NXP Semiconductors MPC5644A Reference Manual page 1443

Peripheral
Bridge B
System
Memory
System Bus
The protocol engine has two transmitter units TxA and TxB and two receiver units RxA and RxB for
sending and receiving frames through the two FlexRay channels. The time control unit (TCU) is
responsible for maintaining global clock synchronization to the FlexRay network. The overall activity of
the PE is controlled by the sequencer engine (SEQ).
The CC host interface provides host access to the module's configuration, control, and status registers, as
well as to the message buffer configuration, control, and status registers. The message buffers themselves,
which contain the frame header and payload data received or to be transmitted, and the slot status
information, are stored in the FlexRay memory area.
The clock domain crossing unit implements signal crossing from the CHI clock domain to the PE clock
domain and vice versa, to allow for asynchronous PE and CHI clock domains.
The CC stores the frame header and payload data of frames received or of frames to be transmitted in the
FlexRay memory area. The application accesses the FlexRay memory area to retrieve and provide the
frames to be processed by the CC. In addition to the frame header and payload data, the CC stores the
synchronization frame related tables in the FlexRay memory area for application processing.
The FlexRay memory area is located in the system memory of the MCU. The CC has access to the FlexRay
memory area via its bus master interface (BMIF). The host provides the start address of the FlexRay
memory area within the system memory by programming the
(FR_SYMBADR). All FlexRay memory area related offsets are stored in offset registers. The physical
address pointer into the flexray memory area of the MCU system memory is calculated using the offset
values the FlexRay memory area base address.
Freescale Semiconductor
FlexRay
CHI
HIF
SEARCH
LUT
BCU
BMIF
Figure 33-1. FlexRay block diagram
MPC5644A Microcontroller Reference Manual, Rev. 6
FlexRay Communication Controller (FlexRay)
PE
config
SEQ
TxA
RxA
TCU
System Memory Base Address Register
FR_A_RX
FR_A_TX
FR_A_TX_EN
FR_B_RX
FR_B_TX
FR_B_TX_EN
FR_DBG[0]
FR_DBG[1]
FR_DBG[2]
FR_DBG[3]
1443