Lin — Requirements

Normative

Defines what a conformant LIN driver MUST do. Requirements are clustered by severity — expand a cluster below. Keywords per Requirement Keywords; conformance per Conformance. Requirements do not carry individual status — the set-level status applies to all of them. Signatures, error codes, and configuration properties are in the API Reference, Errors, and Configuration Reference pages. Cross-module rules (types, error model, naming, memory mapping) are in General.

Mandatory (MUST) - 19 Requirements

The conformance contract — an implementation MUST satisfy every requirement here.

Lifecycle and channel state

CHI-LIN-MUST-01 — ISO 17987 compliance

The driver MUST implement LIN responder behavior in conformance with ISO 17987.

CHI-LIN-MUST-02 — Driver lifecycle

The driver MUST power up in LIN_DRV_STATE_UNINIT. Lin_Init MUST move it to LIN_DRV_STATE_INIT and leave every channel in LIN_CH_STATE_SLEEP; Lin_DeInit MUST abort any ongoing transfer and return the driver to LIN_DRV_STATE_UNINIT.

CHI-LIN-MUST-03 — Channel power-state transitions

Each channel MUST follow the state machine in Concepts. Lin_Wakeup and Lin_WakeupInternal MUST move a channel from SLEEP to OPERATIONAL; Lin_GoToSleepInternal MUST move it from OPERATIONAL to SLEEP. Only in OPERATIONAL does the channel participate in bus traffic.

CHI-LIN-MUST-04 — Wakeup-call state restriction

Lin_Wakeup (which transmits a wakeup pulse) MUST be rejected with a development error when the channel is not in SLEEP.

Frame handling

CHI-LIN-MUST-05 — Header reception

In OPERATIONAL, the driver MUST receive each LIN header (break field, sync byte, and protected identifier) and report it to the upper layer via LinIf_OnHeader.

CHI-LIN-MUST-06 — Response transaction

Per the reaction returned by LinIf_OnHeader, the driver MUST transmit the response (LIN_REACTION_TX), receive it (LIN_REACTION_RX), or ignore it (LIN_REACTION_IGNORE), applying the requested checksum model (LIN_CS_CLASSIC / LIN_CS_ENHANCED) and data length.

CHI-LIN-MUST-07 — PID evaluation

The driver MUST evaluate the received protected identifier and forward it to the upper layer. Where the hardware cannot verify PID parity, the driver MUST NOT verify it in software (it MAY report LIN_ERR_PID_PARITY only where the hardware detects it).

CHI-LIN-MUST-08 — Frame data byte mapping

The driver MUST map response data bytes byte 0 first between the bus and the SDU buffer.

CHI-LIN-MUST-09 — Data consistency

Data passed to LinIf_OnReception and the sduPtr buffer in LinIf_OnHeader MUST be valid only for the duration of the call. The caller MUST consume it before returning; the driver MUST NOT rely on the buffer after the callback returns.

CHI-LIN-MUST-10 — Response sequence ordering

The driver MUST process a header and its response in order, and MUST set up reception of the next header before or when reporting completion of the current response.

Wakeup and events

CHI-LIN-MUST-11 — Sleep-state wakeup detection

In SLEEP with wakeup detection enabled, the driver MUST detect a bus wakeup pulse and report it via LinIf_OnWakeup (including a pulse the node transmitted itself).

CHI-LIN-MUST-12 — Event handling mode

For each channel, event handling MUST be configurable as interrupt or polling. In interrupt mode Lin_Init MUST enable the interrupt and Lin_Interrupt MUST service it; in polling mode the interrupt MUST be disabled and Lin_PollFunction MUST service the events.

CHI-LIN-MUST-13 — Upper-layer notifications

Whichever mode is configured, the driver MUST invoke the upper-layer callbacks for the corresponding events: LinIf_OnHeader (header received), LinIf_OnReception (response received), LinIf_OnTransmission (response sent), LinIf_OnError (bus error), and LinIf_OnWakeup (wakeup detected).

API, types, and errors

CHI-LIN-MUST-14 — LIN API surface and behavior

The driver MUST provide Lin_Init, Lin_DeInit, Lin_Wakeup, Lin_WakeupInternal, Lin_GoToSleepInternal, Lin_PollFunction, and the interrupt handler with the behavior described in API Reference. Lin_Init MUST accept only NULL_PTR as configPtr.

CHI-LIN-MUST-15 — Type contract

The driver MUST provide the LIN types Lin_ConfigType, Lin_PduInfoType, Lin_PidType, Lin_DlType, Lin_CsType, Lin_ReactionType, and Lin_ErrorType as defined in API Reference, and MUST use the shared type system from General (CHI-GEN-MUST-09).

CHI-LIN-MUST-16 — Development error definitions

The driver MUST define the development errors LIN_DEVERR_UNINIT, LIN_DEVERR_PARAM_CHANNELID, LIN_DEVERR_PARAM_POINTER, and LIN_DEVERR_INVALID_CH_STATE.

CHI-LIN-MUST-17 — Development error detection

When development error reporting is enabled, each API MUST detect the conditions listed in Errors and report them via LogM_Report (CHI-GEN-MUST-10).

CHI-LIN-MUST-18 — Upper-layer callback contract

The driver MUST call the upper-layer interfaces LinIf_OnHeader, LinIf_OnReception, LinIf_OnTransmission, LinIf_OnError, and LinIf_OnWakeup with the parameters and at the points defined in API Reference.

Configuration

CHI-LIN-MUST-19 — Configuration model

The driver MUST support the configuration model in Configuration Reference — a General section and a ConfigSet with one or more Channel entries (channel_id, hw_channel, clock_divider, event_handling_mode, enable_wakeup_detection) — following the common model in General (CHI-GEN-MUST-12).

Recommended (SHOULD) - 2 Requirements

Strongly advised; an implementation that deviates should understand the implications.

Power and wakeup

CHI-LIN-SHOULD-01 — Low-power mode in sleep

When a channel enters SLEEP, the driver SHOULD place the LIN hardware in a low-power mode where the hardware supports it.

CHI-LIN-SHOULD-02 — Hardware setup around the wakeup pulse

After transmitting a wakeup pulse (Lin_Wakeup) or completing wakeup handling, the driver SHOULD apply any hardware setting change needed to enable header reception before the first header arrives.