EZ80F91MCU Datasheet, PDF (362/396 Pages) Zilog, Inc. – eZ80Acclaim-TM Flash Microcontrollers

eZ80F91 MCU
Product Specification
343
Table 227. Recommended Crystal Oscillator Specifications—1 MHz Operation
Parameter
Frequency
Resonance
Mode
Series Resistance (R_S)
Load Capacitance (C_L)
Shunt Capacitance (C₀)
Drive Level
Frequency
Dependent Value
1
Parallel
Fundamental
750
13
7
1
Units
MHz
Ohms
pF
pF
mW
Comments
Maximum
Maximum
Maximum
Maximum
Table 228. Recommended Crystal Oscillator Specifications—10 MHz Operation
Parameter
Frequency
Resonance
Mode
Series Resistance (R_S)
Load Capacitance (C_L)
Shunt Capacitance (C₀)
Drive Level
Frequency
Dependent Value
10
Parallel
Fundamental
35
30
7
1
Units
MHz
Ohms
pF
pF
mW
Comments
Maximum
Maximum
Maximum
Maximum
32 KHz Real-Time Clock Crystal Oscillator 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_IN or RTC_X_OUT pins. If oscillation does not occur, reduce the
values of capacitors C₁ and C₂ to decrease loading.
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.
PS019209-0504
PRELIMINARY
On-Chip Oscillators