FlexRay Module Registers
1325
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
FlexRay Module
26.3.2 Communication Controller Registers
The FlexRay Communication Controller module allocates an address space of 2 Kbytes (0000h to 07FFh).
The registers are organized as 32-bit registers. 8/16-bit accesses are also supported. CPU access to the
message RAM is done through the input and output buffers. They buffer data to be transferred to and from
the message RAM under control of the message handler, avoiding conflicts between CPU accesses and
message reception / transmission. Alternatively to increase performance the Transfer Unit can be used for
transferring buffer data.
The test registers located on address 0010h and 0014h are writable only under the conditions.
The assignment of the message buffers is done according to the scheme shown in
. The
number N of available message buffers depends on the payload length of the configured message buffers.
The maximum number of message buffers is 128. The maximum payload length supported is 254 bytes.
The message buffers are separated into three consecutive groups; see
:
•
Static buffers - Transmit / receive buffers assigned to static segment
•
Dynamic buffers - Transmit / receive buffers assigned to static or dynamic segment
•
FIFO - Receive FIFO
The message buffer separation configuration can be changed in DEFAULT_CONFIG or CONFIG state
only by programming register MRC.
The first group starts with message buffer 0 and consists of static message buffers only. Message buffer 0
is dedicated to hold the startup / sync frame or the single slot frame, if the node transmits one, as
configured by SUCC1.TXST, SUCC1.TXSY, and SUCC1.TSM. In addition, message buffer 1 may be used
for sync frame transmission in case that sync frames or single-slot frames should have different payloads
on the two channels. In this case bit MRC.SPLM has to be programmed to 1 and message buffers 0 and 1
have to be configured with the key slot ID and can be (re)configured in DEFAULT_CONFIG or CONFIG
state only.
The second group consists of message buffers assigned to the static or to the dynamic segment.
Message buffers belonging to this group may be reconfigured during run time from dynamic to static or
vice versa depending on the state of MRC.SEC.
The message buffers belonging to the third group are concatenated to a single receive FIFO.
Figure 26-108. Message Buffer Assignment
Message Buffer 0
⇓
Static Buffers
Message Buffer 1
⇓
Dynamic Buffers
. . .
⇓
FIFO
Message Buffer N-1
Message Buffer N
provides a summary of the registers. The base address for the Communication Controller
registers is FFF7 C800h.