TSS463 ATMEL Corporation, TSS463 Datasheet - Page 51

• Manufacturer Part Number: TSS463
• Description: VAN Data Link Controller with Serial Interface
• Manufacturer: ATMEL Corporation

Activate, Idle and
Sleep Modes
Idle and Activate
Commands
Figure 35. Idle and Activate Timings
Sleep Command
4102E–AUTO–12/04
After Reset
INT
RxD
TxD
RxD
Idle Mode
FCS
Sleep, idle and activate commands are located in the Command Register (0x03). These
three commands are general commands for the TSS463B.
After reset, the TSS463B starts in idle mode. In this mode, the oscillator operates
(CKOUT pin active) but the circuit cannot transmit or receive anything on the VAN bus.
The TxD output (pin 12) is in tri-state mode, a pull-up resistor must be provided exter-
nally or by the line driver to avoid floating state on the VAN bus. To activate the
TSS463B, the user must set the activate bit (ACTI) and reset the idle bit (IDLE).
In both cases, the idle state can be verified reading the Line Status register (0x04).
If the user sets the sleep bit (SLEEP), the TSS463B enters in sleep mode, regardless of
the values of activate and idle bits. It means that, all non-user registers are set-up to
reduce the power consumption and the internal oscillator is immediately stopped. Then,
accesses to all registers (and to the messages) via the SPI/SCI interface are impossible
and CKOUT is not provided.
To exit from this mode the user must apply either an hardware reset (external reset pin)
either an asynchronous software reset (via the SPI/SCI interface).
In a typical application (see Figure 5), using the CKOUT feature (pin 8), if the TSS463B
is put in sleep mode, the clock provided to the microcontroller is stopped. So, the system
does not run and the only way to awake this application is an external reset.
Idle Command
(max)
3 TS
Activate Mode
Activate command
8 TS
12 TS
4 TS
5 TS
Activate Mode
SOF
SOF
TS: Timeslot Period
Idle Mode
TSS463B
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