32186 datasheet(732/1032 Pages) RENESAS

732 / 1032 page

CAN MODULE

13-122

32185/32186 Group Hardware Manual

Rev.1.10 REJ09B0235-0110 May 15, 07

13.5 Transmitting Data Frames

Data frame transmit procedure

Initialize CAN Message

Slot Control Register

Set ID and data in the

CAN message slot

Set the CAN Frame

Format Select Register

Set CAN Message Slot

Control Register

End of setting

Write H'00

Select standard ID or extended ID

Write H'80 (transmit request)

Read CAN Message Slot

Control Register

TRSTAT bit = 0

YES

Confirm that transmission

and reception are idle

Figure 13.5.1 Data Frame Transmit Procedure

13.5.2 Data Frame Transmit Operation

The following describes data frame transmit operation. The operations described below are automatically per-

formed in hardware.

(1) Selecting a transmit frame

The CAN module checks slots which have transmit requests (including remote frame transmit slots) every

intermission to determine the frame to transmit. If two or more transmit slots exist, frames are transmitted in

order of slot numbers beginning with the smallest.

(2) Transmitting a data frame

After determining the transmit slot, the CAN module sets the corresponding CAN Message Slot Control

(3) If lost in CAN bus arbitration or a CAN bus error occurs

If the CAN module lost in CAN bus arbitration or a CAN bus error occurs in the middle of transmission, the

CAN module clears the CAN Message Slot Control Register’s TRSTAT (Transmit/Receive Status) bit to "0."

If the CAN module requested a transmit abort, the transmit abort is accepted and the message slot is

enabled for write.

32186 Datasheet(PDF) 732 Page - Renesas Technology Corp