DSPIC33FJ64GP802-I Datasheet, PDF (228/436 Pages) Microchip Technology – 16-bit Digital Signal Controllers (up to 128 KB Flash and 16K SRAM) with Advanced Analog

dsPIC33FJ32GP302/304, dsPIC33FJ64GPX02/X04, AND dsPIC33FJ128GPX02/X04
19.2 Frame Types
The ECAN module transmits various types of frames
which include data messages, or remote transmission
requests initiated by the user, as other frames that are
automatically generated for control purposes. The
following frame types are supported:
• Standard Data Frame:
A standard data frame is generated by a node
when the node wishes to transmit data. It includes
an 11-bit Standard Identifier (SID), but not an 18-
bit Extended Identifier (EID).
• Extended Data Frame:
An extended data frame is similar to a standard
data frame, but includes an extended identifier as
well.
• Remote Frame:
It is possible for a destination node to request the
data from the source. For this purpose, the
destination node sends a remote frame with an
identifier that matches the identifier of the
required data frame. The appropriate data source
node sends a data frame as a response to this
remote request.
• Error Frame:
An error frame is generated by any node that
detects a bus error. An error frame consists of two
fields: an error flag field and an error delimiter
field.
• Overload Frame:
An overload frame can be generated by a node as
a result of two conditions. First, the node detects a
dominant bit during interframe space which is an
illegal condition. Second, due to internal condi-
tions, the node is not yet able to start reception of
the next message. A node can generate a maxi-
mum of 2 sequential overload frames to delay the
start of the next message.
• Interframe Space:
Interframe space separates a proceeding frame
(of whatever type) from a following data or remote
frame.
DS70292G-page 228
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