PXD20RM Datasheet, PDF (967/1628 Pages) Freescale Semiconductor, Inc – PXD20 Microcontroller

this and to ease the access to the RAM locations, the LINFlexD controller provides a Filter Match Index.
This index value is the number of the filter which matched the received identifier.
The software can use the index in the IFMI register to directly access the pointer which points to the right
data array in the RAM area and copy this data from the BDRL and BDRM registers to the RAM (see
Figure 27-10).
Using a filter avoids the software reading the ID value in the BIDR register, and configuring the direction,
the data field length and the checksum type in the BIDR register.
If LINFlexD cannot provide enough RX identifier filters to handle all identifiers the software has to
receive the data for, then a filter can be configured in mask mode (refer to Section 27.7.3, Slave mode with
identifier filtering) in order to manage several identifiers with one filter only.
27.7.2.3 Data discard
When LINFlexD receives the identifier, an RX interrupt is generated. If the received identifier does not
concern the node, the software must set LINCR2[DDRQ]. LINFlexD returns to idle state.
27.7.2.4 Error detection and handling
Table 27-2 lists the errors detected in Slave mode and the LINFlexD controller’s response to these errors.
Table 27-2. Errors in Slave mode
Error
Bit error
Framing error
Checksum error
Header error
Description
LINFlexD response to error
During transmission, the value read back
from the bus differs from the transmitted
value
• Stops the transmission of the frame after
the corrupted bit
• Generates an interrupt if LINIER[BEIE] is
set
• Returns to idle state
A dominant state has been sampled on the
stop bit of the currently received character
(sync field, identifier, or data field)
If encountered during reception:
• Discards the current frame
• Generates an interrupt if LINIER[FEIE] is
set
• Returns immediately to idle state
The computed checksum does not match the If encountered during reception:
received checksum
• Discards the received frame
• Generates an interrupt if LINIER[CEIE] is
set
• Returns to idle state
An error occurred during header reception If encountered during header reception, a
(break delimiter error, inconsistent sync field, break field error, an inconsistent sync field, or
header timeout)
a timeout:
• Discards the header
• Generates an interrupt if LINIER[HEIE] is
set
• Returns to idle state
Freescale Semiconductor
PXD20 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
27-11