SH7055S Datasheet, PDF(598/1002 Page) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7000 Series

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SH7055S Datasheet, PDF (598/1002 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7000 Series

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1 Mb/s =

20 MHz

2 Ã (0 + 1) Ã (3 + 4 + 3)

fCLK

BRP

TSEG1

TSEG2

Set Values

40 MHz/2

0 (B'000000)

4 (B'0100)

3 (B'011)

Actual Values

â

System clock Ã 2

5TQ

4TQ

Mailbox Transmit/Receive Settings: HCAN0 and HCAN1 each have 16 mailboxes. Mailbox 0 is

receive-only, while mailboxes 1 to 15 can be set for transmission or reception. Mailboxes that can

be set for transmission or reception must be designated either for transmission use or for reception

use before communication begins. The Initial status of mailboxes 1 to 15 is for transmission

(while mailbox 0 is for reception only). Mailbox transmit/receive settings are not initialized by a

software reset.

â¢ Setting for transmission

Transmit mailbox setting (mailboxes 1 to 15)

Clearing a bit to 0 in the mailbox configuration register (MBCR) designates the corresponding

mailbox for transmission use. After a reset, mailboxes are initialized for transmission use, so

this setting is not necessary.

â¢ Setting for reception

Transmit/receive mailbox setting (mailboxes 1 to 15)

Setting a bit to 1 in the mailbox configuration register (MBCR) designates the corresponding

mailbox for reception use. When setting mailboxes for reception, to improve message

transmission efficiency, high-priority messages should be set in low-to-high mailbox order

(priority order: mailbox 1 (MCx[1]) > mailbox 15 (MCx[15])).

â¢ Receive-only mailbox (mailbox 0)

No setting is necessary, as this mailbox is always used for reception.

Mailbox (Message Control/Data (MCx[x], MDx[x]) Initial Settings: After power is supplied,

all registers and RAM (message control/data, control registers, status registers, etc.) are initialized.

Message control/data (MCx[x], MDx[x]) only are in RAM, and so their values are undefined.

Initial values must therefore be set in all the mailboxes (by writing 0s or 1s).

Setting the Message Transmission Method: Either of the following message transmission

methods can be selected with the message transmission method bit (MCR2) in the master control

register (MCR):

1. Transmission order determined by message identifier priority

2. Transmission order determined by mailbox number priority

Rev.2.0, 07/03, page 560 of 960

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