IC80C54 Datasheet, PDF (10/22 Pages) Integrated Circuit Solution Inc – CMOS SINGLE CHIP 8-BIT MICROCONTROLLER

IC80C54
IC80C58
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 IC80C54/58 is a
single stage inverter, intended for use as a crystal-
controlled, positive reactance oscillator. 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 9). Examples
of how to drive the clock with external oscillator are shown
in Figure 10.
The crystal specifications and capacitance values (C1 and
C2 in Figure 9) are not critical. 20 pF to 30 pF can be used
in these positions at a 12 MHz to 24 MHz frequency with
good quality crystals. (For ranges greater than 24 MHz refer
to Figure 11.) 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
C1
XTAL1
GND
Figure 9. Oscillator Connections
NC
EXTERNAL
OSCILLATOR
SIGNAL
XTAL2
XTAL1
GND
Figure 10. External Clock Drive Configuration
10
Integrated Circuit Solution Inc.
MC003-0B