Information

Table 45-71. Message buffer code for Tx buffers (continued)
CODE Description Tx Code BEFORE tx
frame
MB RTR Tx Code AFTER
successful
transmission
Comment
0b1110: TANSWER -
MB is a Tx Response
Frame from an
incoming Remote
Request Frame
TANSWER - RANSWER This is an intermediate
code that is
automatically written to
the MB by the CHI as a
result of match to a
remote request frame.
The remote response
frame will be
transmitted
unconditionally once
and then the code will
automatically return to
RANSWER (0b1010).
The CPU can also write
this code with the same
effect. The remote
response frame can be
either a data frame or
another remote request
frame depending on the
RTR bit value. See
Matching process and
Arbitration process for
details.
SRR — Substitute Remote Request
Fixed recessive bit, used only in extended format. It must be set to 1 by the user for
transmission (Tx Buffers) and will be stored with the value received on the CAN bus for
Rx receiving buffers. It can be received as either recessive or dominant. If FlexCAN
receives this bit as dominant, then it is interpreted as arbitration loss.
1 = Recessive value is compulsory for transmission in Extended Format frames
0 = Dominant is not a valid value for transmission in Extended Format frames
IDE — ID Extended Bit
This bit identifies whether the frame format is standard or extended.
1 = Frame format is extended
0 = Frame format is standard
RTR — Remote Transmission Request
This bit affects the behavior of Remote Frames and is part of the reception filter. See
Table 45-70, Table 45-71 and the description of the RRS bit in Control 2 Register
(CTRL2) for additional details.
Memory map/register definition
K20 Sub-Family Reference Manual, Rev. 1.1, Dec 2012
1144
Preliminary
Freescale Semiconductor, Inc.
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