A
ll
and more
abo
ut Sharp P
C-
1500 at http://www.PC-1500.info
2) Buzzer cir
cu
it
CJ.IT
OUT
10
I
SDO
1
\6
PC6
l:-,-.
--
~<1-
-...21
9
L..)
p 4
O
PB2~
1
~
1
--+--k1-__.
R
T
CMT
IN
Vee
BUZZER
a O
tt---.
The control signal CMT OUT
is
setnt out from the pin
SDO
of
lhe
1/0
port wich sounds the buzzer
in oombination with the low state
of
either the programmed output from the
1/0
port or CMT
IN
sent from the cassette tape deck.
3)
RAM
R/W signal circuit
R/W
RAJ.II
R/W
•
CPU
1-AD~l~O:.._l>l--_....,/W
:__,-
F:..:.:..--f:>t---t
6.6KO
TC5614PX2
pcs
4)
ON key double action preventive
circuit
16
Vee
OAP
202
560KO
BF
I -
-W"l'-_.
-
+-"-1
5
~
4
C........._
-
.Q
I
/0
PORT
SFI
--""
TC50HOOI
~""'-asr~·~39PF
...-----~
PS7
---'
P87
This
cir
cuit prevents writing if
ADIO
is
in
high
state during the
write mode (when
R/W
is
low).
This is
to
prevent wrong operation
when a specific key,
[!]
or
[I]
is
pushed without performing
"NEW
0 ENTER"
after battery replace-
ment.
This cir
cu
it consists
of
the Schmitt
circuit that prevents the possibility
of
setting the input flag
of
the
LH5B
11
1/0
porl
which
d e
pend~
on
how the
ON
key
is
pushed.
Do
not
sale this PDF
!!!
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