External ROM
Mitsubishi microcomputers
M16C / 62 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
547
6.2 Pin Description
Tables 6.2.1 and 6.2.2 show the pin description.
Signal name
VCC, VSS
Power supply
input
Supply 2.7 to 5.5 V to the VCC pin. Supply 0 V to the VSS pin.
Function
AVCC
Analog power
supply input
This pin is a power supply input for the A-D converter. Connect this
pin to VCC.
Pin name
CNVSS
Connect this pin to VCC.
Input
XIN
XOUT
Clock input
Clock output
These pins are provided for the main clock generating circuit. Connect
a ceramic resonator or crystal between the XIN and the XOUT pins. To
use an externally derived clock, input it to the XIN pin and leave the
XOUT pin open.
Input
Output
BYTE
External data
bus width
select input
This pin selects the width of an external data bus. A 16-bit width is
selected when this input is “L”; an 8-bit width is selected when this
input is “H”. This input must be fixed to either “H” or “L”.
Input
VREF
Reference
voltage input
This pin is a reference voltage input for the A-D converter.
Input
P10 to P17
I/O port P1
This is an 8-bit CMOS I/O port. It has an input/output port direction
register that allows the user to set each pin for input or output
individually.
Input/output
I/O type
AVSS
This pin is a power supply input for the A-D converter. Connect this
pin to VSS.
Analog power
supply input
P40 to P47
I/O port P4
This is an 8-bit I/O port equivalent to P1.
Input/output
Output
CS0 to CS3,
A16 to A19
These pins output CS0–CS3 signals and A16–A19. CS0–CS3 are chip
select signals used to specify an access space. A16–A19 are 4 high-
order address bits.
Reset input
A “L” on this input resets the microcomputer.
Input
RESET
D0 to D7
When set as a separate bus, these pins input and output data (D0–D7).
Input/output
Data bus
D8 to D15
When set as a separate bus, these pins input and output data (D8–D15).
Input/output
Data bus
A0 to A7
These pins output 8 low-order address bits (A0–A7).
Output
Address bus
A0,
A1/D0 to
A7/D6
If the external bus is set as a 16-bit wide multiplexed bus, these pins
input and output data (D0–D6) and output address (A1–A7) separated
in time by multiplexing. They also output address (A0).
Output
Input/output
A0/D0 to
A7/D7
If the external bus is set as an 8-bit wide multiplexed bus, these pins
input and output data (D0–D7) and output 8 low-order address bits
(A0–A7) separated in time by multiplexing.
Input/output
Address bus/
data bus
A8/D7,
A9 to A15
If the external bus is set as a 16-bit wide multiplexed bus, these pins
input and output data (D7) and output address (A8) separated in time
by multiplexing. They also output address (A9–A15).
Input/output
Output
A8 to A15
These pins output 8 middle-order address bits (A8–A15).
Output
Address bus
Address bus/
data bus
Table 6.2.1. Pin Description (1)