ST10F272Z2_08 datasheet(131/189 Pages) STMICROELECTRONICS

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ST10F272Z2

Known limitations

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24.2

Concurrent transmission requests in DAR-mode (C-CAN

module)

Description

When the C-CAN module is configured to operate in DAR-mode (Disable Automatic

Retransmission) and the host requests the transmission of several messages at the same

time, only two of these messages are transmitted. For all other requested transmit

messages, the TxRqst bits are reset but no transmission starts, NewDat and IntPnd are kept

unchanged. For the two messages which are transmitted, the TxRqst and NewDat bits are

reset and IntPnd is set if it has been enabled by TxIE.

The normal operation mode (DAR = 0) is not affected by this phenomenon.

Workaround

The DAR-mode is intended to support time triggered operation (TTCAN level 1), accepting

the transmission of a message only in its dedicated time window. It is an error to request the

transmission of several messages at the same time. So no workaround is necessary for

TTCAN applications.

The progress of a requested transmission can be monitored by checking the message

object’s TxRqst and NewDat [optionally IntPnd] bits. In DAR-Mode, when a message

transmission has failed either because the transmission was disturbed or because it has not

started, it is necessary to request the message transmission again.

For details on DAR mode and message control registers, refer to user manual UM0409.

ST10F272Z2 数据表(PDF) 131 Page - STMicroelectronics