Extended Addressing

Overview

Extended Addressing is an ISO 15765-2 addressing format in which the network address information is split between the 11-bit CAN identifier and an Address Extension (AE) byte carried in payload byte 0.

For the definition of the addressing format, the source/target semantics, the frame structure and the functional-addressing rules, refer to ISO 15765-2. This page documents only what is specific to the OpenBSW implementation.

Implementation:

• DoCanExtendedAddressing

• DoCanExtendedAddressingFilter (table-based)

Note

All examples use the project configuration: tester transport id 0xF4 (EXTENDED_ADDRESSING_TESTER_ID), ECU 0x2A (LOGICAL_ADDRESS), request CAN id 0x600, response CAN id 0x601.

Data Link Address Representation

To use a single internal address type, the CAN identifier and Address Extension are combined into one packed data-link address (AE in the high 8 bits, CAN id in the low 11 bits):

pack(canId, addressExtension)   // build
canIdOf(address)                // decompose
addressExtensionOf(address)     // decompose

Reported address format: DoCanAddressFormat::Extended.

Codec Preset

DoCanFrameCodecConfigPresets::EA_PADDED_CLASSIC
{
   {8U, 8U}, {8U, 8U}, {8U, 8U}, {8U, 8U}, // SF / FF / CF / FC
   0xCCU,    // filler
   1U        // offset: byte 0 reserved for the Address Extension (N_TA)
}

The offset remains 1U (protocol data begins at payload byte 1).

Address Entries

The filter is configured with a list of { canId, transportId } entries, each associating a CAN identifier with the transport address of the node that transmits on it. Entries must be ascending by CAN id (duplicates allowed); init() asserts this ordering.

Project configuration (EXTENDED_ADDRESSING_ADDRESSES):

{
   { 0x600U, EXTENDED_ADDRESSING_TESTER_ID },   // tester 0xF4 -> request  0x600
   { 0x601U, LOGICAL_ADDRESS },                 // ECU 0x2A    -> response 0x601
   { 0x601U, FUNCTIONAL_ALL_ISO14229 }          // functional entry
}

The functional entry deliberately reuses 0x601 (the ECU’s real response id) so any Flow Control for a multi-frame functional exchange is emitted on the correct CAN id. The physical and functional entries on 0x601 are disambiguated by the Address Extension byte, not the CAN id. Functional addresses are passed to init() as a non-owning span (EXTENDED_ADDRESSING_FUNCTIONAL_ADDRESSES = { FUNCTIONAL_ALL_ISO14229 }).

Functional handling follows ISO 15765-2: single-frame only. A functional target causes getReceptionParameters() to report INVALID_ADDRESS, so DoCanReceiver rejects a multi-frame functional request.

Reception / Transmission Mapping

• decodeReceptionAddress() returns pack(canId, payload[0]).

• getReceptionParameters() resolves source by CAN id and target by AE, then builds the transport pair (sourceEntry.transportId, targetId).

• encodeTransmissionAddress() sets canId = canIdOf(address) and payload[0] = addressExtensionOf(address).

• getTransmissionParameters() looks up source/target entries by transport id; returns nullptr if either is not configured.

Example (request, tester 0xF4 -> ECU 0x2A):

0xF4 -> 0x600 (source entry), 0x2A -> 0x601 (target entry)
TX = pack(0x601, 0xF4)   RX = pack(0x600, 0x2A)

Filter and Layer Integration

DoCanExtendedAddressingFilter implements IDoCanAddressConverter and can::BitFieldFilter. Each configured CAN id is registered via BitFieldFilter::add(canId) in init(); frame admission is delegated to BitFieldFilter::match().

There is no composite converter. The filter is the IDoCanAddressConverter of a dedicated Extended transport layer aggregated by DoCanMultiAddressingTransportLayer:

_multiAddressingTransportLayer.bind(
    normalAddressingLayer,
    extendedAddressingLayer,      // backed by _extendedAddressingFilter
    rangeExtendedAddressingLayer,
    normalFixedAddressingLayer);

On transmission, routing to this layer is by tester id (EXTENDED_ADDRESSING_TESTER_ID). formatDataLinkAddress() prints 0x<canId>/0x<ae> in lowercase (e.g. 0x601/0xf4).

init() arguments:

• addressEntries - the {canId, transportId} table (non-empty, ascending).

• functionalAddresses - non-owning span (may be empty).

• codec - EA_PADDED_CLASSIC.

Both spans are non-owning views; the backing arrays must outlive the filter and are therefore file-local statics.

Implementation Invariants

• Address Extension occupies payload byte 0; protocol data begins at byte 1.

• EA_PADDED_CLASSIC keeps offset 1U.

• Packed addresses carry both CAN id and Address Extension.

• Address entries stay ascending by CAN id (duplicates allowed).

• Reception and transmission mappings remain reversible.

• Filter admission stays delegated to BitFieldFilter.

• Address format stays DoCanAddressFormat::Extended.

• The filter is bound as the Extended layer of DoCanMultiAddressingTransportLayer.