
ervlce
TRSa)
Pocket Comput9f and Cassette Interface
C8t111og
Number·
2&3501
.
26-3503
-
CUSTOM
MAMfACTIJlEO
FOR
RAIJIO
SHACK2A
DIVISION
OF
TANDY
CORPORATION

-
--
TABLE
1.Sf'l'ClI'ICA1lOl't5 -•.,2
IIUX:..I.IIAGUM • • • • •• • . • • •• • • •• • . • • . • . • • • • • • . • • •• • . • . • • •.•• •
J.
lSI
SIGNAL
.,
IER*E
S.
CASSUTE TAft; A
4.
CASUTTIOf'f:llAno"
1
CtECJI:
•
OK\nT
0,
0,0,
Eq
LrP.c.I.
l'-lJOJ
}6.UOJ •.c.'. .
9.
PARTS
10
PARTS
O£5CaIP'T1(lI\iS
SllVlONC
I'ROCilUM •
D1ACllAM'....TSA SK20IAU
'
-~
t
,.c.L
_.
•••....•..
tr«UfACl!
•••••.•
• • • . • . .
.
...........•....•
tiIIr-..............
UST
FOR
}t.J501
UST FOIl
26J50J
Of
CONTENTS
••
-.
.•.•••.••....•.•••.•.••••••.•••..••••
, .
•••.••
----
•...•
.....................•..
P(l5Ill(lIIl
••••••••.•.••.••••••
------.
........ .
..
.....•..............................
. u
_
......•
_.
_
_ "
.
.•
I
10
14
14
If>
::
ZI
n
24
21
:n
ZS
~

Sy.tem
Th.
I
2.
J.
4.
I.
~.
7,ln.."",ITC4l)6<Jijp,IJ
S.
9.
10.
11. Cty"ol(CSlIlS60\
oonhgu••t,on
')'1to'"
ronu,"
CPUI1SC4Jln)"
CPliU(SC43I1S/,
4K"'I'
RA!ot
ITelI14P"
[\",oy
,1,,1'
($C4JI
lAND
p,dTC41111UIlP.
2ANLJ<Olqu.:401~ijV,
Q,
...
d
....
>loa
S..Ilot.
LCD(l4<1i&1'
1_th........mblo<:I<
of
,h.
I
,J
)olul,ipI.",
FHot
<too
"or
fo~""",,~
,3••
lCll)
,0mP">"'"'~
3\
mh
b.~''''
I)
I)
(TC~8I')
d.-gr.ml
RA.\t\
Brief overview of CPU I and
CPU
I
K.,.
In"",
",",in.
A't.fto",.dpmm'
0...
","r.KI1cm
oddlli""ol 1""001'0"'"",
1',,,,,.,,,
Ca",,,.
hi,,,,,
h"""'''n
I
•
lb.
CPI} I
1\1.""""'".....
d_
f",I••
,_,.".
".do_t).Of101,,1'''' tho
Ih.
ioof",,,,,,1cm
'm
in
ly
,,,,,;v
,..n...,
do
..
o<>t
pl"Ol"f
....
II"',
to
'"'I,,"n<o
",",.,.
dopofldlnl
l'Ort"orm
(''''''......d
,_"
C1o<i<
of
Ito d;lfIl>y«l.
....
~
d«iti""
of
,h.
poop''''
'00"
po"".m
in,
"I'fOI'
.tC:
0«."
"""ruI.,.I,m.nl
"""<tel
of
,,;"""11..,
,"'
(,,,
""""oJ
''''0<1
"op
OOrtuoi
key'"
.~.".
"."."",
....,n,
....
roo.II'01
of
"ut
.nd
..
t> to p,o>id. i"" ...
\n<II"""""
0I"l
fr_
.....
U'".'iOll,AU....
by
j,.If.
"""'inl,..
"'1'
«1)
,""'"
doLI00rood
0,..."'0
"'"
.ASIC
CI'lI I
CPU
CPU
II
I
1bo iIIItru<llon In Ito .x,,,;
...(L•.•
dOOl
oulrol
.',II,,,tion
no'
"",f",",
a"",
cod.totho Cl'l: n ¥i.
I ,i>, ,he "
"'"
I'
of
10.
.ny
1"
1<
Rooo
..
.nih
....;"......""......
doddin,
INfr"
_1>1,
.Xt<1Itioll by
ond..",.,.
~''''''
f_
........~....
(Pun
D;,pby
P"",."OtI""'''''
Inpo'
buff"
Lomp~I.''''''''
n.r..,,,,
Elf
Of
".""0'
".."
C.",,,. ",.,in'
"'in"O\<o;Il<
-
iii""
of
CIo<k
,«1 fn'm Ill.
io
to
b<
i,"'f,
It
,h.
"ffor.
_,,"''''
"","'
"""'''(,.....
""""..011
"01'
RA!ot
<>rio_.
..
_,ed,
<>o>Iy
."""
00
lit.
..."'....
0,11<,""....
....
d
of..i1k
'"
<Ie"
...
po<
.ch
,«1)
<10<:14<0
,ho
",,_y
_h.,bI.
, 1
d.I.,
""d
Dd
papal
6&1>
U>d
inf",,,",·
(I'll
I
."'
....
"'>11'11<1'011
Cl'U
01"
",1<•.
Ito
it.
..
n'·
ox·
~
Ef;'
A<;'"""
For
JlUJIlill
(lnpu,
lIIaion
Ill;'
I/l,"u,tiv
"""fume
".rr..)
<Od.
,h
••
",t;rU,
.n~
LP\J
,
l~" •
0""'''","
.tt
(JiopIoy)~"
..
,.."ploI
of
,h,
....
fo,mlt'<>n
...
fd"J'Io~)
U>d
...
"
of
M.'Whmt
,
..
Pod,,,
~
f",od
."co".
Ih.
",.
of
I-(
.<ydot.
",.
-.-
-.-
I-(
otI'')'
....
~
_.'
---
_
._-
Computer, Ill. lo"",,''<>n
put
,hroo,.tJ
'0
,.,
d;'p1~
by
Ih.
,h.
t:1'\J U
'"
1"0<"""1. Upon
cvu
g
b.fo,"
koyboo,d
Ill.
'~-
<PO"
L
.•
-,
b,nol"
,,,
..
~-
.....
f.!
~-
-
'ode
(k<y
""J
<""
..
".d
bull",A,LI'lJ I
,h.
completion ol
,,,,'1,,, lho_
•
H
cOO,)
;n'o
f_""'
-
"
""'(lotl
,h,
""_"'1
'hi>
....
'
'-
-
f.!
'-
---
'"'0
in",,,,,,",n
tlllo
1011111<1100.
P'o<",inl,
-~,
...
M
-
~
•
--
-,
'h.
RAM
00>00
by
~
tlO,if!o,
In
,h,
CPU
I,
'hm
CPUUlII,.
CPUt,ond
dlOpI.~
chip
Il>b
iN"
~ot>J<I
..
CPU
I

