
XC161 Derivatives
Peripheral Units (Vol. 2 of 2)
TwinCAN Module
User’s Manual
21-37
V2.2, 2004-01
TwinCAN_X1, V2.1
Bit SRREN determines, whether a remote frame, received on the destination side, is
transferred through the gateway to the source node or is directly answered by a data
frame generated on the destination side.
The functionality of the shared gateway mode is optimized to support different scenarios:
•
a data source, connected with CAN node A, transmits continuously data frames,
which have to be automatically emitted on the destination CAN bus by CAN node B.
The corresponding transfer state transitions are 1 - 2 - …
•
a data source, connected with CAN node A, transmits continuously data frames,
which have to be emitted by CAN node B upon a matching remote frame received
from the destination CAN bus.
The corresponding transfer state transitions are 7 - 4 - 2 - …
•
a data source, connected with CAN node A, transmits a data frame upon a matching
remote frame, which has been triggered by a matching remote frame received by
CAN node B. The respective data frame has to be emitted again on the destination
CAN bus by CAN node B.
The corresponding transfer state transitions are 5 - 6 - 1 - 3 - …
Depending on the application, the shared gateway message object can be initialized as
receive object on the source side or transmit object on the destination side via an
appropriate configuration of NODE, DIR, GDFS and SRREN. The various transfer states
are illustrated in
Figure 21-22 Transfer States in Shared Gateway Mode
MCA05492
Transmit Object
Destination Side
TXRQ Reset
Receive Object
Source Side
TXRQ Set
5
Remote Frame
Reception,
SRREN = ‘1’
Transmit Object
Destination Side
TXRQ Set
Receive Object
Source Side
TXRQ Reset
2
Data Frame
Transmission,
SRREN = ‘0’
1
Data Frame
Reception,
GDFS = ‘1’
4
Remote Frame Reception,
SRREN = ‘0’
Data Frame Transmission, SRREN = ‘1’
Remote Frame Transmission
6
Data Frame
Reception,
GDFS = ‘0’
7
3