UJA1061 データシートの表示（PDF） - NXP Semiconductors.

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UJA1061

Fault-tolerant CAN/LIN fail-safe system basis chip

NXP Semiconductors. 

NXP Semiconductors

UJA1061

Fault-tolerant CAN/LIN fail-safe system basis chip

Entering Normal mode does not activate the CAN or LIN transceiver automatically. The

CAN Mode Control (CMC) bit must be used to activate the CAN medium if required,

allowing local cyclic wake-up scenarios to be implemented without affecting the CAN-bus.

The LIN Mode Control (LMC) bit must be used to activate the LIN medium if required,

allowing local cyclic wake-up scenarios to be implemented without affecting the LIN-bus.

6.2.5 Standby mode

In Standby mode the system is set into a state with reduced current consumption.

Entering Standby mode overrides the CMC bit, allowing the CAN transceiver to enter the

low-power mode autonomously. The watchdog will, however, continue to monitor the

microcontroller (Time-out mode) since it is powered via pin V1.

In the event that the host microcontroller can provide a low-power mode with reduced

current consumption in its Standby mode or Stop mode, the watchdog can be switched off

entirely in Standby mode of the SBC. The SBC monitors the microcontroller supply current

to ensure that there is no unobserved phase with disabled watchdog and running

microcontroller. The watchdog will remain active until the supply current drops below

IthL(V1). Below this current limit the watchdog is disabled.

Should the current increase to IthH(V1), e.g. as result of a microcontroller wake-up from

application specific hardware, the watchdog will start operating again with the previously

used time-out period. If the watchdog is not triggered correctly, a system reset will occur

and the SBC will enter Start-up mode.

If Standby mode is entered from Normal mode with the selected watchdog OFF option,

the watchdog will use the maximum time-out as defined for Standby mode until the supply

current drops below the current detection threshold; the watchdog is now OFF. If the

current increases again, the watchdog is immediately activated, again using the maximum

watchdog time-out period. If the watchdog OFF option is selected during Standby mode,

the last used watchdog period will define the time for the supply current to fall below the

current detection threshold. This allows the user to align the current supervisor function to

the application needs.

Generally, the microcontroller can be activated from Standby mode via a system reset or

via an interrupt without reset. This allows implementation of differentiated start-up

behavior from Standby mode, depending on the application needs:

• If the watchdog is still running during Standby mode, the watchdog can be used for

cyclic wake-up behavior of the system. A dedicated Watchdog Time-out Interrupt

Enable (WTIE) bit enables the microcontroller to decide whether to receive an

interrupt or a hardware reset upon overflow. The interrupt option will be cleared in

hardware automatically with each watchdog overflow to ensure that a failing main

routine is detected while the interrupt service still operates. So the application

software must set the interrupt behavior each time before a standby cycle is entered.

• Any wake-up via the CAN-bus or the LIN-bus together with a local wake-up event will

force a system reset event or an interrupt to the microcontroller. So it is possible to

exit Standby mode without any system reset if required.

UJA1061_6

Product data sheet

All information provided in this document is subject to legal disclaimers.

Rev. 06 — 9 March 2010

© NXP B.V. 2010. All rights reserved.

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