E520.14 Datasheet, PDF(19/41 Page) ELMOS Semiconductor AG – Provides four HS-CAN physical interfaces

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E520.14 Datasheet, PDF (19/41 Pages) ELMOS Semiconductor AG – Provides four HS-CAN physical interfaces

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Quad CAN transceiver

PRODUCTION DATA â FEB 4, 2014

E520.14

4.3.2 HS-CAN Failure Detection and Recovery

All CAN related local or bus failures are signaled in register CAN_STAT.

There are two possibilities to recover the normal operation after a failure:

â¢ Setting CAN_CFG.RC = H via SPI

â¢ RXD is dominant while TXD is recessive

TXD Dominant clamping failure

This failure can only be detected if the transmitter is enabled, e.g. bit TR in register CAN_CFG ist set to high. If TXD

is clamped dominant for longer than tCAN,TXD,DOM the transmitter is disabled and a failure flag is set.

RXD dominant clamping failure

This failure can be detected if the transmitter is enabled, which means bit RC in register CAN_CFG is set. If RXD is

clamped low for 4 consecutive CAN cycles the transmitter is disabled and a failure flag is set.

RXD recessive clamping failure

This failure can be detected the transmitter is enabled, which means bit RC in register CAN_CFG is set. If RXD is

clamped recessive level for 4 consecutive CAN cylces the transmitter is disabled and a failure flag is set.

BUS dominant clamping failure

This failure can be detected if the transmitter is enabled, which means bit RC in register CAN_CFG is set. If CAN is

clamped dominant for longer than tCAN,BUS,DOM a failure flag is set. The transmitter is not disabled.

TXD to RXD clamping failure

This failure can only be detected if the transmitter is enabled. Pin TXD is set to low that CAN becomes dominant.

Afterwards pin RXD is set to low too controlled by the receiver. In case of error condition present pin TXD can not

be released to high because the driver of RXD is much stronger. If TXD is clamped dominant for longer than

tCAN,TXD,DOM the transmitter is disabled and a failure flag is set.

OT failure

If OT occurs the transmitter is disabled and a failure flag is set.

The transmitter is enabled again if the temperature falls below its threshold and the conditions for the failure

recovery are present.

CANH to GND clamping failure

This failure can be detected if transmitter is enabled, e.g. bit TR and BFEN in register CAN_CFG are set. If the

short is present for 4 consecutive CAN cycles on TXD with bit time â¥ tCAN,TXD,SHORT a failure flag is set. The transmitter

is not disabled.

CANL to GND clamping failure

This failure can be detected if transmitter is enabled, e.g. bit TR and BFEN in register CAN_CFG are set. If the

short is present for 4 consecutive CAN cycles on TXD with bit time â¥ tCAN,TXD,SHORT a failure flag is set. The transmitter

is not disabled.

CANH to VCC/VS clamping failure

This failure can be detected if transmitter is enabled, e.g. bit TR and BFEN in register CAN_CFG are set. If the

short is present for 4 consecutive CAN cycles on TXD with bit time â¥ tCAN,TXD,SHORT a failure flag is set. The transmitter

is not disabled.

CANL to VCC/VS clamping failure

This failure can be detected if transmitter is enabled, e.g. bit TR and BFEN in register CAN_CFG are set. If the

short is present for 4 consecutive CAN cycles on TXD with bit time â¥ tCAN,TXD,SHORT a failure flag is set. The transmitter

is not disabled.

Elmos Semiconductor AG reserves the right to change the detail specifications as may be required to permit improvements in the design of its products.

Elmos Semiconductor AG

Data Sheet 19 / 41

QM-No.: 25DS2014E.02

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