SH7261 datasheet(849/1348 Pages) RENESAS

849 / 1348 page

Section 19 Controller Area Network (RCAN-ET) [R5S72611] [R5S72613]

Rev. 2.00 Sep. 07, 2007 Page 817 of 1312

REJ09B0320-0200

19.3.2

Message Control Field

STDID[10:0]: These bits set the identifier (standard identifier) of data frames and remote frames.

EXTID[17:0]: These bits set the identifier (extended identifier) of data frames and remote frames.

RTR (Remote Transmission Request bit): Used to distinguish between data frames and remote

frames. This bit is overwritten by received CAN Frames depending on Data Frames or Remote

Frames.

Important: Please note that, when ATX bit is set with the setting MBC = B'001, the RTR bit will

never be set. When a Remote Frame is received, the CPU can be notified by the corresponding

RFPR set or IRR[2] (Remote Frame Request Interrupt), however, as RCAN-ET needs to transmit

the current message as a Data Frame, the RTR bit remains unchanged. In case of overrun

condition, the message received is discarded. Consequently, when a remote frame is causing

overrun (UMSR is set) into a Mailbox configured with ATX = 1/NMC = 0, the transmission of the

corresponding data frame is not carried out.

Important: In order to support automatic answer to remote frame when MBC = B'001 is used and

ATX = 1 the RTR flag must be programmed to zero to allow data frame to be transmitted.

Note:

when a Mailbox is configured to send a remote frame request the DLC used for

transmission is the one stored into the Mailbox.

RTR

Description

Data frame

Remote frame

IDE (Identifier Extension bit): Used to distinguish between the standard format and extended

format of CAN data frames and remote frames.

IDE

Description

Standard format

Extended format

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