h8s-2646 Renesas Electronics Corporation., h8s-2646 Datasheet - Page 622

• Manufacturer Part Number: h8s-2646
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 15 Controller Area Network (HCAN)
15.5
1. Reset
2. HCAN sleep mode
3. Interrupts
4. Error counters
5. Register access
6. HCAN medium-speed mode
7. Register hold during standby
Rev. 5.00 Sep 22, 2005 page 596 of 1136
REJ09B0257-0500
The HCAN is reset by a reset, and in hardware standby mode and software standby mode. All
the registers are initialized in a reset, but mailboxes (message control (MCx[x])/message data
(MDx[x]) are not. However, after powering on, mailboxes (message control
(MCx[x])/message data (MDx[x]) are initialized, and their values are undefined. Therefore,
mailbox initialization must always be carried out after a reset or a transition to hardware
standby mode or software standby mode. The reset interrupt flag (IRR0) is always set after a
reset or recovery from software standby mode. This bit cannot be masked by the interrupt
mask register (IMR). When a flag is not cleared and the interrupt controller enables HCAN
interrupts, the HCAN interrupts the CPU. Clear IRR0 during initialization.
The bus operation interrupt flag (IRR12) in the interrupt register (IRR) is set by bus operation
in HCAN sleep mode. Therefore, this flag is not used by the HCAN to indicate sleep mode
release. Also note that the reset status bit (GSR3) in the general status register (GSR) is set in
sleep mode.
When the mailbox interrupt mask register (MBIMR) is set, the interrupt register (IRR8,2,1) is
not set by reception completion, transmission completion, or transmission cancellation for the
set mailboxes.
In the case of error active and error passive, REC and TEC normally count up and down. In the
bus off state, 11-bit recessive sequences are counted (REC + 1) using REC. If REC reaches 96
during the count, IRR4 and GSR1 are set.
Byte or word access can be used on all HCAN registers. Longword access cannot be used.
In medium-speed mode, the HCAN register cannot be read from or written to.
All registers in the HCAN are initialized on entering hardware standby or software modes.
Usage Notes