Rainbow Electronics CAN интерфейс - Manual (Page 27)

BOSCH
ROBERT BOSCH GmbH, Postfach 50, D-7000 Stuttgart 1
Sep. 1991
Part A - page 25
ERROR because of not detecting a ’dominant’ ACK and does not detect a
’dominant’ bit while sending its PASSIVE ERROR FLAG.
Exception 2:
If the TRANSMITTER sends an ERROR FLAG because a STUFF ERROR occurred
during ARBITRATION whereby the STUFFBIT is located before the RTR bit, and
should have been ’recessive’, and has been sent as ’recessive’ but monitored as
’dominant’.
In exceptions 1 and 2 the TRANSMIT ERROR COUNT is not changed.
4. If an TRANSMITTER detects a BIT ERROR while sending an ACTIVE ERROR
FLAG or an OVERLOAD FLAG the TRANSMIT ERROR COUNT is increased by 8.
5. If an RECEIVER detects a BIT ERROR while sending an ACTIVE ERROR FLAG or
an OVERLOAD FLAG the RECEIVE ERROR COUNT is increased by 8.
6. Any node tolerates up to 7 consecutive ’dominant’ bits after sending an ACTIVE
ERROR FLAG, PASSIVE ERROR FLAG or OVERLOAD FLAG. After detecting the
14th consecutive ’dominant’ bit (in case of an ACTIVE ERROR FLAG or an
OVERLOAD FLAG) or after detecting the 8th consecutive ’dominant’ bit following a
PASSIVE ERROR FLAG, and after each sequence of additional eight consecutive
’dominant’ bits every TRANSMITTER increases its TRANSMIT ERROR COUNT by
8 and every RECEIVER increases its RECEIVE ERROR COUNT by 8.
7. After the successful transmission of a message (getting ACK and no error until END
OF FRAME is finished) the TRANSMIT ERROR COUNT is decreased by 1 unless it
was already 0.
8. After the successful reception of a message (reception without error up to the ACK
SLOT and the successful sending of the ACK bit), the RECEIVE ERROR COUNT is
decreased by 1, if it was between 1 and 127. If the RECEIVE ERROR COUNT was
0, it stays 0, and if it was greater than 127, then it will be set to a value between 119
and 127.
9. A node is ’error passive’ when the TRANSMIT ERROR COUNT equals or exceeds
128, or when the RECEIVE ERROR COUNT equals or exceeds 128. An error
condition letting a node become ’error passive’ causes the node to send an ACTIVE
ERROR FLAG.
Fault Confinement