EZ80F91MCU ZILOG [Zilog, Inc.], EZ80F91MCU Datasheet - Page 361

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

On-Chip Oscillators
PS019209-0504
Primary Crystal Oscillator Operation
The eZ80F91 features two on-chip oscillators for use with an external crystal. The
primary oscillator generates the system clock for the internal CPU and the major-
ity of the on-chip peripherals. Alternatively, the X
CMOS-level clock input signal. If an external clock generator is used, the X
pin should be left unconnected. The secondary oscillator can drive a 32 KHz crys-
tal to generate the time-base for the Real-Time Clock.
Figure 62 illustrates a recommended configuration for connection with an external
50MHz, 3
tions are provided in Tables 227 and 228. Printed circuit board layout should add
no more than 4 pF of stray capacitance to either the X
does not occur, the user should try removing C1 for testing and decreasing the
value of C
Figure 62. Recommended Crystal Oscillator Configuration—50 MHz Operation
C = 5 pF
1
X
IN
rd
2
-overtone, parallel-resonant crystal. Recommended crystal specifica-
by the estimated stray capacitance to decrease loading.
On-Chip Oscillator
(Third Overtone)
50 MHz Crystal
R = 100 KΩ
C = 10-15 pF
2
P R E L I M I N A R Y
C = .01-0.1 µF
3
X
OUT
L = 33 µH (± 10%)
IN
input pin can also accept a
IN
or X
Product Specification
OUT
pins. If oscillation
On-Chip Oscillators
eZ80F91 MCU
OUT
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