MLX80004 Datasheet, PDF (18/38 Pages) Melexis Microelectronic Systems – Enhanced Universal Dual/Quad LIN Transceiver

MLX80002/MLX80004
Enhanced Universal Dual/Quad LIN Transceiver
Datasheet
8.5. Wake Up
When in sleep mode the MLX80004/2 offers three wake-up procedures:
 In applications with continuously powered ECU a wake up via mode transition to active modes is possible by
setting the MODEx pins to high level. (see chapter 4.3 Active Modes)
 Remote wake-up via LINx bus request
After a falling edge on the LINx bus followed by a dominant voltage level for longer than the specified
value(t_{wu_remote}) and a rising edge on pin LINx will cause a remote wake up (see Figure 6 at page 19)
 Local wake-up via a negative edge on pin WAKE
A negative edge on the pin WAKE and a dominant voltage level for longer than the specified time (t_{wu_local}) will
cause a local wake-up. The current for an external switch has to be provided by an external pull up resistor
R_WK. For a reverse current limitation in case of a closed external switch and a negative ground shift or an ECU
loss of ground a protection resistor R_{WK_prot} between pin WAKE and the switch is recommended. (see Figure 7
at page 20)
The pin WAKE provides a weak pull up current towards the battery voltage that provides a HIGH level on the
pin in case of open circuit failures or if no local wake up feature is required. In such applications it is
recommended to connect the pin WAKE to pin Vs via a resistor of 10k ohms.
8.6. Wake Up Source Recognition
The device can distinguish between a local wake-up event (pin WAKE) and a remote wake-up event in dependence of
the requesting LINx bus.
Local Wake Up
In case of a local wakeup via WAKE pin, the wake up request is indicated by an active LOW on pin RxD1. The wake-up
source flag is set and is indicated by an active LOW on pin TxD1.
The wake-up source flag can be read if an external pull up resistor at TxD1 towards the microcontroller supply voltage
has been added and the MLX80004/2 is still in standby mode:
When the microcontroller confirms an active mode operation by setting the pin MODE0/1 to HIGH, both the wake-up
request on pin RxD1 as well as the wake-up source flag on pin TxD1 are reset immediately.
Remote Wake Up
In case of a remote wake-up via a LINx bus, the source of the wake-up request will be indicated by the RxDx pin that
belongs to the LINx pin. (example: LOW level on RxD4 and floating RxD1-3 indicate a wake-up request on LIN4).
The wake up source flag at TxD1 remains floating.
This allows following the wake-up request of the requesting LIN bus while remaining the other LIN bus channels in
recessive mode (no wake up occurs in these LIN networks).
After a mode transition into any active mode by setting the pin MODE0/1 to HIGH, the active LOW wake-up request on
pin RxDx is reset immediately.
If the device is not set into an active mode after a wake up request (either local or remote) then it will return into sleep
mode after t_dsleep.
Revision 021 – Sept 2016
Page 18 of 38