TSS461 ATMEL Corporation, TSS461 Datasheet - Page 21

• Manufacturer Part Number: TSS461
• Description: VAN Data Link Controller
• Manufacturer: ATMEL Corporation

Generation of
Internal Signals
RI Signal (Return to
Idle)
SDC Signal
(Synchronous
Diagnosis Clock)
TIP Signal
(Transmission In
Progress)
4194C–AUTO–01/06
•
This signal is used to return to nominal mode in the three specified selection modes (see
section “Diagnosis States” and section “Programming Modes”). The RI signal is disabled in auto-
matic selection mode.
The RI signal is a pulse generated when an EOF is detected. So, at the end of each frame, the
user, regarding the diagnosis status bit Sa, Sb & Sc, can select its own choice.
T h i s t i m e b a s e i s u s e d b y d i a g n o s i s s y s t e m i n a u t o m a t i c s e l e c t i o n m o d e ( s e e
section “Programming Modes”) when no event is recorded on the bus.
The SDC is generated either by a special SDC divider connected to the timeslot clock, or manu-
ally. The SDC clock period must be longer compared to the timeslot duration.
A typical SDC period should be greater than the maximum frame length appearing on the VAN
network.
This signal must be enabled to allow the transmission diagnosis (see section “Transition
Analyses”).
The TIP turns on synchronously at the beginning of the transmission:
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The TIP turns off synchronously at the end of the transmission:
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This signal is not generated when the transmission logic only sends an ACK.
filters) with the data transmitted on TxD output.
At a time when the transmission logic generates a dominant (recessive transition), the inputs
can give different values. Taking into account the filtering delay, the bus line seen as
dominant is assumed to be correct, the other one, recessive, is considered faulty. The
diagnosis mode is changed to reflect that.
Protocol fault:
The protocol fault is detected by counting the number of consecutive dominant timeslots.
If eight consecutive timeslots are dominant, the diagnosis mode will change to the major
error mode.
For asynchronous bus access, the beginning of SOF,
For synchronous bus access, the beginning of the identifier field,
For a request of in frame reply, the RTR bit of the command field.
after EOF
after a losing of arbitration or a code violation detection
for a requester of in frame reply, when the arbitration is lost on RTR the bit.
TSS461E
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