HD64F36034 datasheet(372/592 Pages) RENESAS

372 / 592 page

Section 15 Controller Area Network for Tiny (TinyCAN)

Rev. 4.00 Mar. 15, 2006 Page 340 of 556

REJ09B0026-0400

15.5.5

Reconfiguring Mailbox

A Mailbox can be reconfigured using the following procedure:

Changing CAN-ID and MBCR of Transmit Mailbox: Make sure that the bit corresponding to

the Mailbox in TXPR is not set to 1. The identifier of the transmit Mailbox and corresponding

MBCR bit can be changed at any time. If both of them need to be changed, change the identifier

first, clear RXPR and RFPR to 0, and then change MBCR.

Changing CAN-ID, MBCR, and LAFM of Receive Mailbox:

1. Set the HLTRQ bit in MCR bit to 1.

2. Determine whether the TinyCAN is during transmission or reception, or in the bus off state

and wait for recovery from transmission, reception, or bus off state.

3. The TinyCAN enters halt mode at the first bit in the intermission frame of the message and

sets the RHI bit in TCIRR0 and the HALT bit in GSR to 1. Note that the TinyCAN cannot

transmit or receive a message in halt mode.

4. Confirm that the RHI bit in TCIRR0 and the HALT bit in GSR are both set to 1 before

changing settings of the identifier, LAFM, and the MBn bit in MBCR of the Mailbox.

5. When the HLTRQ bit in MCR is cleared to 0, the TinyCAN returns to normal operation after

11 recessive bits have been continuously received.

1. Set the MBn bit in MBIMR for the corresponding Mailbox to 1 to disable interrupts. (n = 0 to

2. Determine whether the MBn bits in RXPR and RFPR are cleared to 0 to confirm that there are

no receive messages.

3. Change the settings of the identifier, LAFM, and the MBn bit in MBCR in the Mailbox.

4. Determine whether the MBn bits in RXPR and RFPR are cleared to 0 to confirm that no

message is received during reconfiguration. The function of MBIMR is not to prevent RXPR,

RFPR, or the OVRI bit in TCIRR1 from being set.

5. At this time, when the MBn bit in RXPR or RFPR is set to 1, clear the relevant bit to 0. Delete

the receive message because it cannot be determined whether the message was addressed to the

new Mailbox ID or the old Mailbox ID.

6. Then clear the MBn bit in MBIMR for the corresponding Mailbox to 0. The TinyCAN returns

to normal operation.

HD64F36034 Datasheet(PDF) 372 Page - Renesas Technology Corp