AUTOSAR CAN Interface Layer | CAN IF |Functionality of CAN Interface layer and CAN Driver

Software Systems

3 Jun 202205:29

Summary

TLDRThis video script explains the CAN transport layer and its role in handling data beyond 8 bytes, utilizing CAN TP for segmentation and reassembling. It discusses the CAN interface layer's interaction with the CAN driver, emphasizing the abstraction of hardware details. The script also highlights the importance of the CAN driver in configuring multiple CAN controllers within an ECU for efficient data transfer, providing APIs for communication between layers.

Takeaways

📏 The CAN frame size is 8 bytes, and data exceeding this size is handled by the CAN Transport Protocol (CAN TP).
🔄 CAN TP is responsible for segmenting and reassembling data that exceeds the 8-byte limit before transmitting it to the CAN interface.
🛠️ Configuration of CAN TP or direct CAN interface layer can be adjusted based on the size of the PDU (Protocol Data Unit).
🔄 If a video with a size more than 8 bytes is involved, CAN TP assembles the messages.
🌐 The CAN interface layer handles the communication perspective, managing multiple groups of PDUs and their transmission or reception.
🎯 The ultimate goal of the CAN interface layer is to push PDUs into the hardware unit, which involves setting registers of memory and converting PDUs into CAN high and CAN low signals.
🔌 The CAN interface layer works in conjunction with the CAN MCAL (Microcontroller Abstraction Layer) driver to manage multiple CAN controllers within an ECU (Electronic Control Unit).
📍 The CAN interface module interacts with the CAN driver, using hardware addresses provided by the driver to map PDUs.
🔩 The CAN driver is responsible for pushing PDUs to the hardware object, having the physical address of the CAN controller register.
🔄 The transmission and reception of hardware addresses are managed by the CAN driver, abstracting the CAN interface layer from direct hardware interaction.
🛠️ The BSW (Basic Software) stack configuration is often pre-configured in the CAN interface layer, allowing for easier management of the CAN driver and interface.

Q & A

What is the size of a CAN frame?
-The size of a CAN frame is 8 bytes.
What happens when the data size exceeds the 8th byte in a CAN frame?
-When the data size exceeds the 8th byte, it is forwarded to the CAN Transport Protocol (CAN TP) for segmentation and reassembling.
What is the primary responsibility of the CAN TP?
-The primary responsibility of the CAN TP is to segment the data into smaller pieces that fit into CAN frames and then reassemble them at the receiving end.
How does the CAN TP handle data that is more than 8 bytes?
-The CAN TP assembles the messages and sends them to the CAN interface layer for transmission.
What is the role of the CAN interface layer?
-The CAN interface layer is responsible for pushing the PDU into the hardware unit, converting the PDUs into CAN high and CAN low signals, and interfacing with the CAN driver.
What does the CAN interface layer do in terms of hardware interaction?
-The CAN interface layer works in tandem with the CAN driver to map the hardware address of the CAN controller to the PDUs and push the data to the hardware interface.
How does the CAN interface layer abstract from the CAN controller?
-The CAN interface layer abstracts from the CAN controller by taking the hardware address from the CAN driver and mapping it to the PDUs, allowing changes in the CAN controller without affecting the interface layer.
What is the function of the CAN driver?
-The CAN driver is responsible for pushing the PDUs to the hardware object, managing the physical address of the CAN controller register, and handling the transmission and reception of data.
How is the mapping of hardware addresses done in the CAN driver?
-The CAN driver maps the hardware addresses by reading the addresses and mapping them to the PDUs, allowing the CAN interface layer to interact with the hardware without worrying about the specific hardware objects.
What is the lowest layer in the CAN communication stack?
-The CAN driver is the lowest layer in the CAN communication stack, interacting only with the CAN interface layer and providing interfaces and APIs for communication.
What is the purpose of the BSW layer in the context of CAN communication?
-The BSW layer, or Basic Software layer, is responsible for the configuration of the CAN interface layer and may include pre-configured layers from the semiconductor vendor, ensuring proper data transfer and communication between layers.