NXP Semiconductors LPC24XX UM10237 - Manual (Page 518)

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User manual Rev. 04 — 26 August 2009 518 of 792
NXP Semiconductors
UM10237
Chapter 18: LPC24XX CAN controllers CAN1/2
18. Examples of acceptance filter tables and ID index values
18.1 Example 1: only one section is used
SFF_sa < ENDofTable OR
SFF_GRP_sa < ENDofTable OR
EFF_sa < ENDofTable OR
EFF_GRP_sa < ENDofTable
The start address of a section is lower than the end address of all programmed CAN
identifiers.
18.2 Example 2: all sections are used
SFF_sa < SFF_GRP_sa AND
SFF_GRP_sa < EFF_sa AND
EFF_sa < EFF_GRP_sa AND
EFF_GRP_sa < ENDofTable
In cases of a section not being used, the start address has to be set onto the value of the
next section start address.
18.3 Example 3: more than one but not all sections are used
If the SFF group is not used, the start address of the SFF Group Section (SFF_GRP_sa
register) has to be set to the same value of the next section start address, in this case the
start address of the Explicit SFF Section (SFF_sa register).
Fig 90. Clearing message lost
message
handler
access
ARM
processor
access
01 11 01 11 11 00
1st Object
write
2nd Object
write
1st Object
read
3rd Object
write
write
SEM
write
D2
write
D1
write
ID,
SEM
write
SEM
write
D2
write
D1
write
ID,
SEM
write
SEM
write
D2
write
D1
write
ID,
SEM
read
SEM
read
D2
read
D1
read
SEM clear
SEM
IntPndx
semaphore
bits
look-up
table
access
MsgLostx