mfr4200 Freescale Semiconductor, Inc, mfr4200 Datasheet - Page 169

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

During the internal initialization procedure, the host must not access any CC registers except MNR (see
Section 3.2.3.1.3, “Magic Number Register
initialization procedure.
Message Buffer Configuration Principles
An example of buffer configuration is presented in
Freescale Semiconductor
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— CFG = 0
— DATUPD = 0
After a hard reset, all message buffers are initialized as receive message buffers disabled for receive
operations (frame ID=0x0). In normal operation, any buffers not configured by the host, during the
configuration state, remain receive message buffers disabled for receive operations.
If a configuration includes FIFO buffers (see
FIFO starts from message buffer 0 (see
Buffers of different types can be mixed in the buffer map (receive, single transmit, double transmit,
and transmit/receive message buffers that are not used for transmit/receive operations (frame
ID=0x0)) (see
FIFO buffers:
— must be placed in a continuous subset of message buffers that is uninterrupted by buffers of
— the number of message buffers reserved for the FIFO is determined by the FIFO size register
The host part buffer of a double transmit message buffer must have an odd number.
The number of the CC part buffer of a double transmit message buffer must be its host part buffer
+ 1.
During the configuration state, only the host part buffer of a double transmit message buffer is
available for host read/write configuration operations. Hence, the host part buffer configuration is
used for both parts of a double transmit message buffer. The configuration of the host part buffer
overwrites the configuration of the CC part buffer.
Only transmit message buffers can be configured as double transmit message buffers.
FIFO and receive message buffers are always single buffers.
CC part buffers of double transmit message buffers have read-only host access. CC part buffers
cannot be locked; consequently, the host can read only the BUFCSnR and CCFnR registers of the
buffer.
other types
value (see
Section 3.2.3.7.1, “FIFO Size Register
Figure
3-134).
MFR4200 Data Sheet, Rev. 0
(MNR)”), which acknowledges the finish of the internal
Figure
Figure
Section 3.2.3.7.1, “FIFO Size Register
3-134).
3-134.
(FSIZR)”)
Message Buffer Handling and Operations
(FSIZR)”), the
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