33663 datasheet(28/37 Pages) FREESCALE

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Analog Integrated Circuit Device Data



Freescale Semiconductor

33663

FUNCTIONAL DEVICE OPERATION

OPERATIONAL MODES

FUNCTIONAL DEVICE OPERATION

OPERATIONAL MODES

As described by the following, the 33663L, 33663J, and 33663S have two operational modes, Normal and Sleep. In addition,

there are two transitional modes: Awake mode which allows the device to go into Normal mode, and Preparation to Sleep mode

which allows the device to go into Sleep mode.

NORMAL OR SLOW BAUD RATE

In the Normal mode, the LIN bus can transmit and receive information.

The 33663L and 33663S (20 kbps) have a slew rate and timing compatible with Normal Baud Rate and LIN protocol

specification 1.3, 2.0, 2.1, and 2.2.

The 33663J (10 kbps) has a slew rate and timing compatible with Low Baud Rate.

From Normal mode, the three devices can enter into Fast Baud Rate (Toggle function).

FAST BAUD RATE

In fast baud rate, the slew rate is around 10 times faster than the normal baud rate. This allows very fast data transmission

(>100 kbps) -- for example, electronic control unit (ECU) tests and microcontroller program download. The bus pull-up resistor

might be adjusted to ensure a correct RC time constant in line with the high baud rate used.

The following sequence is applicable to both LIN Modules independently.

Fast baud rate is entered via a special sequence (called toggle function) as follows:

1. EN1 pin set LOW while TXD1 is HIGH

2. TXD1 stays HIGH for 12.5 µs min

3. TXD1 set LOW for 12.5 µs min

4. TXD1 pulled HIGH for 12.5 µs min

5. EN1 pin set LOW to HIGH while TXD1 still HIGH

The LIN Module enters into the fast baud rate if the delay between step 1 to step 5 is 45 µs maximum. The toggle function is

described in Figures 19. Once in fast baud rate, the same toggle function just described previously is used to bring the LIN Module

1 back into normal baud rate.

Fast baud rate selection is reported to the MCU by the RXD1 pin. Once the LIN Module 1 enters in this fast baud rate, the

RXD1 pin goes at low level for t5. When LIN Module 1 returns to normal baud rate with the same toggle function, the RXD1 pin

stays high. Both sequences are illustrated in Figures 19 and 20.

PREPARATION TO SLEEP MODE

The following sequence is applicable to both LIN Modules simultaneously or separately. Here it is detailed with the LIN Module

To enter the Preparation to Sleep mode, EN1 must be low for a delay higher than tLWUE.

• If the WAKE1 pin state doesn’t change during tSD and tLWUE, then the LIN Module 1 goes in Sleep Mode.

• If the WAKE1 pin state changes during tSD and if tWF is reached after end of tSD, then the LIN Module 1 goes into Sleep

mode after the end of tSD timing.

• If the WAKE1 pin state changes during tSD and tWF delay has been reached before end of tSD, then the LIN Module 1 goes

into Awake Mode.

• If the WAKE1 pin state changes before tSD and the delay tWF ends during tSD, then the LIN Module 1 goes in Awake Mode.

• If EN1 goes high for a delay higher than tLWUE, the LIN Module 1 returns in Normal mode.

SLEEP MODE

The following Sleep mode paragraph is applicable to both LIN Modules simultaneously or separately. LIN Module 1 is an

example.

To enter into Sleep mode, EN1 must be low for a delay longer than tSD and the WAKE1 pin must stay in the same state (High

or Low) during this delay. The LIN Module 1 conditions to not enter Sleep mode, but enter Awake mode are detailed in the

Preparation into Sleep Mode chapter. See Figure 23.

33663 Datasheet(PDF) 28 Page - Freescale Semiconductor, Inc

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