z16f2811 ZiLOG Semiconductor, z16f2811 Datasheet - Page 337

• Manufacturer Part Number: z16f2811
• Description: High Performance Microcontrollers
• Manufacturer: ZiLOG Semiconductor

On-Chip Oscillator
Operating Modes
Crystal Oscillator Operation
PS022006-0207
The products in the ZNEO Z16F Series feature an on-chip oscillator for use with external
crystals with frequencies from 32 kHz to 20 MHz. In addition, the oscillator supports
external RC networks with oscillation frequencies up to 4 MHz or ceramic resonators with
oscillation frequencies up to 20 MHz. This oscillator generates the primary system clock
for the internal ZNEO CPU and the majority of the on-chip peripherals. Alternatively, the
X
external clock generator is used, the X
When configured for use with crystal oscillators or external clock drivers, the frequency of
the signal on the X
internal clock divider). In RC operation, the system clock is driven by a clock divider
(divide by 2) to ensure 50% duty cycle.
The ZNEO Z16F Series products support four different oscillator modes:
•
•
•
•
The oscillator mode is selected through user-programmable option bits. For more informa-
tion, see
Figure 69
external fundamental mode, parallel-resonant crystal operating at 20 MHz. Recommended
20 MHz crystal specifications are provided in
optional and limits total power dissipation by the crystal. The printed circuit board layout
must add no more than 4 pF of stray capacitance to either the X
oscillation does not occur, it reduce the values of capacitors C1 and C2 to decrease
loading.
IN
On-chip oscillator configured for use with external RC networks (<4 MHz).
Minimum power for use with very low frequency crystals (32 kHz to 1.0 MHz).
Medium power for use with medium frequency crystals or ceramic resonators
(0.5 MHz to 10.0 MHz).
Maximum power for use with high frequency crystals or ceramic resonators
(8.0 MHz to 20.0 MHz).
input pin also accept a CMOS-level clock input signal (32 kHz to 20 MHz). If an
Option Bits
on page 324 illustrates a recommended configuration for connection with an
IN
on page 289.
input pin determines the frequency of the system clock (that is, no
P R E L I M I N A R Y
OUT
pin must be left unconnected.
Table 178
on page 324. Resistor R1 is
IN
Product Specification
or X
ZNEO
OUT
On-Chip Oscillator
™
pins. If
Z16F Series
323