Usage Notes; Module Stop Mode Setting; Reset; Hcan Sleep Mode - Renesas H8SX/1500 Series Hardware Manual

32-bit cisc microcomputer

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Section 13 Controller Area Network (HCAN)

Usage Notes

HCAN operation can be disabled or enabled using the module stop control register. The HCAN

operation is set to be halted initially. Register access is enabled by clearing module stop mode. For

details, refer to section 19, Power-Down Modes.

The HCAN is reset by a power-on reset and a transition to software standby mode. All the

registers are initialized by a reset, however mailboxes (message control (MCx[x])/message data

(MDx[x])) are not initialized. Mailboxes (message control (MCx[x])/message data (MDx[x])) are

initialized after power-on and at this time, their initial values are undefined. Therefore, always

initialize mailboxes after a power-on reset, a transition to software standby mode, or a transition to

module stop mode. After a power-on reset, recovery from software standby mode, or clearing

module stop mode, the reset interrupt flag (IRR0) is automatically set. Since this bit cannot be

masked in the interrupt mask register (IMR), an HCAN interrupt will be initiated immediately

after an HCAN interrupt is enabled by the interrupt controller without clearing the flag. IRR0

should therefore be cleared at initialization.

The bus operation interrupt flag (IRR12) in the interrupt register (IRR) is set by CAN bus

operation in HCAN sleep mode. Therefore, this flag is not used by the HCAN to indicate sleep

mode release. Note that the reset status bit (GSR3) in the general status register (GSR) is set even

in sleep mode.

Rev. 3.00 Mar. 14, 2006 Page 504 of 804

REJ09B0104-0300

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