Marantz DV4300, Service Manual

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41
U501:W78LE51
VDD 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
39
40
34
35
36
37
38
30
31
32
33
26
27
28
29
21
22
23
24
25
P0.0, AD0
P0.1, AD1
P0.2, AD2
P0.3, AD3
P0.4, AD4
P0.5, AD5
P0.6, AD6
P0.7, AD7
EA
ALE
PSEN
P2.5, A13
P2.6, A14
P2.7, A15
P2.0, A8
P2.1, A9
P2.2, A10
P2.3, A11
P2.4, A12
P1.0
P1.2
P1.3
P1.4
P1.5
P1.6
RXD, P3.0
TXD, P3.1
P1.7
RST
INT0, P3.2
INT1, P3.3
T0, P3.4
T1, P3.5
WR, P3.6
RD, P3.7
XTAL1
XTAL2
VSS
P1.1
SYMBOL DESCRIPTIONS
EA
EXTERNAL ACCESS ENABLE : This pin forces the processor to execute out of
external ROM. It should be kept high to access internal ROM. The ROM address and
data will not be presented on the bus if EA pin is high and the program counter is
within on-chip ROM area.
PSEN PROGRAM STORE ENABLE : PSEN enables the external ROM data onto the Port 0
address/ data bus during fetch and MOVC operations. When internal ROM access is
performed, no PSEN strobe signal outputs from this pin.
ALE ADDRESS LATCH ENABLE : ALE is used to enable the address latch that separates
the address from the data on Port 0.
RST
RESET : A high on this pin for two machine cycles while the oscillator is running resets
the device.
XTAL1 CRYSTAL1 : This is the crystal oscillator input. This pin may be driven by an external
clock.
XTAL2
CRYSTAL2 : This is the crystal oscillator output. It is the inversion of XTAL1.
V
SS
GROUND : Ground potential
V
DD
POWER SUPPLY : Supply voltage for operation.
P0.0
−
P0.7 PORT 0 : Port 0 is a bi-directional I/O port which also provides a multiplexed low order
address/data bus during accesses to external memory. The Port 0 is also an open-drain
port and external pull-ups need to be connected while in programming.
P1.0
−
P1.7
PORT 1 : Port 1 is a bi-directional I/O port with internal pull-ups. The bits have alternate
functions which are described below:
T2(P1.0): Timer/Counter 2 external count input
T2EX(P1.1): Timer/Counter 2 Reload/Capture control
P2.0
−
P2.7
PORT 2 : Port 2 is a bi-directional I/O port with internal pull-ups. This port also provides
the upper address bits for accesses to external memory.
P3.0
−
P3.7 PORT 3 : Port 3 is a bi-directional I/O port with internal pull-ups. All bits have alternate
functions, which are described below:
RXD(P3.0) : Serial Port receiver input
TXD(P3.1) : Serial Port transmitter output
INT0 (P3.2) : External Interrupt 0
INT1(P3.3) : External Interrupt 1
T0(P3.4) : Timer 0 External Input
T1(P3.5) : Timer 1 External Input
WR (P3.6) :External Data Memory Write Strobe
RD (P3.7) : External Data Memory Read Strobe
P4.0
−
P4.3
PORT 4: Another bit-addressable bidirectional I/O port P4. P4.3 and P4.2 are alternative
function pins. It can be used as general I/O port or external interrupt input sources
(INT2 /INT3 ).