Diagnostic Messages

Implementation related to diagnostic messages and packets is located in uds.messages sub-package.

UDS Message Implementation

Diagnostic messages implementation is divided into two parts:

UDS Message - storage for a temporary diagnostic message definition on the user side
UDS Message Record - storage for historic information of a diagnostic message that was either received or transmitted

UDS Message

UdsMessage class is meant to provide containers for diagnostic messages information. Once a diagnostic message object is created, it stores diagnostic message data that were provided by a user. One can use these objects to execute complex operations (provided in other subpackages) such as diagnostic messages transmission or segmentation.

All UdsMessage attributes are validated on each value change, therefore a user will face an exception if one tries to set an invalid (incompatible with the annotation) value to of these attributes.

Attributes implemented in UdsMessage class:

payload - settable
addressing - settable

Example code:

from uds.messages import UdsMessage, AddressingType

# example how to create an object
uds_message = UdsMessage(payload=[0x10, 0x03],
                         addressing=AddressingType.PHYSICAL)

# raw message attribute
print(uds_message.payload)
uds_message.payload = (0x62, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF)
print(uds_message.payload)
uds_message.payload = [0x3E, 0x80]
print(uds_message.payload)

# addressing attribute
print(uds_message.addressing)
uds_message.addressing = AddressingType.FUNCTIONAL
print(uds_message.addressing)
uds_message.addressing = AddressingType.PHYSICAL.value
print(uds_message.addressing)

UDS Message Record

UdsMessageRecord class is meant to provide container for historic information of diagnostic messages that were either transmitted or received. A user shall not create objects of this class in normal cases, but one would probably use them quite often as they are returned by other layers of uds package.

All UdsMessageRecord attributes are read only (they are set only once upon an object creation) as they store historic data and history cannot be changed (can’t it, right?). A user will face an exception if one tries to modify any attribute.

Attributes implemented in UdsMessageRecord class:

payload - readable
addressing - readable
direction - readable
packets_records - readable
transmission_start - readable
transmission_end - readable

UDS Packet Implementation

UDS packets implementation is divided into three parts:

UDS Packet Type - enums with Network Protocol Control Information (N_PCI) values definitions
UDS Packet - storages for a temporary Network Protocol Data Unit (N_PDU) definition on the user side
UDS Packet Record - storages for historic information of a Network Protocol Data Unit (N_PDU) that was either received or transmitted

UDS Packet Type

UDS packet types are supposed to be understood as values of Network Protocol Control Information (N_PCI). Supported values of UDS packet types are defined in specially designed for this purpose enum classes.

Enum classes that implements UDS packet types:

AbstractUdsPacketType

AbstractUdsPacketType

AbstractUdsPacketType class is an empty enum that is a parent class for all concrete UDS packet types enum classes. It provides common API and values restriction (UDS packet type values must be 4-bit integer) for all children classes.

A user shall not use AbstractUdsPacketType directly, but one is able (and encouraged) to use AbstractUdsPacketType implementation with any of its children classes.

Methods implemented in AbstractUdsPacketType class:

UDS Packet

UDS packets differs for each communication bus, therefore multiple classes implementing them are defined. Each UDS packet class provides containers for Network Protocol Data Unit (N_PDU) information that are specific for a communication bus for which this class is relevant. Objects of UDS packet classes might be used to execute complex operations (provided in other subpackages) such as packets transmission or desegmentation.

Implemented UDS packet classes:

AbstractUdsPacket

AbstractUdsPacket

AbstractUdsPacket class contains common implementation and provides common API for all UDS Packet classes as they are inheriting after AbstractUdsPacket class.

A user shall not use AbstractUdsPacket directly, but one is able (and encouraged) to use AbstractUdsPacket implementation with any of its children classes.

Properties implemented in AbstractUdsPacket class:

raw_data - settable
addressing - settable
packet_type - readable

UDS Packet Record

UDS packet record is a container that stores historic information of UDS packet (N_PDU) that was either received or transmitted. UDS packets differs for each communication bus, therefore multiple classes implementing UDS packet records are defined.

A user shall not create objects of UDS packet record classes in normal cases, but one would probably use them quite often as they are returned by other layers of uds package.

Implemented UDS packet record classes:

AbstractUdsPacketRecord

AbstractUdsPacketRecord

AbstractUdsPacketRecord class contains common implementation and provides common API for all UDS Packet classes as they are inheriting after AbstractUdsPacketRecord class.

A user shall not use AbstractUdsPacketRecord directly, but one is able (and encouraged) to use AbstractUdsPacketRecord implementation with any of its children classes.

Properties implemented in AbstractUdsPacketRecord class:

frame - readable
direction - readable
packet_type - readable
raw_data - readable and abstract (bus specific)
addressing - readable and abstract (bus specific)
transmission_time - readable and abstract (bus specific)

UDS Messages Data

Implementation of data parameters that are defined by UDS specification.

UDS data parameters:

Service Identifiers - are implemented by:
Negative Response Codes

Service Identifiers

POSSIBLE_REQUEST_SIDS

POSSIBLE_REQUEST_SIDS is a set with all possible values of Service Identifier data parameter in a request message.

RequestSID

Enum RequestSID contains definitions of request Service Identifiers values.

Methods implemented in RequestSID class:

POSSIBLE_RESPONSE_SIDS

POSSIBLE_RESPONSE_SIDS is a set with all possible values of Service Identifier data parameter in a response message.

ResponseSID

Enum ResponseSID contains definitions of response Service Identifiers values.

Methods implemented in ResponseSID class:

Negative Response Codes

Enum NRC contains definitions of all common (defined by ISO 14229) Negative Response Codes values.

Methods implemented in NRC class:

Transmission Attributes

Attributes that describes UDS communication:

Addressing - enum with UDS communication models
Transmission Direction - enum with communication directions

Addressing

Enum AddressingType contains definitions of addressing values that determines UDS communication model:

PHYSICAL - direct one to one communication (physical addressing)
FUNCTIONAL - one to many communication (functional addressing)

Methods implemented in AddressingType class:

Transmission Direction

Enum TransmissionDirection contains definitions of communication directions:

RECEIVED - incoming
TRANSMITTED - outcoming

Methods implemented in TransmissionDirection class: