SH7058 Datasheet, PDF (642/1130 Pages) Renesas Technology Corp – Renesas SuperHTM RISC engine

When these sources occur, the internal arbitration starts running to ensure that the highest priority
message is always transmitted first. The followings are examples set in figure 16.9.
1-1: When a TXPR bit is set while the CAN bus is idle, the internal arbitration starts running
immediately and the transmission is started.
2-1, 2-2: During this period (Tx-arbitration for frame-2), when any of the above 5 sources occurs,
the internal arbitration starts running and the next frame (Frame-2) to be transmitted is
scheduled.
3-1, 3-2: During this period (Rx matching), any internal arbitration is not allowed to run, but
scheduling is performed at the SOF of the next frame (Frame-2). If the transmit-
requested message has the highest priority, the transmission will be set for the Frame-3.
3-3, 3-4: This is the same case as 2-1, 2-2.
16.7.4 Message Transmission Cancellation Sequence
Figure 16.10 shows the sequence for canceling a message transmit request set by TXPR.
Rev. 3.0, 09/04, page 601 of 1086