performs exactly that compound check, writing the extracted 6-bit frame id to *out_id and the accept decision to *out_valid. Pure: touches no hardware register.

Parameters

[in]	sync	The received SYNC field byte (must be 0x55).
[in]	pid	The received protected-identifier byte.
[out]	out_id	Receives the low 6 bits of pid (the frame id).
[out]	out_valid	Receives true iff SYNC == 0x55 and PID parity is OK.

Returns

ra8_err_t error code.

Return values

k_ra8_ok	Decision written to *out_valid / *out_id.
k_ra8_err_null_ptr	out_id or out_valid is NULL.

Precondition

out_id is non-NULL.

out_valid is non-NULL.

Postcondition

*out_id == pid & 0x3F.

*out_valid is true only for a well-formed SYNC + PID pair.

Note

Thread safety: pure function; safe to call concurrently.

See also

ra8_sci_lin_pid

Since

0.1.0

Definition at line 494 of file ra8_sci_lin.c.

References k_ra8_ok, k_ra8_sci_lin_id_mask, k_ra8_sci_lin_sync_byte, RA8_CHECK_NULL_PTR, ra8_sci_lin_pid(), and s_tag.

ra8_sci_lin_check_response()

ra8_err_t ra8_sci_lin_check_response ( ra8_sci_lin_checksum_mode_t mode, uint8_t pid, const uint8_t * data, uint8_t len, uint8_t received, bool * out_valid )

nodiscard

Verify a received LIN response checksum against the data field.

Recomputes the classic or enhanced checksum over data (and pid for the enhanced mode) with ra8_sci_lin_checksum and compares it to the received checksum byte, writing the match result to *out_valid. Pure: touches no hardware register. Pair with ra8_sci_lin_read_response to validate an inbound response.

Parameters

[in]	mode	Classic (data only) or enhanced (PID + data).
[in]	pid	Protected identifier, folded in for enhanced mode.
[in]	data	Data-field byte buffer; non-NULL when len > 0.
[in]	len	Number of data bytes (0..8).
[in]	received	The checksum byte received on the wire.
[out]	out_valid	Receives true iff the recomputed checksum matches.

Returns

ra8_err_t error code.

Return values

k_ra8_ok	Decision written to *out_valid.
k_ra8_err_null_ptr	out_valid is NULL, or data NULL with len > 0.
k_ra8_err_invalid_arg	mode is not a defined checksum mode.

Precondition

out_valid is non-NULL.

data is non-NULL whenever len > 0.

Postcondition

*out_valid is true only when the checksum recomputes exactly.

No input buffer is modified.

Note

Thread safety: pure function; safe to call concurrently.

See also

ra8_sci_lin_read_response

ra8_sci_lin_checksum

Since

0.1.0

Definition at line 509 of file ra8_sci_lin.c.

References k_ra8_ok, RA8_CHECK_NULL_PTR, RA8_RETURN_ON_ERROR, ra8_sci_lin_checksum(), and s_tag.

ra8_sci_lin_checksum()

ra8_err_t ra8_sci_lin_checksum ( ra8_sci_lin_checksum_mode_t mode, uint8_t pid, const uint8_t * data, uint8_t len, uint8_t * out_checksum )

nodiscard

Compute a classic or enhanced LIN checksum over a data field.

Sums the data bytes (and, for k_ra8_sci_lin_checksum_enhanced, the protected identifier pid) into an accumulator, folds the carry bits back into the low byte to form the modulo-255 sum, and returns the one's complement of that sum. Pure: touches no hardware register.

Parameters

[in]	mode	Classic (data only) or enhanced (PID + data).
[in]	pid	Protected identifier, folded in only when mode == k_ra8_sci_lin_checksum_enhanced.
[in]	data	Data-field byte buffer; may be NULL only when len == 0.
[in]	len	Number of data bytes (0..8 for standard LIN).
[out]	out_checksum	Receives the 8-bit checksum on success.

Returns

ra8_err_t error code.

Return values

k_ra8_ok	Checksum computed.
k_ra8_err_null_ptr	out_checksum is NULL, or data is NULL while len > 0.
k_ra8_err_invalid_arg	mode is not a defined checksum mode.

Precondition

out_checksum is non-NULL.

data is non-NULL whenever len > 0.

Postcondition

On success, *out_checksum holds the inverted modulo-255 sum.

No input buffer is modified.

Note

Thread safety: pure function; safe to call concurrently.

See also

ra8_sci_lin_pid

Since

0.1.0

Definition at line 465 of file ra8_sci_lin.c.

References internal_lin_fold_complement(), k_ra8_err_invalid_arg, k_ra8_err_null_ptr, k_ra8_ok, k_ra8_sci_lin_checksum_enhanced, RA8_CHECK_NULL_PTR, and s_tag.

