
Chapter 13 FlexRay Communication Controller (FLEXRAY)
MC9S12XF - Family Reference Manual, Rev.1.19
460
Freescale Semiconductor
The FlexRay block stores the frame header and payload data of frames received or of frames to be
transmitted in the FRM. The application accesses the FRM to retrieve and provide the frames to be
processed by the FlexRay block. In addition to the frame header and payload data, the FlexRay block stores
the synchronization frame related tables in the FRM for application processing.
The FlexRay Memory is located in the system memory of the MCU. The FlexRay block has access to the
FRM via its bus master interface (BMIF). The host provides the start address of the FRM window within
offset registers. The physical address pointer into the FRM window of the MCU system memory is
calculated using the offset values the FlexRay Memory base address.
NOTE
The FlexRay block does not provide a memory protection scheme for the
FlexRay Memory.
13.1.5
Features
The FlexRay block provides the following features:
implementation
compliant bus driver interface
single channel support
— FlexRay Port A can be congured to be connected either to physical FlexRay channel A or
physical FlexRay channel B.
FlexRay bus data rates of 10 Mbit/s, 8 Mbit/s, 5 Mbit/s, and 2.5 Mbit/s supported
internal oscillator or internal PLL clocking of the protocol engine
32 congurable message buffers with
— individual frame ID ltering
— individual channel ID ltering
— individual cycle counter ltering
message buffer header, status and payload data stored in dedicated FlexRay Memory
— allows for exible and efcient message buffer implementation
— consistent data access ensured by means of buffer locking scheme
— application can lock multiple buffers at the same time
size of message buffer payload data section congurable from 0 up to 254 bytes
two independent message buffer segments with congurable size of payload data section
— each segment can contain message buffers assigned to the static segment and message buffers
assigned to the dynamic segment at the same time
zero padding for transmit message buffers in static segment
— applied when the frame payload length exceeds the size of the message buffer data section