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(4)
ELISA specific events
(a) Timer event processing by ELISA
There are four timer events available (periodic intervals). Each of the timer events can be enabled
or disabled individually. Whenever a timer event occurs, the event is reported to ELISA. ELISA will
start the event processing similar to events given by messages, but the event pointers are read from
pointer buffers located in ELISA.
(b) Script Events
For better flexibility a script event is available. The script event can be used if an event script
requires more than 8 commands. Basically ELISA limits the total number of commands executed for
one event to 8. If more commands are required the primary script can generate an additional event,
so-called script event. When generating a script event the pointer on the first command must be
defined at the same time.
The application software can also generate a script event.
(c) Data Consistency
As ELISA accesses the message buffers as well as the CPU and the CAN interfaces, some mecha-
nisms were implemented to ensure that data inconsistency is detected.
To reduce the risk of data inconsistency the application software should not operate any message
with the ERQ flag set without ensuring that ELISA is not handling that message. The CPU can
ensure that by checking which event is under processing and clearing the ERQ flag if the message
is not under processing.
ELISA stops its operation and generates and interrupt under the following conditions:
• any of the M_STATm register flags of the source message m handled by ELISA is written (DN,
ERQ, TRQ, RDY) (m = 00 to 63)
• ELISA tries to write to a message with RDY flag cleared (0) or TRQ flag set (1)
• ELISA tries to read from a message with RDY flag cleared (0)
The EHDL bit defines how ELISA terminates its operation (writing back source message or not).
The application software must restart ELISA by writing to a special register.
(d) Debugging
For debugging the operation of ELISA the BREAK command can be used (refer to chapter 13.5.3).
Chapter 13 FCAN Interface Function
Preliminary User's Manual U14913EE1V0UM00
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