ia186em Innovasic Semiconductor Inc., ia186em Datasheet - Page 45

• Manufacturer Part Number: ia186em
• Description: 8-bit/16-bit Microcontrollers
• Manufacturer: Innovasic Semiconductor Inc.

IA186EM/IA188EM
8-Bit/16-Bit Microcontrollers
4.2
A phase-lock-loop (PLL) and a second programmable system clock output (clkoutb) are included
in the clock and power management unit. The internal clock is the same frequency as the crystal
but with a duty cycle of 45% to 55 %, as a worst case, generated by the PLL obviating the need
for an x2 external clock. A POR resets the PLL (see Figure 8).
4.3
If required, the internal oscillator can be driven by an external clock source that should be
connected to x1, leaving x2 unconnected.
The clock outputs clkouta and clkoutb may be enabled or disabled individually (Power-Save
Control register (PDCON) Bits [11–8]). These clock control bits allow one clock output to run
at PLL frequency and the other to run at the power-save frequency (see Figure 9).
Clock and Power Management
System Clocks
C
C
1
2
®
Crystal
Figure 8. Crystal Configuration
UNCONTROLLED WHEN PRINTED OR COPIED
x1
x2
Page 45 of 145
IA211050831-16
IA186EM/
IA188EM
Recommended
range of values for
C
C
C
1
1
2
and C
= 15 pF ±20%
= 22 pF ±20%
2
are:
December 24, 2008
http://www.Innovasic.com
Customer Support:
Data Sheet
1-888-824-4184