LIN Controller (LINFlex)
MPC5606S Microcontroller Reference Manual, Rev. 7
Freescale Semiconductor 871
During reception, a Framing Error leads LINFlex to discard the current frame. LINFlex returns
immediately to idle state. An interrupt is generated if the FEIE bit in the LINIER is set.
During reception, a Checksum Error leads LINFlex to discard the received frame. LINFlex returns to idle
state. An interrupt is generated if the CEIE bit in the LINIER is set.
23.8.2.1.7 Overrun
Once the message buffer is full, the next valid message reception leads to an overrun and a message is lost.
The hardware sets the BOF bit in the LINSR to signal the overrun condition. Which message is lost
depends on the configuration of the RX message buffer:
• If the buffer lock function is disabled (LINCR1[RBLM] = 0) the last message stored in the buffer
is overwritten by the new incoming message. In this case the latest message is always available to
the application.
• If the buffer lock function is enabled (LINCR1[RBLM] = 0) the most recent message is discarded
and the previous message is available in the buffer.
23.8.2.2 Slave mode
In Slave mode the application uses the message buffer to handle the LIN messages. Slave mode is selected
when the MME bit in LINCR1 is cleared.
23.8.2.2.1 Data transmission (transceiver as publisher)
When LINFlex receives the identifier, the HRF bit in the LINSR is set and, if the HRIE bit in the LINIER
is set, an RX interrupt is generated. The software must read the received identifier in the BIDR, fill the
BDR registers, specify the data field length using the DFL[0:2] bits in the BIDR and trigger the data
transmission by setting the DTRQ bit in LINCR2.
One or several identifier filters can be configured for transmission by setting the DIR bit in the IFCRx
register(s) and activated by setting one or several bits in the IFER.
When at least one identifier filter is configured in transmission and activated, and if the received identifier
matches the filter, a specific TX interrupt (instead of an RX interrupt) is generated.
Typically, the application has to copy the data from SRAM locations to the BDAR. To copy the data to the
right location, the application has to identify the data by means of the identifier. To avoid this and to ease
the access to the SRAM locations, the LINFlex controller provides a Filter Match Index. This index value
is the number of the filter that matched the received identifier.
The software can use the index in the IFMI register to directly access the pointer that points to the right
data array in the SRAM area and copy this data to the BDAR (see
Figure 23-31).
Using a filter avoids the software having to configure the direction, the data field length and the checksum
type in the BDIR. The software fills the BDAR and triggers the data transmission by setting the DTRQ bit
in LINCR2.
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