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Automotive Interview Questions
moncler outlet jackets Answer: 1. CAN is a multi master broadcast serial bus standard for connecting electronic monlcer down jackets control unit (ECUs). moncler outlet jackets
moncler outlet sale 2. Controller area network (CAN or CAN bus) is a vehicle bus standard designed to allow microcontrollers a devices to communicate with each other within a vehicle without a host computer. moncler outlet sale
3. CAN is cheap moncler outlet a message based protocol, designed specifically for automotive applications but now also used in other areas such as industrial automation and medical equipment.
cheap moncler jackets 4. The Controller Area Network (CAN) bus is a serial asynchronous bus used in instrumentation applications for industries such as cheap moncler jackets automobiles. cheap moncler jackets
moncler outlet store Easy to implement, changes, too. Why CAN is having 120 ohms at each end? moncler outlet store
cheap moncler jackets sale Answer: To minimize the reflection reference, to reduce noise. To ensure that reflection does not cause communication failure, the transmission line must be terminated. cheap moncler jackets sale
cheap moncler coats 4. Why CAN is message oriented protocol? cheap moncler coats
moncler outlet Answer: CAN protocol is a message based protocol https://www.thebeastmark.com , not an address based protocol. This means that messages are not transmitted from one node to another node based on addresses. Embedded in the CAN message itself is the moncler mens jackets priority and the contents of the data being transmitted. All moncler sale nodes in the system receive every message transmitted on the bus (and will acknowledge if the message was properly received). It is up to each node in the system to decide whether the message received should be immediately discarded or kept to be processed. A single message can be destined for one particular node to receive, or many nodes based on the way the network and system are designed. For example, an automotive airbag sensor can be connected via CAN to a safety system router node only. This router node takes in other safety system information and routes it to all other nodes on the safety system network. Then all the other nodes on the safety system network can receive the latest airbag sensor information from the router at the same cheap moncler sale time, acknowledge if the message was received properly, and decide whether to utilize this information or discard it. moncler outlet
Answer: CSMA/CD AMP (Arbitration on Message Priority)
moncler sale Two bus nodes have got a transmission request. The bus access method is CSMA/CD AMP (Carrier Sense Multiple Access with Collision Detection and Arbitration on Message Priority). According to this algorithm both network nodes wait until the bus is free (Carrier Sense). In that case the bus is free both nodes transmit their dominant start bit (Multiple Access). Every bus node reads back bit by bit from the bus during the complete message and compares the transmitted value with the received value. As long as the bits are identical from both transmitters nothing happens. The first time there was a cheap moncler coats difference in this example the 7th bit of the message the arbitration process takes place: Node A transmits a dominant level, node B transmits a recessive level. The recessive level will be overwritten by the dominant level. This is detected by node B because the transmitted value is not equal to the moncler outlet received value (Collision Detection). At this point of time node B has lost the arbitration, stops the transmission of any further bit immediately and cheap moncler switches to receive mode, because the message that has won the arbitration must possibly be processed by this node (Arbitration on Message Priority) moncler sale
For example, consider three CAN devices each trying to transmit messages:
moncler outlet uk Device 1 address 433 (decimal or 00110110001 binary) moncler outlet uk
moncler jackets outlet Device 2 address 154 (00010011010) moncler jackets outlet
Device 3 address 187 (00010111011)
Assuming all three see the bus is idle and begin transmitting at the same time, this is how the arbitration works out. All three devices will drive the bus to a moncler sale outlet dominant state for the start of frame (SOF) and the two most significant bits of each message identifier. Each device will monitor the bus and determine success. When they write bit 8 of the message ID, the device writing message ID 433 will notice that the bus is in the dominant state when it was trying to let it be recessive, buy moncler jackets so it will assume a collision and give up for now. The remaining devices will continue writing bits until bit 5, then the device writing message ID 187 will notice a collision and abort transmission. This leaves the device writing message ID 154 remaining. It will continue writing bits on the bus until complete or an error is detected. Notice that this method of arbitration will always cause the lowest numerical value message ID moncler outlet sale to have priority. This same method of bit wise arbitration and prioritization applies to the 18 bit extension in the extended format as well.
moncler jacket sale 9. If master sends 764 and Slave sends 744 which will get the arbitration? moncler jacket sale
moncler outlet online Answer: Starts from MSB, first nibble is same Cheap Moncler Jackets , Master sends 7, slaves also sends 7 the message with more dominant bits will gain the arbitration, lowest the message identifier higher the priority. moncler outlet online
10. Standard CAN and Extended CAN difference?
moncler sale outlet Answer: Number of identifiers can be accommodated for standard frame are 2power11. moncler sale outlet
moncler factory outlet Number of identifiers more compare to base frame, for extended frame are 2power29. moncler factory outlet
cheap moncler outlet IDE bit 1 for extended frame. cheap moncler outlet
IDE bit 0 for Standard frame.
Answer: CAN uses a Non Return to Zero protocol, NRZ 5, with bit stuffing. The idea behind bit stuffing is to provide a guaranteed edge on the signal so the receiver can resynchronize with the transmitter before minor clock discrepancies between the two nodes can cause a problem. With NRZ 5 the transmitter transmits at most five consecutive bits with the same value. After five bits with the same value (zero or one), the transmitter inserts a stuff bit with moncler outlet store the opposite state.