EasyManua.ls Logo

Yamaha FB-01 - Circuit Operation

Yamaha FB-01
31 pages
Save Page as PDF
Print Icon
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Loading...
■
CIRCUIT
OPERATION
1.
CPU
Clock
Circuit
A
1
2MHz
crystal
is
utilized
in
the
clock
generation
circuit
to
provide
the
clock
signal
for
the
CPU
and
sound
source.
A
6MHz
clock
signal
is
applied
to
the
clock
terminal
(pin
6
)
of
the
CPU
via
IC14,
a
divide
by
2
circuit.
2.
Sub-clock
Circuit
A
4MHz
crystal
is
utilized
in
the
clock
generation
circuit
to
provide
the
clock
signal
for
the
OPP,
DAC,
and
MIDI
cir¬
cuitry.
It
is
divided
down
to
500KHz
by
IC9
(74HC161)
and
applied
to
the
USART
(
M
PD71051)
and
OPP
(YM2164).
3.
Reset
Circuit
POWER
ON
RESET
is
generated
by
means
of
the
reset
cir¬
cuit
consisting
of
C87,
R37,
R72
and
ZD1.
The
circuit
is
also
connected
to
the
Chip
Enable
(CE)
signal
generation
circuit
for
the
RAM
battery
backup
function
so
that
the
RAM
data
is
protected
at
power
OFF.
4.
CPU,
ROM,
and
RAM
The
CPU
operates
on
the
basis
that
the
system
clock
is
about
6MHz.
For
this
reason,
the
access
time
of
the
bus
connecting
elements
such
as
ROM
and
RAM
must
be
faster
than
1
50nS.
The
ROM,
from
0000H
to
7FFFH,
is
for
the
voice
data
and
program
area
as
well
as
for
configuration
data
area.
The
RAM,
from
8000H
to
BFFFH,
is
used
as
the
area
for
storing
various
types
of
register
and
stack
information.
The
RAM
memory
is
also
utilized
for
storing
the
Configura¬
tion
Dat^,
and
the
User
Memory
Data.
This
RAM
area
is
battery
backed-up
in
order
to
save
or
hold
the
saved
data.
■
SYSTEM
BLOCK
DIAGRAM
IN
THROUGH
OUT
AUDIO
PRE
AMPUFIER
5.
The
Sound
Source
Circuit
This
circuit
consists
of
a
4-operator,
8-voices
FM
sound
source
(OPP
YM2164)
and
the
YM3012
DAC.
The
FM
sound
source
circuit
operates
according
to
the
data
from
the
CPU.
There
are
two
channels
for
the
audio
output
and
they
can
produce
different
voices.
6.
Switch
Scan
Circuit
This
circuit
scans
the
ON/OFF
states
of
the
8
switches
by
means
of
1C
1
8
(74HC244)
which
is
directly
connected
to
the
CPU
data
bus.
7.
MIDI
Circuit
The
USART
(
M
PD71051:
8251
compatible)
is
used
as
the
Transmitting
and
Receiving
device
of
the
MIDI
circuit.
It
conforms
to
the
MIDI
standard
VI.0.

Table of Contents

Other manuals for Yamaha FB-01

Preview: Owner's Manual
Owner's Manual67 pages

Related product manuals