IC80LV51 Datasheet, PDF (10/20 Pages) Integrated Circuit Solution Inc – CMOS SINGLE CHIP LOW VOLTAGE 8-BIT MICROCONTROLLER

IC80LV51
IC80LV31
Table 3. Status of the External Pins During Idle and Power-down Modes.
Mode
Idle
Idle
Power-down
Power-down
Memory
Internal
External
Internal
External
ALE PSEN PORT 0
1
1
Data
1
1
Float
0
0
Data
0
0
Float
PORT 1
Data
Data
Data
Data
PORT 2
Data
Address
Data
Data
PORT 3
Data
Data
Data
Data
On-Chip Oscillators
The on-chip oscillator circuitry of the IC80LV51/31 is a
single stage linear inverter, intended for use as a crystal-
controlled, positive reactance oscillator (Figure 8). In this
application the crystal is operated in its fundamental
response mode as an inductive reactance in parallel
resonance with capacitance external to the crystal (Figure
8). Examples of how to drive the clock with external
oscillator are shown in Figure 9.
The crystal specifications and capacitance values (C1 and
C2 in Figure 8) are not critical. 20 pF to 30 pF can be used
in these positions at a12 MHz to 24 MHz frequency with
good quality crystals. A ceramic resonator can be used in
place of the crystal in cost-sensitive applications. When a
ceramic resonator is used, C1 and C2 are normally selected
to be of somewhat higher values. The manufacturer of the
ceramic resonator should be consulted for recommendation
on the values of these capacitors.
C2
XTAL2
NC
C1
EXTERNAL
XTAL1
OSCILLATOR
SIGNAL
GND
XTAL2
XTAL1
GND
Figure 8. Oscillator Connections
Figure 9. External Clock Drive Configuration
Table 4. Recommended Value for C1, C2, R
Frequency Range
4 MHz - 24 MHz
C1
20 pF-30 pF
C2
20 pF-30 pF
R
Not Apply
10
Integrated Circuit Solution Inc.
MC005-0B