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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
311 of 571
NXP Semiconductors
UM10316
Chapter 21: LPC29xx CAN 0/1
By means of the message-disable bits particular CAN identifiers can be turned on and off
dynamically from acceptance filtering. When the acceptance filter function is enabled only
the message-disable bits in the acceptance-filter look-up table memory can be changed
by software. Disabled entries must maintain the ascending sequence of identifiers.
8.3 Standard frame-format group identifier section
The table of the standard frame- format group identifier section contains paired upper and
lower bounds, one pair per word. These pairs must be arranged in ascending numerical
order (see
This section starts with the CASFGSA start address register and contains the identifiers
index (h + i) lower bound to index (h + i + j
−
1) upper bound. The bit allocation of the first
word is given in
.
By means of the message-disable bits particular CAN identifier groups can be turned on
and off dynamically from acceptance filtering. When the acceptance-filter function is
enabled only the message-disable bits in the acceptance-filter look-up table memory can
be changed by software. Note that in this section the lower bound and upper bound
message-disable bit must always have the same value. Disabled entries must maintain
the ascending sequence of identifiers.
8.4 Extended frame-format explicit identifier section
If extended identifiers (29-bit) are used they can be configured either in this section or in
the following section. The table of extended frame-format explicit identifiers must be
arranged in ascending numerical order (see
).
This section starts with CAEFESA start-address register and contains the identifiers index
(h + i + j) to index (h + i + j + k
−
1). The bit allocation of the first word is given in
12
MDB
Odd index: message disable bit. Logic 0 is message enabled and
logic 1 is message disabled
11
-
Not used
10 to 0
ID[28:18]
Odd index: 11-bit CAN 2.0 B identifier
Table 262. Standard frame-format explicit identifier section
…continued
Bit
Symbol
Description
Table 263. SFF group identifier section
Bit
Symbol
Description
31 to 29 SCC
Lower bound: CAN controller number
28
MDB
Lower bound: message disable bit. Logic 0 is message enabled and
logic 1 is message disabled
27
-
Not used
26 to 16 ID[28:18]
Lower bound: 11-bit CAN 2.0 B identifier
15 to 13 SCC
Upper bound: CAN controller number
12
MDB
Upper bound: message-disable bit. Logic 0 is message enabled and
logic 1 is message disabled
11
-
Not used
10 to 0
ID[28:18]
Upper bound: 11-bit CAN 2.0 B identifier