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1.3 Pin description
Tables 1.3.1 to 1.3.3 list the pin description.
Table 1.3.1 Pin description (1)
Pin
Power supply
Vcc, Vss
CNVss
CNVss
______
Reset input
RESET
Clock input
X
IN
Clock output
X
OUT
_
Enable output
E
External data bus width
BYTE
selection input
Analog supply input
AVcc
AVss
Reference voltage input
V
REF
Name
Input/Output
Input
Input
Input
Output
Output
Input
Input
7751 Group User's Manual
Functions
Supply 5 V ±10 % to Vcc pin and 0 V to Vss pin.
This pin controls the processor mode.
[Single-chip mode] [Memory expansion mode]
Connect to Vss pin.
[Microprocessor mode]
Connect to Vcc pin.
The microcomputer is reset when supplying "L" level
to this pin.
These are I/O pins of the internal clock generating
circuit. Connect a ceramic resonator or quartz-crystal
oscillator between X
IN
external clock, the clock source should be input to X
pin and X
pin should be left open.
OUT
_
This pin outputs E signal.
Data/instruction code read or data write is performed
when output from this pin is "L" level.
[Memory expansion mode] [Microprocessor mode]
Input level to this pin determines whether the external
data bus has a 16-bit width or 8-bit width. The width
is 16 bits when the level is "L", and 8 bits when the
level is "H."
The power supply pin for the A-D converter. Externally
connect AVcc to Vcc pin.
The power supply pin for the A-D converter. Externally
connect AVss to Vss pin.
This is a reference voltage input pin for the A-D converter.
DESCRIPTION
1.3 Pin description
and X
pins. When using an
OUT
IN
1–5
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