EZ80F91MCU ZILOG [Zilog, Inc.], EZ80F91MCU Datasheet - Page 362

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

PS019209-0504
32 KHz Real-Time Clock Crystal Oscillator Operation
Table 227. Recommended Crystal Oscillator Specifications—1 MHz Operation
Table 228. Recommended Crystal Oscillator Specifications—10 MHz Operation
Figure 63 illustrates a recommended configuration for connecting the Real-Time
Clock oscillator with an external 32 KHz, fundamental-mode, parallel-resonant
crystal. The recommended crystal specifications are provided in Table 229. A
printed circuit board layout should add no more than 4 pF of stray capacitance to
either the RTC_X
values of capacitors C
An on-chip MOS resistor sets the crystal drive current limit. This configuration
does not require an external bias resistor across the crystal. An on-chip MOS
resistor provides the biasing.
Parameter
Frequency
Resonance
Mode
Series Resistance (R
Load Capacitance (C
Shunt Capacitance (C
Drive Level
Parameter
Frequency
Resonance
Mode
Series Resistance (R
Load Capacitance (C
Shunt Capacitance (C
Drive Level
IN
or RTC_X
S
S
L
L
0
0
)
)
)
)
)
)
1
and C
Frequency
Dependent Value
1
Parallel
Fundamental
750
13
7
1
Frequency
Dependent Value
10
Parallel
Fundamental
35
30
7
1
P R E L I M I N A R Y
OUT
2
to decrease loading.
pins. If oscillation does not occur, reduce the
Units
MHz
Ohms
pF
pF
mW
Units
MHz
Ohms
pF
pF
mW
Comments
Maximum
Maximum
Maximum
Maximum
Comments
Maximum
Maximum
Maximum
Maximum
Product Specification
On-Chip Oscillators
eZ80F91 MCU
343