Referenced by ra8_sci_lin_check_response(), and ra8_sci_lin_send_response().

ra8_sci_lin_clear_status()

ra8_err_t ra8_sci_lin_clear_status ( uint8_t channel )

nodiscard

Clear the Simple-LIN status latches (XSR0) via XFCLR.

Writes the clear-all-LIN mask to XFCLR, which clears every W1C XSR0 latch (BFDF, AEDF, COF, bus-conflict, and the control-field match flags). A responder calls this after consuming one frame's break / sync detection so the detector is armed clean for the next header.

Parameters

[in]

channel

SCI channel number (0..9).

Returns

ra8_err_t error code.

Return values

k_ra8_ok	LIN status latches cleared.
k_ra8_err_null_ptr	channel out of range.

Precondition

Channel previously configured via ra8_sci_lin_init.

IRQs masked or single-threaded context.

Postcondition

XSR0.BFDF and the other LIN latches read back clear.

No data register is touched.

Note

Thread safety: not thread-safe.

See also

ra8_sci_lin_wait_break

Since

0.1.0

Definition at line 391 of file ra8_sci_lin.c.

References k_ra8_ok, k_ra8_sci_xfclr_default, RA8_CHECK_NULL_PTR, ra8_sci(), s_tag, and r_sci_regs_t::XFCLR.

ra8_sci_lin_init()

ra8_err_t ra8_sci_lin_init ( uint8_t channel, const ra8_sci_lin_cfg_t * cfg )

nodiscard

Configure an SCI_B channel for a LIN role (commander or responder).

First brings the channel up as an async UART (ra8_sci_init with cfg->uart: MSTP gate, baud, framing, TE/RE). It then drops CCR0, switches CCR3.MOD to Simple LIN (110b) while preserving the framing bits the base init programmed, programs the break-field timer clock (XCR0.TCSS) and break-field enable (XCR0.BFE), sets the break-field length (XCR2.BFLW), and re-enables CCR0.TE + CCR0.RE. The XCR1 program depends on cfg->role: a commander leaves XCR1 idle (TCST is pulsed per frame by ra8_sci_lin_send_break); a responder sets XCR1.SDST (Start-Frame detection) and XCR1.BMEN (bit-rate measurement) so the hardware flags an inbound break in XSR0.BFDF (HUM Ch 38.11.2 p 2341).

Parameters

[in]	channel	SCI channel number (0..9).
[in]	cfg	Non-NULL LIN configuration descriptor.

Returns

ra8_err_t error code.

Return values

k_ra8_ok	Channel configured for the requested role.
k_ra8_err_null_ptr	cfg was NULL or channel out of range.
k_ra8_err_invalid_arg	role undefined, timer_clk not a defined divider, or break_field_len exceeds 0xFFFE.
k_ra8_err_hw_init_failed	The underlying ra8_sci_init failed.

Precondition

IRQs masked or single-threaded init context.

ra8_mstp_init has been called.

Postcondition

On success, CCR3.MOD == Simple LIN and the break-field timer is programmed from cfg.

On success, CCR0.TE and CCR0.RE are set, and XCR1 reflects the role.

Note

Thread safety: not thread-safe.

See also

ra8_sci_lin_send_header

ra8_sci_lin_wait_break

Since

0.1.0

Definition at line 306 of file ra8_sci_lin.c.

References ra8_sci_lin_cfg_t::break_field_len, internal_lin_program_mode(), k_ra8_err_invalid_arg, k_ra8_ok, k_ra8_sci_lin_clk_div4, k_ra8_sci_lin_clk_div64, k_ra8_sci_lin_role_responder, k_ra8_sci_xcr2_bflw_max, RA8_CHECK_NULL_PTR, ra8_log_info_val, RA8_RETURN_ON_ERROR, ra8_sci(), ra8_sci_init(), ra8_sci_lin_cfg_t::role, s_tag, ra8_sci_lin_cfg_t::timer_clk, and ra8_sci_lin_cfg_t::uart.

Referenced by lin_hil_setup_or_halt().

ra8_sci_lin_pid()

uint8_t ra8_sci_lin_pid ( uint8_t id )

nodiscard

Compute the LIN protected identifier (PID) from a frame id.

The PID packs the 6-bit frame id in bits 0..5 plus two parity bits: P0 = ID0 ^ ID1 ^ ID2 ^ ID4 in bit 6, and P1 = NOT(ID1 ^ ID3 ^ ID4 ^ ID5) in bit 7 (LIN 2.x parity). Any caller bits above bit 5 are masked off before the parity is computed, so the function is total. Pure: touches no hardware register.

Parameters

[in]

id

LIN frame identifier; only the low 6 bits are significant.

Returns

The 8-bit protected identifier.

Precondition

id is a LIN frame identifier (low 6 bits significant).

No hardware preconditions (pure function).

