mfr4200 Freescale Semiconductor, Inc, mfr4200 Datasheet - Page 160

• Manufacturer Part Number: mfr4200
• Description: Flexray Communication Controllers
• Manufacturer: Freescale Semiconductor, Inc

MFR4200 FlexRay Communication Controller
3.5
3.5.1
The FlexRay MFR4200 uses a partial double buffering technique to provide a scheme for buffer handling.
Using this technology, buffers can be configured as single/double transmit message buffers, or partially, as
single and as double transmit message buffers, as required by the application. At the same time, the
FlexRay MFR4200 offers enhanced:
The new buffer handling and operations scheme has the following features.
All features are described in more detail in the following sections.
3.5.2
The FlexRay CC memory map including buffers locations is shown in
The host accesses CC internal buffer data, configuration, and status fields only through appropriate active
receive/ transmit/FIFO message buffers by using the locking mechanism. Shadow receive message buffers
serve the host accesses to message buffers while the CC continues to receive/transmit frames.
160
•
•
•
•
•
•
•
•
•
•
Active window mechanism
Interrupt service
Buffer access scheme
The host and the CC have independent access to all the buffers. Therefore, the host can access
receive/transmit message buffers almost instantly while the CC transmits/receives frames.
The host can configure receive/transmit buffers in the configuration state and partially, during
normal operation (see
The buffer configuration map is flexible.
The buffer mechanism supports multiple locking/unlocking of the same transmit buffer, without
committing for transmission.
The host can commit a transmit message buffer for transmission without update or with only partial
update of its data fields.
The host explicitly controls every transmit buffer commitment for transmission.
The host can access a receive message buffer while the CC receives a new frame for that buffer.
Message Buffer Handling and Operations
Introduction
Buffer Map
•
•
To disable frame ID filtering, set the frame ID value to 0x0000 and the
frame ID mask to 0xFFFF. (No semantically valid frame ID will be
rejected.)
To disable message ID filtering, set the message ID mask to 0x0000 (all
message IDs are accepted).
Section 3.5.5, “Buffer Reconfiguration in the Normal State of
MFR4200 Data Sheet, Rev. 0
Table
3-1.
Freescale Semiconductor
Operation”).