¡ Semiconductor
MSM65516/65P516
PIN DESCRIPTIONS
Basic Functions
Function
Power
Supply
Oscillation
Symbol
V
DD
GND
OSC0
OSC1
RESET
EA
Control
RD
ALE
PORT 0
O
O
I/O
Type
—
—
I
O
I
I
+5V power supply
0V digital ground
Crystal oscillator input/external clock input
Crystal oscillator output
System reset input (program starts from address 0040H);
internal pull-up resistance
Program memory select input pin.
"L" level input for external program memory; "H" level input for internal
program memory.
Read strobe signal during external memory access
Address latch signal during external memory access
8-bit Input-output port
During external memory access, becomes address/data bus for address
output, instruction fetch or data read/write along with ALE,
RD
and
WR
pins.
8-bit Input-output port
Address bus during external memory access
8-bit Input-output port
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4. Secondary functions shown in following table
are added for ports 2 and 3.
Description
PORT 1
Port
PORT 2
PORT 3
PORT 4
PORT 5
PORT 6
I/O
I/O
I
8-bit Input port
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