![Motorola ColdFire MCF5281 User Manual Download Page 533](http://html.mh-extra.com/html/motorola/coldfire-mcf5281/coldfire-mcf5281_user-manual_245144533.webp)
MOTOROLA
Chapter 25. FlexCAN
25-7
Message Buffers
25.3.1.2 Fields for Extended Format Frames
Table 25-5 describes the message buffer fields used only for extended identifier format
frames.
25.3.1.3 Fields for Standard Format Frames
Table 25-6 describes the message buffer fields used only for standard identifier format
frames.
25.3.2 Message Buffer Memory Map
The message buffer memory map starts at an offset of 0x80 from the FlexCAN’s base
address (0x1C_0000). The 256-byte message buffer space is fully used by the 16 message
buffer structures.
Table 25-5. Extended Format Frames
Field
Description
ID[28:18]/[17:15] Contains the 14 most significant bits of the extended identifier, located in the ID HIGH word of the
message buffer.
Substitute
Remote Request
(SRR)
Contains a fixed recessive bit, used only in extended format. Should be set to one by the user for
Tx buffers. It will be stored as received on the CAN bus for Rx buffers. This is a bit in the ID HIGH
word of the message buffer.
ID Extended (IDE) If extended format frame is used, this field should be set to one. If zero, standard format frame
should be used. This is a bit in the ID HIGH word of the message buffer.
ID[14:0]
Bits [14:0] of the extended identifier, located in the ID LOW word of the message buffer.
Remote
Transmission
Request (RTR)
This bit is located in the least significant bit of the ID LOW word of the message buffer;
0 Data Frame
1 Remote Frame.
Table 25-6. Standard Format Frames
Field
Description
ID[28:18]
Contains bits [28:18] of the identifier, located in the ID HIGH word of the message buffer. The four
least significant bits in this register (corresponding to the IDE bit and ID[17:15] for an extended
identifier message) must all be written as logic zeros to ensure proper operation of the FlexCAN.
RTR
Remote Transmission Request. This bit is located in the ID HIGH word of the message buffer.
0 data frame
1 remote frame.
If the FlexCAN transmits this bit as a one and receives it as a zero, an “arbitration loss” is
indicated. If the FlexCAN transmits this bit as a zero and receives it as a one, a bit error is
indicated.
If the FlexCAN transmits a value and receives a matching response, a successful bit transmission
is indicated.
16-Bit Time Stamp The 16-bit time stamp, located in the ID LOW word of the message buffer, is not needed for
standard format, and is used in a standard format buffer to store the 16-bit value of the
free-running timer. The timer value is captured at the beginning of the identifier field of the frame
on the CAN bus.
Summary of Contents for ColdFire MCF5281
Page 124: ...3 20 MCF5282 User s Manual MOTOROLA EMAC Instruction Set Summary ...
Page 141: ...MOTOROLA Chapter 5 Static RAM SRAM 5 5 SRAM Programming Model ...
Page 142: ...5 6 MCF5282 User s Manual MOTOROLA SRAM Programming Model ...
Page 168: ...6 26 MCF5282 User s Manual MOTOROLA Interrupts ...
Page 186: ...7 18 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 228: ...9 22 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 246: ...10 18 MCF5282 User s Manual MOTOROLA Low Power Wakeup Operation ...
Page 254: ...11 8 MCF5282 User s Manual MOTOROLA Memory Map and Registers ...
Page 264: ...12 10 MCF5282 User s Manual MOTOROLA Chip Select Registers ...
Page 280: ...13 16 MCF5282 User s Manual MOTOROLA Misaligned Operands ...
Page 314: ...14 34 MCF5282 User s Manual MOTOROLA MCF5282 External Signals ...
Page 339: ...MOTOROLA Chapter 15 Synchronous DRAM Controller Module 15 25 SDRAM Example ...
Page 340: ...15 26 MCF5282 User s Manual MOTOROLA SDRAM Example ...
Page 356: ...16 16 MCF5282 User s Manual MOTOROLA DMA Controller Module Functional Description ...
Page 408: ...17 52 MCF5282 User s Manual MOTOROLA Buffer Descriptors ...
Page 446: ...20 24 MCF5282 User s Manual MOTOROLA Interrupts ...
Page 474: ...22 18 MCF5282 User s Manual MOTOROLA Programming Model ...
Page 510: ...23 36 MCF5282 User s Manual MOTOROLA Operation ...
Page 526: ...24 16 MCF5282 User s Manual MOTOROLA I2C Programming Examples ...
Page 672: ...28 12 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 718: ...29 46 MCF5282 User s Manual MOTOROLA Motorola Recommended BDM Pinout ...
Page 750: ...32 8 MCF5282 User s Manual MOTOROLA Ordering Information ...