Freescale Semiconductor FlexRay MFR4310, Reference Manual

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Device Overview
MFR4310 Reference Manual, Rev. 2
Freescale Semiconductor 47
2. Assert the external hard reset signal of the CC again.
2.6.3 Recommended Pullup/pulldown Resistor Values
As the IF_SEL[1:0] signals share pins with Physical Layer Interface signals, pullup and pulldown resistors
should be used for the selection. The recommended pullup/pulldown resistor values for the IF_SEL[1:0]
inputs are given in
Table 2-7 :
2.7 External Host Interface
The MFR4310 can be connected through three types of bus interface (see Section 2.6.2, “External Host
Interface Selection ” for information on how to select the host interface). The three types of microprocessor
interface are described below.
2.7.1 Asynchronous Memory Interface
Figure 2-5 shows how to connect the CC to a microcontroller using the AMI interface.
• Data exchange in AMI Mode is controlled by the CE#, WE# and OE# signals.
• The AMI interface is implemented as an asynchronous memory slave module, thus enabling fast
interfacing between the CC and a variety of microcontrollers.
• The AMI interface decodes its internal register addresses with the help of the chip select signal CE#
and the address lines A[12:1].
• The AMI interface accepts only aligned 16-bit read and 8-bit or 16-bit write transactions. The AMI
interface does not support 8-bit read accesses.
— The byte selects BSEL[1:0]#, the chip enable CE#, the output enable OE#, and the write enable
WE# are used to determine the type of access as shown in Table 2-8 .
Table 2-7. Recommended Pullup and Pulldown Resistor Values for IF_SEL[1:0] Inputs
IO, Regulator and analog supply level
( V
DD5
)
Pullup resistor
1
1
The listed values are calculated for the MFR4310-Physical Layer connection where no internal pullup/pulldown
resistors are assumed in the Electrical PHY at the TXD_BG1 and TXD_BG2 interface lines. If an Electrical PHY
device has internal pullup/pulldown resistors connected to these signals, then the external pullup/pulldown resistor
values must be recalculated to ensure that V
IL
requirements for pulldown resistors or V
IH
requirements for pullup
resistors for the chosen V
DD5
are met. See Section A.1.9, “I/O Characteristics ” for more details on V
IL
, V
IH
and V
DD5
.
Pulldown resistor
1
Units
3.3V 16 47 k
Ω
5V 10 47 k
Ω
Table 2-8. AMI Access Types
CE# WE# OE# BSEL1# BSEL0# Type of Access
0 0 0 X X Illegal
0 0 1 0 0 16-bit write to word address
1
0 0 1 0 1 8-bit write to even byte address
2