![](http://datasheet.mmic.net.cn/370000/PFR4200MAE40_datasheet_16728610/PFR4200MAE40_189.png)
Host Controller Interfaces
MFR4200 Data Sheet, Rev. 0
Freescale Semiconductor
189
will still indicate asserted IFLG bits for the message buffer that has been
included in the FIFO.
3.7
Host Controller Interfaces
The FlexRay communication controller can be connected and controlled by two types of microcontrollers
through the CC MCU interface. Two pins, IF_SEL0 and IF_SEL1, configure the interface for the type of
MCU. The MCU type is selected by IF_SEL0 and IF_SEL1 inputs as shown in
Table 3-19
.
When it leaves the hard reset state, the CC latches the values of the IF_SEL0 and IF_SEL1 signals and
configures the interface for the type of MCU accordingly. The CC does not analyze IF_SEL0 and IF_SEL1
after it has left the hard reset state (see
Section 3.9.1, “Hard Reset State
”).
NOTE
If the CC senses the unsupported mode on its IF_SEL pins, it stops all
internal operations, does not perform/respond on any host transactions,
stays in the configuration mode, and does not integrate into the
communication process. The following steps must be taken to select a
correct MCU interface mode.
1. IF_SEL0, IF_SEL1 must be set to the AMI or HCS12 mode.
2. The hard reset signal of the CC must be asserted again.
3.7.1
MFR4200 Asynchronous Memory Interface
The MFR4200 asynchronous memory interface is shown in
Figure 3-142
. This interface has the following
characteristics and features:
Data exchange in AMI mode is controlled by the CE#, WE# and OE# signals.
The MFR4200 AMI is implemented as an asynchronous memory slave module, thus enabling fast
interfacing between the CC and a variety of microcontrollers.
The MFR4200 AMI decodes its internal registers addresses with the help of the chip select signal
CE# and the address lines A[9:1].
NOTE
The address space from 0x0400 to 0x1FFF is reserved. Reading this address
space results in data 0x0000, while writing will not change the memory.
Reading or writing this address space will set the ILLADR bit in CHIER.
Table 3-19. FlexRay CC MCU Interface Configuration
Mode
IF_SEL0
IF_SEL1
Unsupported
0
0
HCS12
0
1
AMI
1
0
Unsupported
1
1