mc33662 Freescale Semiconductor, Inc, mc33662 Datasheet - Page 25

• Manufacturer Part Number: mc33662
• Description: Lin 2.1 / Saej2602-2, Lin Physical Layer
• Manufacturer: Freescale Semiconductor, Inc

Table
operational modes, Normal and Sleep. In addition, there are
two transitional modes: Awake mode and Preparation to
Sleep mode. The Awake mode allows the device to go into
Normal mode. The Preparation to Sleep mode allows the
device to go into Sleep mode.
NORMAL OR SLOW BAUD RATE
information.
timing compatible with Normal Baud Rate and LIN protocol
specification 1.3, 2.0, and 2.1.
compatible with Low Baud Rate.
Baud Rate (Toggle function).
FAST BAUD RATE
than the Normal Baud Rate. This allows very fast data
transmission (> 100 kbps) -- for instance, for 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.
toggle function) as follows:
between Step 1 to Step 5 is 45 µs maximum. The toggle
function is described in
the same toggle function just described previously is used to
bring the device back into Normal Baud Rate.
pin. Once the device enters in this Fast Baud Rate, the RXD
pin goes at low level for t
Baud Rate with the same toggle function, the RXD pin stays
high. Both sequences are illustrated in
PREPARATION TO SLEEP MODE
for a delay higher than t
then the 33662 goes into Sleep mode.
Analog Integrated Circuit Device Data
Freescale Semiconductor
As described below and depicted in
In the Normal mode, the LIN bus can transmit and receive
The 33662L and 33662S (20 kbps) have a slew rate and
The 33662J (10 kbps) has a slew rate and timing
From Normal mode, the three devices can enter into Fast
In Fast Baud Rate, the slew rate is around 10 times faster
Fast Baud Rate is entered via a special sequence (called
1- EN pin set LOW while TXD is HIGH
2- TXD stays HIGH for 12.5 µs min
3- TXD set LOW for 12.5 µs min
4- TXD pulled HIGH for 12.5 µs min
5- EN pin set LOW to HIGH while TXD still HIGH
The device enters into the Fast Baud Rate if the delay
Fast Baud Rate selection is reported to the MCU by RXD
To enter the Preparation to Sleep mode, EN must be low
If the WAKE pin state doesn’t change during t
7, the 33662L, 33662J, and 33662S have two
Figures
5
LWUE
. When the device returns in Normal
.
22. Once in Fast Baud Rate,
FUNCTIONAL DEVICE OPERATION
Figure 29
Figures 22
SD
and
OPERATIONAL MODES
and t
and 23.
LWUE
reached after end of t
mode after the end of t
has been reached before the end of t
into Awake mode.
t
returns to Normal mode.
SLEEP MODE
longer than t
(High or Low) during this delay.
in Awake mode are detailed in the Preparation into Sleep
mode chapter. See
device is in Low Power mode. Supply current from V
very low (6.0 µA typical value). Wake-up can occur from LIN
bus activity, from the EN pin and from the WAKE input pin. If
during the preparation to Sleep mode delay (t
goes low due to LIN network communication, the device still
enters into the Sleep mode. The device can be awakened by
a recessive to dominant start, followed by a dominant to
recessive state after t > t
mode.
is connected and the 30 kOhm is disconnected.
DEVICE POWER-UP (Awake Transitional Mode)
the Power On Reset voltage, the device automatically
switches after a 160 µs delay time to the Awake transitional
mode. It switches the INH pin to a HIGH state and RXD to a
LOW state. See
DEVICE WAKE-UP EVENTS
Sleep mode by three wake-up events:
• Remote wake-up via LIN bus activity
• Via the EN pin
• Toggling the WAKE pin
Remote Wake from LIN Bus (Awake Transitional Mode)
than t
transition, wait for t > t
WF
If the WAKE pin state changes during t
If the WAKE pin state changes during t
If the WAKE pin state changes before t
If EN goes high for a delay higher than t
To enter into Sleep mode, EN must be low for a delay
The device conditions to not enter in Sleep mode but enter
In Sleep mode, the transmission path is disabled and the
After a Wake-up event, the device enters into Awake
In the Sleep mode, the internal 725 kOhm pull-up resistor
At power-up (V
The 33662L, 33662J, and 33662S can be awakened from
The device is awakened by a LIN dominant pulse longer
ends during t
WUF
. Dominant pulse means: a recessive to dominant
SD
and the Wake pin must stay in the same state
Figure
SD
SUP
Figure
then the device goes into Awake mode.
SD
rises from zero), when V
WUF
SD
24.
then the device goes into Sleep
WUF
timing.
, then a dominant to recessive
26.
FUNCTIONAL DEVICE OPERATION
.
SD
OPERATIONAL MODES
then the device goes
SD
SD
SD
LWUE
SD
and if t
and t
and the delay
SUP
), the LIN bus
, the 33662
WF
is above
WF
SUP
delay
is
33662
is
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