DS87C520 Maxim, DS87C520 Datasheet - Page 4

• Manufacturer Part Number: DS87C520
• Description: The DS87C520/DS83C520 EPROM/ROM high-speed microcontrollers are fast 8051-compatible microcontrollers
• Manufacturer: Maxim

Figure 1. Block Diagram
PIN DESCRIPTION
DIP
40
20
18
19
29
9
DS87C520/
DS83C520
1, 22, 23
PLCC
PIN
44
10
20
21
32
16, 17, 39
TQFP
38
14
15
26
4
XTAL2
XTAL1
NAME
PSEN
GND
RST
V
CC
DS87C520/DS83C520 EPROM/ROM High-Speed Microcontrollers
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Positive Supply Voltage. +5V
Digital Circuit Ground
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.
Crystal Oscillator Pins. XTAL1 and XTAL2 provide support for
parallel-resonant, AT-cut crystals. XTAL1 acts also as an input if
there is an external clock source in place of a crystal. XTAL2
serves as the output of the crystal amplifier.
Program Store-Enable Output. This active-low signal is
commonly connected to optional external ROM memory as a chip
enable. PSEN provides an active-low pulse and is driven high
when external ROM is not being accessed.
FUNCTION