mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 468

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

Block Diagram
21.3 Block Diagram
The OSC module uses a crystal or resonator to generate three filtered oscillator clock
signals. Three clocks are output from OSC module: OSCCLK for MCU system,
OSCERCLK for on-chip peripherals, and OSC32KCLK. The OSCCLK can only work in
run mode. OSCERCLK and OSC32KCLK can work in low power modes. For the clock
source assignments, refer to the clock distribution information of this MCU.
Refer to the chip configuration chapter for the external reference clock source in this
MCU.
The following figure shows the block diagram of the OSC module.
21.4 OSC Signal Descriptions
The following table shows the user-accessible signals available for the OSC module.
Refer to signal multiplexing information for this MCU for more details.
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Range selections
Low Power config
OSC Clock Enable
OSC clock selection
STOP
ERCLKEN
EXTAL
Figure 21-1. OSC Module Block Diagram
MCF51JF128 Reference Manual, Rev. 2, 03/2011
Oscillator Circuits
EREFSTEN
XTAL
Preliminary
OSC_EN
Control and Decoding
logic
XTL_CLK
Counter
4096
E N
ERCLKEN
Freescale Semiconductor, Inc.
Mux
OSC_CLK_OUT
CNT_DONE_4096
OSC32KCLK
OSCERCLK
OSCCLK