Z8F0113HJ005EG Datasheet, PDF (188/245 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F0823 Series
Product Specification
173
Internal Precision Oscillator
The internal precision oscillator (IPO) is designed for use without external components.
You can either manually trim the oscillator for a non-standard frequency or use the auto-
matic factory-trimmed version to achieve a 5.53 MHz frequency. The features of IPO
include:
• On-chip RC oscillator that does not require external components
• Output frequency of either 5.53MHz or 32.8kHz (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 accu-
racy is not required
Operation
An 8-bit trimming register, incorporated into the design, compensates for absolute varia-
tion of oscillator frequency. Once trimmed the oscillator frequency is stable and does not
require subsequent calibration. Trimming is performed during manufacturing and is not
necessary for you to repeat unless a frequency other than 5.53 MHz (fast mode) or
32.8 kHz (slow mode) is required. This trimming is done at +30°C and a supply voltage of
3.3 V, so accuracy of this operating point is optimal.
Power down this block for minimum system power. By default, the oscillator is configured
through the Flash Option bits. However, the user code can override these trim values, as
described in the Trim Bit Address Space section on page 151.
Select one of the two frequencies for the oscillator: 5.53 MHz and 32.8 kHz, using the
OSCSEL bits in the Oscillator Control chapter on page 169.
PS024315-1011
PRELIMINARY
Internal Precision Oscillator