EZ80F91MCU ZILOG [Zilog, Inc.], EZ80F91MCU Datasheet - Page 53

• Manufacturer Part Number: EZ80F91MCU
• Description: eZ80Acclaim-TM Flash Microcontrollers
• Manufacturer: ZILOG [Zilog, Inc.]

PS019209-0504
50 Mhz while the X
pins can be driven by a crystal circuit.
Crystals recommended by ZiLOG are defined to be a 50 Mhz–3 overtone circuit or
1–10 MHz range fundamental for PLL operation. For details, refer to the
Oscillators
Real Time Clock.
either the on-chip 32768 Hz crystal oscillator or a 50/60 Hz power-line frequency
input. While intended for timekeeping, the RTC 32 KHz oscillator can be selected
as an SCLK. RTC_V
RTC operation in the event of loss of line power when a battery is provided. For
details, refer to the
PLL Clock.
in the 1 MHz to 10 MHz range to generate an SCLK up to 50 MHz. For details, refer
to the
SCLK Source Selection Example
If an application must run the eZ80F91 device at 40 MHz, the following solutions
are possible:
•
•
•
Use a 40 MHz–3rd overtone crystal (not recommended due to its weak funda-
mental rating)
Use a 40 MHz can oscillator (expensive)
Use an 8 MHz fundamental two-pin crystal and program the internal PLL with
a multiplier of five to achieve 40 MHz (inexpensive).
Phase-Locked Loop
section on page 342.
The eZ80F91 internal PLL driven by external crystals or can oscillators
An internal 32 KHz real-time clock crystal oscillator driven by
OUT
On-Chip Oscillators
DD
pin is unconnected. In the other mode, the X
and RTC_V
P R E L I M I N A R Y
section on page 320.
SS
provide an isolated power supply to ensure
section on page 342.
Product Specification
Architectural Overview
eZ80F91 MCU
IN
and X
On-Chip
OUT
34