HD64F36034 datasheet(374/592 Pages) RENESAS

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Section 15 Controller Area Network for Tiny (TinyCAN)

Rev. 4.00 Mar. 15, 2006 Page 342 of 556

REJ09B0026-0400

15.5.6

TinyCAN Standby Transition

To make this LSI enter or clear standby mode when the TinyCAN is used or to make the

TinyCAN enter or clear module standby mode, follow the procedure below.

Transition from Normal Operation to Standby Mode or Module Standby Mode: This LSI can

make a transition from normal mode to standby mode with the following procedure.

1. Set the halt mode request bit (HLTRQ bit in MCR) to 1.

2. Wait until the reset/halt interrupt flag (RHI bit in TCIRR0) is set to 1.

3. Clear all interrupt request flags (in TCIRR1 and TCIRR0) to 0.

4. Make this LSI enter standby mode or module standby mode. In module standby mode, set the

MSTTC bit in TCMR to 1. Then the TinyCAN enters module standby mode.

Making the CAN bus enter the bus idle state using this procedure will reduce power consumption

of this LSI. The TinyCAN registers retain their settings in standby mode.

Transition from Standby Mode to Normal Operation: This LSI can make a transition from

standby mode to normal mode with the following procedure.

1. When data on the CAN bus changes from recessive to dominant, a falling edge is detected at

the HRXD pin.

2. This causes the WUPI bit in TCIRR1 to be set to 1, and generates an interrupt request.

3. After an interrupt request is issued, the TinyCAN registers resume operation with the settings

before entering standby mode. Change the settings at this timing if necessary.

4. To re-enable communication with the CAN bus, clear both the WUPI bit in TCIRR1 and the

HLTRQ bit in MCR to 0. After 11 recessive bits are consecutively received, communication

will resume.

Note however that the first frame to be received cannot be received normally.

Transition from Module Standby Mode to Normal Operation: The TinyCAN can make a

transition from module standby mode to normal mode with the following procedure.

1. When the MSTTC bit in TCMR is cleared to 0, the TinyCAN registers resume operation with

the settings before entering module standby mode. Change the settings at this timing if

necessary.

2. To re-enable communication with the CAN bus, clear both the HLTRQ bit in MCR to 0. After

11 recessive bits are consecutively received, communication will resume.

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