Nxp Semiconductors UM10237 ユーザーズマニュアル

UM10237_2

© NXP B.V. 2008. All rights reserved.

 

[1]

Acceptance Filter Bypass Mode (AccBP): By setting the AccBP bit in the Acceptance Filter Mode Register, 
the Acceptance filter is put into the Acceptance Filter Bypass mode. During bypass mode, the internal state 
machine of the Acceptance Filter is reset and halted. All received CAN messages are accepted, and 
acceptance filtering can be done by software.

[2]

Acceptance Filter Off mode (AccOff): After power-upon hardware reset, the Acceptance filter will be in Off 
mode, the AccOff bit in the Acceptance filter Mode register 0 will be set to 1. The internal state machine of 
the acceptance filter is reset and halted. If not in Off mode, setting the AccOff bit, either by hardware or by 
software, will force the acceptance filter into Off mode.

[3]

FullCan Mode Enhancements: A FullCan mode for received CAN messages can be enabled by setting the 
eFCAN bit in the acceptance filter mode register.

The 10 bit section configuration registers are used for the ID look-up table RAM to indicate 
the boundaries of the different sections for explicit and group of CAN identifiers for 11 bit 
CAN and 29 bit CAN identifiers, respectively. The 10 bit wide section configuration 
registers allow the use of a 512x32 (2 kB) look-up table RAM. The whole ID Look-up Table 
RAM is only word accessible. All five section configuration registers contain APB 
addresses for the acceptance filter RAM and do not include the APB base address. A 
write access to all section configuration registers is only possible during the Acceptance 
filter off and Bypass modes. Read access is allowed in all acceptance filter modes.

0

AccOff

1

if AccBP is 0, the Acceptance Filter is not operational. All Rx 
messages on all CAN buses are ignored.

1

1

AccBP

1

All Rx messages are accepted on enabled CAN controllers. 
Software must set this bit before modifying the contents of any of 
the registers described below, and before modifying the contents 
of Lookup Table RAM in any way other than setting or clearing 
Disable bits in Standard Identifier entries. When both this bit and 
AccOff are 0, the Acceptance filter operates to screen received 
CAN Identifiers.

0

2

eFCAN

0

Software must read all messages for all enabled IDs on all 
enabled CAN buses, from the receiving CAN controllers.

0

1

The Acceptance Filter itself will take care of receiving and storing 
messages for selected Standard ID values on selected CAN 
buses. See 

31:3 -

Reserved, user software should not write ones to reserved bits. 
The value read from a reserved bit is not defined.

NA