DS87C520/DS83C520
DS87C530/DS83C520 BLOCK DIAGRAM
Figure 1
PIN DESCRIPTION
Table 1
DIP
40
20
9
PLCC
44
22,23,
1
10
TQFP
38
16, 17,
39
4
SIGNAL
NAME
V
CC
GND
RST
DESCRIPTION
V
CC
- +5V
GND
- Digital circuit ground.
RST - 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.
XTAL1, XTAL2 -
The 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.
18
19
20
21
14
15
XTAL2
XTAL1
29
32
26
PSEN
PSEN
-
Output.
The Program Store Enable output. This
signal is commonly connected to optional external ROM
memory as a chip enable.
PSEN
will provide an active
low pulse and is driven high when external ROM is not
being accessed.
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DALLAS [ DALLAS SEMICONDUCTOR ]
