z8f083a ZiLOG Semiconductor, z8f083a Datasheet - Page 167

• Manufacturer Part Number: z8f083a
• Description: High-performance 8-bit Microcontrollers
• Manufacturer: ZiLOG Semiconductor

Internal Precision Oscillator
Operation
PS026308-1207
The internal precision oscillator (IPO) is designed for use without external components.
You either manually trim the oscillator for a non-standard frequency or use the automatic
factory trimmed version to achieve a 20 MHz frequency with
45%~55% duty
Maximum startup time of IPO is 25 us. IPO features include:
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•
•
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The internal oscillator is an RC relaxation oscillator with minimized sensitivity to power
supply variation. By using ratio tracking thresholds, the effect of power supply voltage is
cancelled out. The dominant source of oscillator error is the absolute variance of chip level
fabricated components, such as capacitors. An 8-bit trimming register, incorporated into
the design, compensates for absolute variation of oscillator frequency. Once trimmed the
oscillator frequency is stable and does not require subsequent calibration. Trimming was
performed during manufacturing and is not necessary for you to repeat unless a frequency
other than 20 MHz (FAST mode) or 119 kHz (SLOW mode) is required.
Power-down this block for minimum system power.
By default, the oscillator is configured through the Flash option bits. However, the user
code overrides these trim values as described in
Select one of two frequencies for the oscillator: 20 MHz and 119 kHz, using the OSCSEL
bits in the
On-chip RC oscillator that does not require external components
Output frequency of either 20 MHz or 119 kHz (contains both a FAST and a SLOW mode)
Trimming possible through Flash option bits with user override
Elimination of crystals or ceramic resonators in applications where high timing accuracy
is not required
Oscillator Control
cycle
over the operating temperature and supply voltage of the device.
on page 145.
Trim Bit Address Space
Z8 Encore!
± 4%
Product Specification
Internal Precision Oscillator
accuracy and
®
on page 124.
F083A Series
155