Freescale Semiconductor FlexRay MFR4310, Reference Manual

Page: 140 / 268

FlexRay Module (FLEXRAYV4)
MFR4310 Reference Manual, Rev. 2
140 Freescale Semiconductor
3.4.3.6 Receive Shadow Buffer Configuration Data
Before frame reception into the individual message buffers can be performed, the receive shadow buffers
must be configured. The configuration data are provided by the
Receive Shadow Buffer Index Register
(RSBIR) . For each receive shadow buffer, the application provides the message buffer header index. When
the protocol is in the POC:normal active or POC:normal passive state, the receive shadow buffers are
under full FlexRay module control.
3.4.3.7 Receive FIFO Control and Configuration Data
This section describes the configuration and control data for the two receive FIFOs.
3.4.3.7.1 Receive FIFO Configuration Data
The FlexRay module provides two completely independent receive FIFOs, one per channel. Each FIFO
has its own set of configuration data. The configuration data are located in the following registers:
• Receive FIFO Start Index Register (RFSIR)
• Receive FIFO Depth and Size Register (RFDSR)
• Receive FIFO Message ID Acceptance Filter Value Register (RFMIDAFVR)
• Receive FIFO Message ID Acceptance Filter Mask Register (RFMIAFMR)
• Receive FIFO Frame ID Rejection Filter Value Register (RFFIDRFVR)
• Receive FIFO Frame ID Rejection Filter Mask Register (RFFIDRFMR)
• Receive FIFO Range Filter Configuration Register (RFRFCFR)
3.4.3.7.2 Receive FIFO Control Data
The application can access the receive FIFO at any time using the values provided in the Receive FIFO A
Read Index Register (RFARIR) and Receive FIFO B Read Index Register (RFBRIR) . To update the
Receive FIFO A Read Index Register (RFARIR) , the application must write 1 to the FIFO A Not Empty
Interrupt Flag FNEAIF in the Global Interrupt Flag and Enable Register (GIFER) . To update the Receive
FIFO B Read Index Register (RFBRIR) the application must write 1 to the FIFO B Not Empty Interrupt
Flag FNEBIF in the Global Interrupt Flag and Enable Register (GIFER) . As long as the FIFO is not empty,
each update increments the related read index. If the read index has reached the last FIFO entry, it wraps
back to the FIFO start index.
3.4.4 FlexRay Memory Layout
The FlexRay module supports a wide range of possible layouts for the FRM. Figure 3-100 shows an
example layout. The following set of rules applies to the layout of the FRM:
• The FRM is a contiguous region.
• The FRM size is 6 Kbytes.
• The FRM starts at modue address 0x800.
The FRM contains three areas: the message buffer header area , the message buffer data area , and the sync
frame table area . The areas are described in this section.