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MC9S12VR-Family - Data Sheet - Freescale Semiconductor

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15.4.3.2 Normal Mode<br />

<strong>MC9S12VR</strong> <strong>Family</strong> Reference Manual, Rev. 2.8<br />

LIN Physical Layer (S12LINPHYV1)<br />

The full functionality is available. Both receiver and transmitter are enabled. Per default (LPPUE = 1), the<br />

internal pull-up resistor is the standard LIN slave specified pull-up (30kΩ). If LPPUE = 0, this resistor is<br />

replaced by a high ohmic one (330kΩ).<br />

If an over-current condition occurs, or if RXONLY is set to 1, the module is leaving the Normal Mode to<br />

enter the Receive Only mode.<br />

If the MCU goes into stop mode, the LIN Physical Layer goes into Standby Mode.<br />

15.4.3.3 Receive Only Mode<br />

This mode has been entered because an over-current condition occurred, or because RXONLY has been<br />

set to 1.The transmitter is disabled in this mode.<br />

If this mode has been entered because of an over-current condition, RXONLY is set to 1 and can not be<br />

cleared till the condition is gone( LPOC=0).<br />

The receiver is running in full performance mode in all cases.<br />

To return to Normal mode it is mandatory to set the RXONLY bit to 0.<br />

Going into stop makes the module leave the Receive Only mode to enter the Standby Mode.<br />

15.4.3.4 Standby Mode with wake-up feature<br />

The transmitter of the physical layer is disabled. Like in the Normal and Receive Only Modes, the internal<br />

pull-up resistor can be selected to be 30kΩ or 330kΩ to maintain the LIN Bus pin in the recessive state.<br />

The receiver enters a low power mode.<br />

If LPWUE is set to 0, no wake up feature is available and the Standby Mode has the same electrical<br />

properties (current consumption, etc.) as the Shutdown Mode. This allows a low-power consumption when<br />

the wake-up feature is not needed.<br />

If LPWUE is set to 1 the receiver is able to pass wake-up events to the SCI (Serial Communication<br />

Interface). If the LIN is receiving a dominant level longer than t WUFR followed by a rising edge, it will<br />

send a pulse to the SCI which generates a wake-up interrupt.<br />

Once the MCU exits the stop mode, the LIN Physical Layer is going back to Normal or Receive Only mode<br />

depending on the status of the bits LPOC and RXONLY.<br />

NOTE<br />

Since the wake-up interrupt is requested by the SCI, no wake-up feature is<br />

available if the SCI is not used. (For example when using with a timer for<br />

bit banging)<br />

<strong>Freescale</strong> <strong>Semiconductor</strong> 437

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