Contents
What is standby mode in CAN transceiver?
In Standby mode, the transceiver is not able to transmit or correctly receive data via the bus lines. The transmitter and Normal-mode receiver blocks are switched off to reduce supply current, and only a low-power differential receiver monitors the bus lines for activity.
What is a fault tolerant transceiver?
The TJA1055T is an advanced fault-tolerant CAN transceiver primarily intended for low-speed applications up to 125kBd in passenger cars. Besides the differential receive and transmit capability the transceiver provides single-wire transmitter and/or receiver in error conditions.
CAN transceiver modes?
TI’s CAN and LIN transceivers are designed with all of this in mind, allowing for normal, standby, silent, and sleep modes depending on the device. All of these modes allow the system to be designed in a way that is fully functioning but power-conservative.
CAN dominant time out?
The CAN transceivers provide a dominant timeout function that prevents erroneous CAN controllers from clamping the bus to a dominant level if the TXD input is held low for greater than 1ms. The MAX13050/MAX13052 provide a SPLIT pin used to stabilize the recessive common-mode voltage.
CAN bus silence?
Silent mode means the interface only listens to the CAN bus. This means the unit does not even provide an ACK frame when a message is placed on the CAN bus correctly.
CAN transceiver voltage levels?
Standard CAN bus transceivers operate over a limited common mode voltage range that extends from −2V to +7V. In commercial or industrial environments, ground faults, noise, and other electrical interference can induce common mode voltages that greatly exceed these limits.
CAN high and low shorted together?
There are two different communication lines used in a CAN bus, the CANH and CANL, high and low respectively. These two lines have multiple ways that they can be shorted. They can be shorted to ground, shorted to VCC, or shorted together.
CAN transceiver silent mode?
Silent mode can be used to prevent a faulty CAN controller from disrupting all network communications. A LOW level on pin EN of TJA1051T/E selects Off mode. In Off mode the entire transceiver is disabled, allowing the microcontroller to save power when CAN communication is not required.
How does a CAN transceiver work in a circuit?
A logical TxD LOW or 0 bit is transformed to a dominant state. A logical TxD HIGH or 1 bit is transformed to a recessive state. This should be enough for the first understanding! CANH and CANL output transistors are open ( high impedant ). The recessive voltage level of CANH and CANL = VDD / 2 ≈ 2.5 V is created by the following circuit part.
How does a CAN transceiver work high impedant?
CANH and CANL output transistors are open ( high impedant ). The recessive voltage level of CANH and CANL = VDD / 2 ≈ 2.5 V is created by the following circuit part. CANH and CANL output transistors are closed. Did I miss something or is my calculation valid (just for basic understanding 🙂 )?
How does a CAN transceiver work in the dominant state?
In the recessive state: CANH and CANL should be at the same voltage level (≈ 2.5 V). In the dominant state: CANH and CANL should have a high voltage difference (≈ 2 V). There must be at least one termination resistor of ≈ 120 Ω. A logical TxD LOW or 0 bit is transformed to a dominant state.
How to find a node with a faulty transceiver?
To find the node with a faulty transceiver please test the CAN transceiver resistance (see section 1.4). The shield of the CAN network has to be grounded at only one location. This test will indicate if the shielding is grounded in several places. To test it, please: Disconnect the shield wire (Shield) from the ground.