Foreign Remote Requests - Infineon Technologies TC1728 User Manual

20.3.11.8 Foreign Remote Requests

When a Remote Frame has been received on a CAN node and is stored in a message
object, a transmit request is set to trigger the answer (transmission of a Data Frame) to
the request or to automatically issue a secondary request. If the Foreign Remote
Request Enable bit MOFCRn.FRREN is cleared in the message object in which the
remote request is stored, MOSTATn.TXRQ is set in the same message object.
If bit FRREN is set (FRREN = 1: foreign remote request enabled), TXRQ is set in the
message object that is referenced by pointer MOFGPRn.CUR. The value of CUR is,
however, not changed by this feature.
Although the foreign remote request feature works independently of the selected
message mode, it is especially useful for gateways to issue a remote request on the
source bus of a gateway after the reception of a remote request on the gateway
destination bus. According to the setting of FRREN in the gateway destination object,
there are two capabilities to handle remote requests that appear on the destination side
(assuming that the source object is a receive object and the destination is a transmit
object, i.e. DIR
source
FRREN = 0 in the Gateway Destination Object
1. A Remote Frame is received by gateway destination object.
2. TXRQ is set automatically in the gateway destination object.
3. A Data Frame with the current data stored in the destination object is transmitted on
the destination bus.
FRREN = 1 in the Gateway Destination Object
1. A Remote Frame is received by gateway destination object.
2. TXRQ is set automatically in the gateway source object (must be referenced by CUR
pointer of the destination object).
3. A remote request is transmitted by the source object (which is a receive object) on
the source CAN bus.
4. The receiver of the remote request responds with a Data Frame on the source bus.
5. The Data Frame is stored in the source object.
6. The Data Frame is copied to the destination object (gateway action).
7. TXRQ is set in the destination object (assuming GDFS
8. The new data stored in the destination object is transmitted on the destination bus,
in response to the initial remote request on the destination bus.
User's Manual
MultiCAN, V2.24
Controller Area Network Controller (MultiCAN)
= 0 and DIR
destination
= 1):
source
20-55
TC1728
= 1).
V1.0, 2011-12