32186 datasheet(731/1032 Pages) RENESAS

731 / 1032 page

CAN MODULE

13-121

32185/32186 Group Hardware Manual

Rev.1.10 REJ09B0235-0110 May 15, 07

13.5 Transmitting Data Frames

13.5.1 Data Frame Transmit Procedure

The following describes the procedure for transmitting data frames.

(1) Initializing CAN Message Slot Control Register

Initialize the CAN Message Slot Control Register for the slot to be transmitted by writing H’00 to the register.

(2) Confirming that transmission is idle

Read the CAN Message Slot Control Register that has been initialized and check the TRSTAT (Transmit/

Receive Status) bit to see that transmission/reception has stopped and remains idle. If this bit = "1," it

means that the CAN module is accessing the message slot. Therefore, wait until the bit is cleared to "0."

(3) Setting transmit data

Set the transmit ID and transmit data in the message slot.

(4) Setting CAN Frame Select Format Register

Set the corresponding bit in CAN Frame Select Format Register to "0" if the data is to be transmitted as a

standard frame, or "1" if the data is to be transmitted as an extended frame.

(5) Setting CAN Message Slot Control Register

Write H’80 (Note 1) to the CAN Message Slot Control Register to set the TR (Transmit Request) bit to "1."

Note 1: Always be sure to write H’80 when transmitting data frames.

32186 Datasheet(PDF) 731 Page - Renesas Technology Corp