Postcondition

The low 6 bits of the result equal id & 0x3F.

Bits 6 and 7 hold the computed parity bits P0 and P1.

Note

Thread safety: pure function; safe to call concurrently.

See also

ra8_sci_lin_send_header

Since

0.1.0

Definition at line 446 of file ra8_sci_lin.c.

References k_ra8_sci_lin_bit_mask, k_ra8_sci_lin_id_bit0, k_ra8_sci_lin_id_bit1, k_ra8_sci_lin_id_bit2, k_ra8_sci_lin_id_bit3, k_ra8_sci_lin_id_bit4, k_ra8_sci_lin_id_bit5, k_ra8_sci_lin_id_mask, k_ra8_sci_lin_pid_p0_shift, and k_ra8_sci_lin_pid_p1_shift.

Referenced by lin_hil_send_frame(), ra8_sci_lin_check_header(), and ra8_sci_lin_send_header().

ra8_sci_lin_read_response()

ra8_err_t ra8_sci_lin_read_response ( uint8_t channel, uint8_t * out_data, uint8_t len, uint8_t * out_checksum )

nodiscard

Read a LIN response: len data bytes plus one checksum byte.

Drains len data bytes into out_data and the trailing checksum byte into *out_checksum, each via ra8_sci_putc_polling's receive peer ra8_sci_getc_polling. This is a thin I/O primitive: it does NOT validate the checksum – the caller passes out_data / *out_checksum to ra8_sci_lin_check_response to verify. Used by the receiving node of a frame (the subscriber).

Parameters

[in]	channel	SCI channel number (0..9).
[out]	out_data	Buffer receiving len data bytes.
[in]	len	Number of data bytes to read (1..8).
[out]	out_checksum	Receives the trailing checksum byte.

Returns

ra8_err_t error code.

Return values

k_ra8_ok	len data bytes + checksum read.
k_ra8_err_null_ptr	channel out of range, or out_data / out_checksum is NULL.
k_ra8_err_invalid_arg	len is 0 or > 8.
k_ra8_err_hw_timeout	An RDRF poll timed out mid-frame.

Precondition

Channel previously configured via ra8_sci_lin_init.

out_data holds at least len bytes; out_checksum non-NULL.

Postcondition

On success, out_data[0..len-1] and *out_checksum are filled.

No hardware control register is modified.

Note

Thread safety: not thread-safe.

See also

ra8_sci_lin_check_response

Since

0.1.0

Definition at line 428 of file ra8_sci_lin.c.

References internal_lin_rx_buf(), k_ra8_err_invalid_arg, k_ra8_sci_lin_data_max, RA8_CHECK_NULL_PTR, RA8_RETURN_ON_ERROR, ra8_sci(), ra8_sci_getc_polling(), and s_tag.

ra8_sci_lin_send_break()

ra8_err_t ra8_sci_lin_send_break ( uint8_t channel )

nodiscard

Emit a LIN break field on the channel's TXD line.

Writes 1 to XCR1.TCST, which starts the hardware break-field timer; the SCI_B holds TXD dominant for the (BFLW + 1) x timer-clock period set at init and self-clears TCST when the field completes. The call then blocks (bounded spin) until TCST reads back clear. On the host (RA8_OFF_TARGET) the timer drain is not modelled, so the wait returns success immediately.

Parameters

[in]

channel

SCI channel number (0..9).

Returns

ra8_err_t error code.

Return values

k_ra8_ok	Break field emitted (or fake stub).
k_ra8_err_null_ptr	channel out of range.
k_ra8_err_hw_timeout	TCST did not self-clear within the budget.

Precondition

Channel previously configured via ra8_sci_lin_init.

IRQs masked or single-threaded transmit context.

Postcondition

On success, the break-field timer is idle (XCR1.TCST clear).

No data byte has been pushed to TDR by this call.

Note

Thread safety: not thread-safe.

See also

ra8_sci_lin_send_header

Since

0.1.0

Definition at line 332 of file ra8_sci_lin.c.

References internal_lin_wait_break_done(), k_ra8_sci_xcr1_bit_tcst, RA8_CHECK_NULL_PTR, ra8_sci(), s_tag, and r_sci_regs_t::XCR1.

Referenced by ra8_sci_lin_send_header().

ra8_sci_lin_send_header()

ra8_err_t ra8_sci_lin_send_header ( uint8_t channel, uint8_t id )

nodiscard

Transmit a full LIN header: break + SYNC (0x55) + PID.

Emits the break field (ra8_sci_lin_send_break), then sends the SYNC byte 0x55 and the protected identifier as two ordinary UART frames via ra8_sci_putc_polling. The PID is computed from id with ra8_sci_lin_pid (6-bit id plus the two LIN parity bits).

