Страница 1 мировой engineering стандарты общая спецификация

30 ms
. The test device shall wait at least 
50 ms 
after the request has
been transmitted before sending any messages at high speed. This provides time for nodes on the low speed
link to switch to high speed and avoid error conditions caused by nodes transmitting at different baud rates
simultaneously. Once the 50 ms wait time is expired, the test device will be able to program a node (or nodes)
at high speed.
Note: 
All ECUs (including the tester) shall initialize their protocol converter hardware within 30 ms from the
time that the request message has been successfully transmitted on the bus. This means that any node which
uses a polling loop to service the protocol device shall ensure that the polling loop is fast enough to process
the request message and initialize the protocol converter hardware within 30 ms.
The tester can end a programming event by sending a ReturntoNormalMode ($20) request message, or by
allowing a P3
C 
timeout to occur. At the end of the programming event, each node shall transition out of high
speed mode (if high speed mode was active) and all devices shall perform a software reset. The software reset
allows a node which was just programmed to begin executing the new software/calibrations downloaded, and
is also used to synchronize communications among the nodes on the subnet.
Note: 
When programming mode is active, there shall be no response to the mode $20 request. This minimizes
possible link errors from devices switching out of high speed mode. See the description of the
ReturnToNormalMode ($20) service for tester timing requirements when exiting high speed mode.
Although devices are not required to be programmable, all nodes must be tolerant of programming mode. This
means a node shall not reject a request to initiate a programming event just because that particular node is not
programmable. A negative response shall only be sent if a node detects specific vehicle operating criteria
which must prevent the programming event from taking place. The reasons why a specific node refuses or is
unable to enter Programming mode shall be documented in the device CTS.
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