Rainbow Electronics ATA6670 - Manual (Page 6)

6
9204C–AUTO–09/11
Atmel ATA6670 [Preliminary]
3.11 Operation Modes
1. Normal mode
This is the normal transmitting and receiving mode. All features are available.
2. Sleep mode
In this mode the transmission path is disabled and the device is in low power mode.
Supply current from V
Batt
is typically 10µA. A wake-up signal (either from the LIN bus
or the WAKE2 input) is detected and switches the corresponding transceiver to
fail-safe mode. If EN then switches to high, normal mode is activated. Input debounce
timers at pin WAKE2 (t
WAKE
), LIN (t
BUS
) and EN (t
sleep,tnom
) prevent undesirable
wake-up events due to automotive transients or EMI. The internal termination bet-
ween pin LIN and pin VS is disabled. Only a weak pull-up current (typical 10µA)
between pin LIN and pin VS is present. Sleep mode can be activated independently
of the current level on pin LIN.
3. Fail-safe mode
At system power-up or after a wake-up event, the transceiver automatically switches
to fail-safe mode. When VS2 exceeds 5V, the transceiver 2 switches the INH2 pin to
the VS2 level. LIN communication is switched off. The microcontroller of the applica-
tion then confirms normal mode by setting the EN pin to high.
Figure 3-1. Operating Modes
Table 3-1. Table of Modes
Operating Mode Transceiver RXD LIN
Fail-safe Off
High, except after
wake-up
Recessive
Normal On LIN-depending TXD-depending
Sleep Off High-ohmic Recessive
a: Power- u p (V
S
> 3 V)
b: V
S
< 5V
c: B us w a ke- u p event
(only Tr a n s ceiver 2)
d: W a ke- u p from w a ke s witch
EN = 1
a nd not b
c or d
b b
a
EN = 0
EN = 1
Fail- S afe Mode
Power-up
Comm u nic a tion: OFF
RXD: s ee t ab le of Mode s
Tr a n s ceiver 2: INH2 s witch ON if V S 2 > 5V
S leep Mode
Comm u nic a tion: OFF
Tr a n s ceiver 2: INH2 s witch OFF
Normal Mode
Comm u nic a tion: ON
Tr a n s ceiver 2: INH2 s witch ON
Loc a l w a ke- u p event
Go to s leep comm a nd