Parameters

[in]	channel	SCI channel number (0..9).
[in]	id	6-bit LIN frame identifier (0..63).

Returns

ra8_err_t error code.

Return values

k_ra8_ok	Header transmitted.
k_ra8_err_null_ptr	channel out of range.
k_ra8_err_invalid_arg	id exceeds 63.
k_ra8_err_hw_timeout	A TDRE poll or the break wait timed out.

Precondition

Channel previously configured via ra8_sci_lin_init.

id <= k_ra8_sci_lin_id_max.

Postcondition

On success, the break field, SYNC, and PID have been clocked out.

TDR holds the protected identifier (the final byte written).

Note

Thread safety: not thread-safe.

See also

ra8_sci_lin_pid

ra8_sci_lin_send_break

Since

0.1.0

Definition at line 344 of file ra8_sci_lin.c.

References k_ra8_err_invalid_arg, k_ra8_ok, k_ra8_sci_lin_id_max, k_ra8_sci_lin_sync_byte, RA8_CHECK_NULL_PTR, RA8_RETURN_ON_ERROR, ra8_sci(), ra8_sci_lin_pid(), ra8_sci_lin_send_break(), ra8_sci_putc_polling(), and s_tag.

Referenced by lin_hil_send_frame().

ra8_sci_lin_send_response()

ra8_err_t ra8_sci_lin_send_response ( uint8_t channel, ra8_sci_lin_checksum_mode_t mode, uint8_t pid, const uint8_t * data, uint8_t len )

nodiscard

Publish a LIN response: data bytes followed by the checksum.

Computes the classic or enhanced checksum over data (folding pid in for the enhanced mode) via ra8_sci_lin_checksum, then clocks the len data bytes and the checksum byte out as ordinary UART frames with ra8_sci_putc_polling. Used by the transmitting node of a frame: the commander for a commander-to-responder frame, or a responder for a responder-to-commander frame. The caller must already have sent (as commander) or detected (as responder) the header.

Parameters

[in]	channel	SCI channel number (0..9).
[in]	mode	Classic (data only) or enhanced (PID + data) checksum.
[in]	pid	Protected identifier, folded into the enhanced sum.
[in]	data	Data-field byte buffer; non-NULL when len > 0.
[in]	len	Number of data bytes (1..8 for standard LIN).

Returns

ra8_err_t error code.

Return values

k_ra8_ok	Data + checksum clocked out.
k_ra8_err_null_ptr	channel out of range, or data NULL with len > 0.
k_ra8_err_invalid_arg	mode undefined or len is 0 or > 8.
k_ra8_err_hw_timeout	A TDRE poll timed out mid-frame.

Precondition

Channel previously configured via ra8_sci_lin_init.

data is non-NULL and len is in 1..8.

Postcondition

On success, the data bytes and the checksum byte have been sent.

TDR holds the checksum (the final byte written).

Note

Thread safety: not thread-safe.

See also

ra8_sci_lin_read_response

ra8_sci_lin_checksum

Since

0.1.0

Definition at line 401 of file ra8_sci_lin.c.

References internal_lin_tx_buf(), k_ra8_err_invalid_arg, k_ra8_sci_lin_data_max, RA8_CHECK_NULL_PTR, RA8_RETURN_ON_ERROR, ra8_sci(), ra8_sci_lin_checksum(), ra8_sci_putc_polling(), and s_tag.

Referenced by lin_hil_send_frame().

ra8_sci_lin_wait_break()

ra8_err_t ra8_sci_lin_wait_break ( uint8_t channel )

nodiscard

Block until the responder detects a break field (XSR0.BFDF set).

Spins on XSR0.BFDF with a bounded budget; returns as soon as the break field is detected. On the host (RA8_OFF_TARGET) the poll runs against the programmable MMIO seam, so a test pre-stages BFDF or arms a timeout. Does not clear the flag – call ra8_sci_lin_clear_status before waiting for the next frame.

Parameters

[in]

channel

SCI channel number (0..9).

Returns

ra8_err_t error code.

Return values

k_ra8_ok	A break field was detected within the budget.
k_ra8_err_null_ptr	channel out of range.
k_ra8_err_hw_timeout	No break field detected within the budget.

Precondition

Channel previously configured as a responder via ra8_sci_lin_init.

IRQs masked or single-threaded receive context.

Postcondition

On success, XSR0.BFDF was observed set (still latched).

No data register is touched.

Note

Thread safety: not thread-safe.

See also

ra8_sci_lin_break_detected

ra8_sci_lin_clear_status

Since

0.1.0

Definition at line 379 of file ra8_sci_lin.c.

References k_ra8_hw_budget_long, k_ra8_sci_xsr0_bit_bfdf, RA8_CHECK_NULL_PTR, ra8_hw_wait_flag_set32(), ra8_sci(), s_tag, and r_sci_regs_t::XSR0.