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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
345 of 571
NXP Semiconductors
UM10316
Chapter 21: LPC29xx CAN 0/1
11. FullCAN mode
The FullCAN mode is based on capabilities provided by the CAN Gateway module used in
the LPC2000 family of products. This block uses the Acceptance Filter to provide filtering
for both CAN channels.
The concept of the CAN Gateway block is mainly based on a BasicCAN functionality. This
concept fits perfectly in systems where a gateway is used to transfer messages or
message data between different CAN channels. A BasicCAN device is generating a
receive interrupt whenever a CAN message is accepted and received. Software has to
move the received message out of the receive buffer from the according CAN controller
into the user RAM.
To cover dashboard like applications where the controller typically receives data from
several CAN channels for further processing, the CAN Gateway block was extended by a
so-called FullCAN receive function. This additional feature uses an internal message
handler to move received FullCAN messages from the receive buffer of the according
CAN controller into the FullCAN message object data space of Look-up Table RAM.
When fullCAN mode is enabled, the Acceptance Filter itself takes care of receiving and
storing messages for selected Standard ID values on selected CAN buses, in the style of
“FullCAN” controllers.
In order to set this bit and use this mode, two other conditions must be met with respect to
the contents of Acceptance Filter RAM and the pointers into it:
Table 297. CAN controller central miscellaneous-status register bit description
* = reset value
Bit
Symbol
Access
Value
Description
31 to 10 reserved
R
-
Reserved; do not modify. Read as logic 0
9
BS1
R
CAN controller 1 bus status
1
The CAN controller is currently prohibited from
bus activity because the transmit error counter
has reached its limiting value of FFh
0*
8
BS0
R
CAN controller 0 bus status
1
The CAN controller is currently prohibited from
bus activity because the transmit error counter
has reached its limiting value of FFh
0*
7 to 2
reserved
R
-
Reserved; do not modify. Read as logic 0
1
ES1
R
CAN controller 1 error status
1
The error warning limit has been exceeded
0*
0
ES0
R
CAN controller 0 error status
1
The error warning limit has been exceeded
0*