
Frequency Modulated Phase-Locked Loop (FMPLL)
PXN20 Microcontroller Reference Manual, Rev. 1
7-10
Freescale Semiconductor
7.4
Functional Description
The FMPLL module contains the frequency modulated phase lock loop (FMPLL), enhanced frequency
divider (ERFD), enhanced synthesizer control registers (ESYNCR1 and ESYNCR2), synthesizer status
register (SYNSR), and clock/PLL control logic. The block also contains a reference frequency pre-divider
controlled by the EPREDIV bits in the ESYNCR1. This enables the user to use a high frequency crystal
or external clock generator and obtain finer frequency synthesis resolution than would be available if the
raw input clock were used directly by the analog loop. For the remainder of this chapter, the term
“reference frequency” and the symbol F
ref
indicate the output of the pre-divider circuit. This is the clock
on which frequency multiplication is performed.
7.4.1
General
At reset, the system clock is driven by the internal oscillator (16 MHz IRC) and the module is in PLL Off
mode. After reset, software can change the PLL mode (see
Section 7.5.1, Clock Mode Selection
).
shows the PLL-clock to input-clock frequency relationships for the available clock modes.
Table 7-10. Output Divide Ratios
ERFD
Output Divide Ratio (ERFD+1)
00_0000
1
00_0001
2
00_0010
Invalid
00_0011
4 (default value for PXN20)
00_0100
Invalid
00_0101
6
00_0110
Invalid
00_0111
8
.
.
.
.
.
.
11_1100
Invalid
11_1101
62
11_1110
Invalid
11_1111
64
Table 7-11. Clock-Out vs. Clock-In Relationships
Clock Mode
Frequency Equation
Normal PLL Mode
F
sys
F
extal
EMFD
16
+
EPREDIV
1
+
ERFD
1
+
---------------------------------------------------------------------------
=
Содержание PXN2020
Страница 1: ...PXN20 Microcontroller Reference Manual Devices Supported PXN2020 PXN2120 PXN20RM Rev 1 06 2011...
Страница 42: ...PXN20 Microcontroller Reference Manual Rev 1 lxiv Freescale Semiconductor...
Страница 64: ...Introduction PXN20 Microcontroller Reference Manual Rev 1 1 22 Freescale Semiconductor...
Страница 112: ...Signal Description PXN20 Microcontroller Reference Manual Rev 1 3 44 Freescale Semiconductor...
Страница 118: ...Resets PXN20 Microcontroller Reference Manual Rev 1 4 6 Freescale Semiconductor...
Страница 162: ...Clocks Reset and Power CRP PXN20 Microcontroller Reference Manual Rev 1 6 30 Freescale Semiconductor...
Страница 182: ...Frequency Modulated Phase Locked Loop FMPLL PXN20 Microcontroller Reference Manual Rev 1 7 20 Freescale Semiconductor...
Страница 268: ...Boot Assist Module BAM PXN20 Microcontroller Reference Manual Rev 1 9 14 Freescale Semiconductor...
Страница 318: ...Interrupts and Interrupt Controller INTC PXN20 Microcontroller Reference Manual Rev 1 10 50 Freescale Semiconductor...
Страница 326: ...General Purpose Static RAM SRAM PXN20 Microcontroller Reference Manual Rev 1 11 8 Freescale Semiconductor...
Страница 372: ...e200z6 Core Z6 PXN20 Microcontroller Reference Manual Rev 1 13 8 Freescale Semiconductor...
Страница 412: ...e200z0 Core Z0 PXN20 Microcontroller Reference Manual Rev 1 14 14 Freescale Semiconductor...
Страница 460: ...Memory Protection Unit MPU PXN20 Microcontroller Reference Manual Rev 1 18 20 Freescale Semiconductor...
Страница 478: ...Error Correction Status Module ECSM PXN20 Microcontroller Reference Manual Rev 1 19 18 Freescale Semiconductor...
Страница 488: ...Software Watchdog Timer SWT PXN20 Microcontroller Reference Manual Rev 1 20 10 Freescale Semiconductor...
Страница 494: ...System Timer Module STM PXN20 Microcontroller Reference Manual Rev 1 21 6 Freescale Semiconductor...
Страница 821: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 Freescale Semiconductor 27 49...
Страница 822: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 27 50 Freescale Semiconductor...
Страница 926: ...Controller Area Network FlexCAN PXN20 Microcontroller Reference Manual Rev 1 29 42 Freescale Semiconductor...
Страница 990: ...Deserial Serial Peripheral Interface DSPI PXN20 Microcontroller Reference Manual Rev 1 30 64 Freescale Semiconductor...
Страница 1044: ...Enhanced Serial Communication Interface eSCI PXN20 Microcontroller Reference Manual Rev 1 31 54 Freescale Semiconductor...
Страница 1080: ...Cross Triggering Unit CTU PXN20 Microcontroller Reference Manual Rev 1 33 12 Freescale Semiconductor...
Страница 1134: ...Analog to Digital Converter ADC PXN20 Microcontroller Reference Manual Rev 1 34 54 Freescale Semiconductor...
Страница 1150: ...IEEE 1149 1 Test Access Port Controller JTAGC PXN20 Microcontroller Reference Manual Rev 1 35 16 Freescale Semiconductor...
Страница 1257: ...Nexus Development Interface NDI PXN20 Microcontroller Reference Manual Rev 1 Freescale Semiconductor 36 107...
Страница 1258: ...Nexus Development Interface NDI PXN20 Microcontroller Reference Manual Rev 1 36 108 Freescale Semiconductor...
Страница 1376: ...Memory Map PXN20 Microcontroller Reference Manual Rev 1 A 118 Freescale Semiconductor...