CP3BT23_14 Datasheet, PDF (130/324 Pages) Texas Instruments – CP3BT23 Reprogrammable Connectivity Processor with Bluetooth and Dual CAN Interfaces

CP3BT23
SNOSCX3A – JULY 2013 – REVISED JANUARY 2014
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Interframe Space
Data and remote frames are separated from every preceding frame (data, remote, error and overload
frames) by the interframe space (see Figure 18-9). Error and overload frames are not preceded by an
interframe space; they can be transmitted as soon as the condition occurs. The interframe space consists
of a minimum of three bit fields depending on the error state of the node.
3
INT
ANY FRAME
INTERFRAME SPACE
8
SUSPEND
TRANSMIT
Bus Idle
DATA FRAME OR
REMOTE FRAME
rrrrrrrrrrrr rrrrrrr
INT = Intermission
Suspend Transmission is only for error passive nodes.
rrrd
Figure 18-9. Interframe Space
Note:
d = dominant
r = recessive
DS026
18.2.4 Error Types
Bit Error
A CAN device which is currently transmitting also monitors the bus. If the monitored bit value is different
from the transmitted bit value, a bit error is detected. However, the reception of a “dominant” bit instead of
a “recessive” bit during the transmission of a passive error flag, during the stuffed bit stream of the
arbitration field, or during the acknowledge slot is not interpreted as a bit error.
Stuff Error
A stuff error is detected if 6 consecutive bits occur without a state change in a message field encoded with
bit stuffing.
Form Error
A form error is detected, if a fixed frame bit (e.g., CRC delimiter, ACK delimiter) does not have the
specified value. For a receiver, a “dominant” bit during the last bit of End of Frame does not constitute a
frame error.
Bit CRC Error
A CRC error is detected if the remainder from the CRC calculation of a received CRC polynomial is non-
zero.
Acknowledgment Error
An acknowledgment error is detected whenever a transmitting node does not get an acknowledgment
from any other node (i.e., when the transmitter does not receive a “dominant” bit during the ACK frame).
130 CAN Module
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