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External 4/10 MHz Output Clock
MFR4200 Data Sheet, Rev. 0
Freescale Semiconductor
197
3.8
External 4/10 MHz Output Clock
A continuous external 4/10 MHz output clock signal is provided by the CC on the CLKOUT pin. This
signal is always active after power-up of the CC in all CC states including the hard reset state. The
CLKOUT signal is disabled during the internal power-on and low voltage reset procedures (refer to
Chapter 5, “Clocks and Reset Generator
” for more information).
The output frequency of the CLKOUT signal is selected by the CLK_S0, CLK_S1 input pins, in
accordance with
Table 3-22
.
NOTE
For information on CLKOUT stabilization timing parameters, refer to
Appendix A, “Electrical Characteristics
”.
3.9
Communication Controller States
3.9.1
Hard Reset State
Protocol Operation Control:
Initiate hardware state.
During this state, the CC initializes all internal registers to their specified hard reset default state (see
Section 3.2.2, “Register Map Summary
”).
In the hard reset state:
All the operation with protocol state machine are stopped.
There is no transmission or reception on the FlexRay bus.
There is no clock synchronization running.
The CC host interface is stopped.
The CC analyzes the input signals on the two pins IF_SEL0 and IF_SEL1 while leaving the hard
reset state to configure the interface for the type of MCU (see
Section 3.7, “Host Controller
Interfaces
”).
The CC enters the hard reset state:
According to the state of the hard reset pin (see
Section 5.2.2, “Reset Generation and CLKOUT
Control
”).
Table 3-22. CLKOUT Frequency Selection
Pin
CLKOUT Function
CLK_S0
CLK_S1
0
0
4 MHz output
1
0
10 MHz output
0
1
40 MHz output
1
1
Disabled (CLKOUT output is “0“)