TC1784
System Control Unit (SCU)
User´s Manual
3-11
V1.1, 2011-05
32-bit SCU, V1.18
Operation on the Freerunning Mode does not require an input clock frequency of
f
OSC
.
The Freerunning Mode is automatically entered on a PLL VCO Loss-of-Lock event if bit
PLLCON0.OSCDISCDIS is cleared. This mechanism allows a fail-safe operation of the
PLL as in emergency cases still a clock is available.
The frequency of the Freerunning Mode
f
VCObase
is listed in the Data Sheet.
Note: Changing the system operation frequency by changing the value of the K2-Divider
has a direct coupling to the power consumption of the device. Therefore this has
to be done carefully.
Depending on the selected divider value of the K2-Divider the duty cycle of the clock is
selected. This can have an impact for the operation with an external communication
interface. The duty cycles values for the different K2-divider values are defined in the
Data Sheet.
Configuration and Operation of the Prescaler Mode
In Prescaler Mode, the PLL is running at the external frequency
f
OSC
and
f
PLL
is derived
from
f
OSC
only by the K1-Divider.
Figure 3-7
PLL Prescaler Mode Diagram
The output frequency is given by:
(3.6)
The Prescaler Mode is selected by the following settings
•
PLLCON0.VCOBYP = 1
The Prescaler Mode is entered when the following requirements are all together valid:
PLL Block
Osc.
WDG
K1-
Divider
f
PLL
f
K1
PLLCON 0.
VCOBYP
M
U
X
0
1
f
OSC
OSCCON.PLLLV
OSCCON.PLLHV
fPLL
fOSC
K1
--------------
=
Summary of Contents for TC1784
Page 1: ...User s Manual V1 1 2011 05 Microcontrollers TC1784 32 Bit Single Chip Microcontroller ...
Page 3: ...User s Manual V1 1 2011 05 Microcontrollers TC1784 32 Bit Single Chip Microcontroller ...
Page 950: ...TC1784 Direct Memory Access Controller DMA User s Manual 11 132 V1 1 2011 05 DMA V3 03 ...
Page 1949: ...TC1784 General Purpose Timer Array GPTA v5 User s Manual 21 297 V1 1 2011 05 GPTA v5 V1 14 ...
Page 2350: ...w w w i n f i n e o n c o m Published by Infineon Technologies AG Doc_Number ...