Radio Shack TRS-80 Service Manual page 19

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5
cs
In Ch;p sele.;t:
disable CLK and STB input and OAT A OUT output by the CS input.
All input/output are invalid unless CS is hjgh.
STB
l
'\
Lntern;il ~TB (comman<l
latch clock)
J
cs
CLK
]
'
J
Internal .CLK (40-bit serial clock)
OE
1
"\
J
Internal OE (gate input of OAT OUT)
6 OATALN
ln Oat a input signal ( 40-bit serial data)
7 GNO In OV
8
CLK
In 40-bit shift regi$ter clock (Data input/output is carried out in synchronization
withCLK .)
9
DATA
Out
Data output signal (40·bit serial data)
OUT
10
TP
Out Timer pulse output: to CO, Cl , C2 during command assignment.
II
OUT
In Output enable: input to control the output of DATA OUT.
ENABLE
12 XTAL In Basic
clock,
32.768kHz
13 XTAL In Same the above
14 Vl>D In
Source power input, connected to VGG
(4.7V).
6) Power supply circuit
The power supply is incorporated in a single resin molded IC that consists of the stabilizer circuit, temperature compensation
circuit. and bleeder circuit.
v
"'"'
.
int- (6>
' Po
'
L lX2
I4
-vr
t SS98
VGG
HI-MIC
2SB710
13
2Sll779
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ID
8
:
$
' r .R
-!-
AOAPT
Jae k
-::-u~t-S
-'
~
2SCI 623
~
Irr
t2
9
llf.O
\'Rl
7~
:
~1
3
-
X4
-
II
2
-:-
tO
6
1
~
VR2 ~
r- I
1
"T
...
,,,
5 2SJ84
•t
= ±
(;ND
Adjusting method
I. Apply 7.0
±
0.2V
DC.
at p-Oint· @ .
2 .
Turn
YR!
to read at VCC
4 .7
±
0.02
V DC from GND.
3. Turn VR2 to read at Vl>JSP 3.7
±
O.ot V DC from GNl>.
Supply vo!lagc: I .SV x 4 7V O.OSV
VCC:
4.7V
VCC :
4.7V
±0.02V
VDISP:
3.7V
t O .OIV
(In the case of25°C)
Do not sale this PDF !!!
- 16-
4. Adjusting condition is 25°C.