MITSUBISHI MICROCOMPUTERS
7477/7478 GROUP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
BUILT-IN PROM TYPE MICROCOMPUTERS
PIN DESCRIPTION
Input/
output
Pin
Mode
Name
Functions
VCC,VSS
Single-chip Power source
/EPROM
Apply voltage of 2.7 to 5.5 V to VCC and 0 V to VSS.
AVSS
Single-chip Analog power
Ground level input pin for A-D converter. Same voltage as VSS is applied.
(Note 1)
/EPROM
source
RESET
Single-chip Reset input
Input To enter the reset state, the reset input pin must be kept at a “L” for 2µs or more
(under normal VCC conditions).
EPROM
Reset input
Input
Connect to VSS.
XIN
Single-chip Clock input
/EPROM
Input These are I/O pins of internal clock generating circuit for main clock. To control
generating frequency, an external ceramic or a quartz crystal oscillator is con-
nected between the XIN and XOUT pins. If an external clock is used, the clock
Output source should be connected the XIN pin and the XOUT pin should be left open.
Feedback resistor is connected between XIN and XOUT.
XOUT
VREF
Single-chip Clock output
/EPROM
Single-chip Reference
voltage input
Input Reference voltage input pin for the A-D converter.
EPROM
Select mode
Input
I/O
VREF works as CE input.
P00 – P07
P10 – P17
Single-chip I/O port P0
Port P0 is an 8-bit I/O port. The output structure is CMOS output. When this port
is selected for input, pull-up transistor can be connected in units of 1-bit and a
key on wake up function is provided.
EPROM
Data I/O D0–D7
I/O
I/O
Port P0 works as an 8-bit data bus (D0 to D7).
Single-chip I/O port P1
Port P1 is an 8-bit I/O port. The output structure is CMOS output. When this port
is selected for input, pull-up transistor can be connected in units of 4-bit. P12 and
P13 are in common with timer output pins T0, T1. P14, P15, P16 and P17 are in
common with serial I/O pins RxD, TxD, SCLK, SRDY, respectively.
EPROM
Address input
A4–A10
Input
Input
P11 to P17 works as the 7-bit address input (A4 to A10). P10 must be opened.
P20 – P27
(Note 2)
Single-chip Input port P2
Port P2 is an 8-bit input port. This port is in common with analog input pins IN0 to IN7.
EPROM
Address input
A0–A3
Input P20 to P23 works as the lower 4-bit address input (A0 to A3).
P24 to P27 must be opened.
P30 – P33
Single-chip Input port P3
Input
Input
Port P3 is a 4-bit input port. P3
0
and P3
1
are in common with external interrupt in-
, CNTR
put pins INT , INT and P3 , P3
0
1
2
3
are in common with timer input pins CNTR
0
1.
EPROM
Address input
A11, A12 Select
mode VPP input
P30, P31 works as the 2-bit address input (A11, A12).
P32 works as OE input. Connect to P33 to VPP when programming or verifying.
P40 – P43
(Note 3)
Single-chip I/O port P4
I/O
Port P4 is a 4-bit I/O port. The output structure is CMOS output. When this port is
selected for input, pull-up transistor can be connected in units of 4-bit.
EPROM
Address input
A13, A14
Input
P40 and P41 works as the higher 2-bit address input (A13, A14).
P42 and P43 must be opened.
P50 – P53
(Note 4)
Single-chip Input port P5
Input Port P5 is a 4-bit input port and pull-up transistor can be connected in units of 4-
bit. P50, P51 are in common with input/output pins of clock for clock function XCIN,
XCOUT. When P50, P51 are used as XCIN, XCOUT, connect a ceramic or a quartz
crystal oscillator between XCIN and XCOUT. If an external clock input is used, con-
nect the clock input to the XCIN pin and open the XCOUT pin. Feedback resistor is
connected between XCIN and XCOUT pins.
EPROM
Notes 1 : AVSS for M37478M4/M8/E8-XXXFP.
Open.
2 : Only P20–P23 (IN0–IN3) 4-bit for the 7477 group.
3 : Only P40 and P41 2-bit for the 7477group.
4 : This port is not included in the 7477 group.
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MITSUBISHI [ Mitsubishi Group ]
