DS80C320-ENG datasheet(3/38 Pages) MAXIM

3 / 38 page

DS80C320/DS80C323 High-Speed/Low-Power Microcontrollers

3 of 38

Figure 1. Block Diagram

PIN DESCRIPTION

DIP

PLCC

TQFP

NAME

FUNCTION

VCC

+5V (+3V for DS80C323)

22, 23

16, 17

GND

Digital Circuit Ground

RST

Reset Input. The RST input pin contains a Schmitt voltage input to

recognize external active-high reset inputs. The pin also employs an

internal pulldown resistor to allow for a combination of wired OR

external reset sources. An RC is not required for power-up, as the device

provides this function internally.

XTAL2

XTAL1

Crystal Oscillator Pins. XTAL1 and XTAL2 provide support for

parallel-resonant, AT-cut crystals. XTAL1 acts also as an input in the

event that an external clock source is used in place of a crystal. XTAL2

serves as the output of the crystal amplifier.

PSEN

Program Store-Enable Output, Active Low. This signal is commonly

connected to external ROM memory as a chip enable. PSEN provides an

active-low pulse width of 2.25 XTAL1 cycles with a period of four

XTAL1 cycles. PSEN is driven high when data memory (RAM) is being

accessed through the bus and during a reset condition.

DS80C320/

DS80C323

DS80C320-ENG Datasheet(PDF) 3 Page - Maxim Integrated Products