3_
LSI SIGNAL DESCRIPTIONS
SC431n
Pin
N~
Si¥Iollllme
,
,
,
•
•
,
•
•
..
"
"
(CPU I)
".
n.
••
.'
.-"
Vr."
Vr~;
,
..
TEST!
fESTl
Il~SH
"".
In/Qu,
~,
~,
~,
,.,
"
'"
'"
'"
~,
0.,.,;,,1"
(h,p
~n.bl,
''f',,1
iIlA~J
",1«.
"V"I)
elli,
f.,bl,
.ipIoI ,RAM J
(h,p
Eo"'I.
,...,.1
(RAMI..1«,
ChIp
[.",1.
,ipal
._,
L"",n3~'''"'Y'
0..
......
1<1';'1_
Sol",« ><>lUI'
a"",
clo<k
Co""",,,d
All
11;<
........
1'1",,,,011,'
IlAM
During
I'r
Dot.
......
hilh
d"pol.y' HI",
'
k.y,....","'""",,,,,,n,.,ay t>
iDi,pol,y eIl,p 1
Low
I",,,,
i-
"
1
puI><
"3001, 1
l!l
G~D
".h
"pIIt
bu'
'''''''
11.0<1/'11.'",.
~
..
.>.>"
..
"",,1,
WIl
.....fb."",,\
S~kH'1
1<>.,
~h<:n
>ian-ol
, ,,,,,.1)
"Inol)
,,1«,
t,,;g,
,he
"pl';'
/
All
II.""
Io~_
'UOl
'01
,nr"'
-_..
S.'i'~
;,
.------_
bulf"
;>«_d,
...
..
,11<1
_---
,,,,,,for buff.,
"
"
"
'"
"
..
"
W
"
"
"
"
'"
'"
..
"
,",
1)101
~,
om
~.
."
~.
".
M.
".
."
."
C"D
".
,
'"
In/o.,
1",00'
1010.'
In/O'"
~
~,
0
..
~,
,.
~,
,,,
~,
'"
~,
~,
~,
ll.,.
Ilu>
(fo,
.d~,,,,
1ll,f'bY Chip I)
Ourl", di,ploy' Uilll
Du,I
..
,..~-irI
Add..,.
,n~
Di>pl., OIip I),
D",',..
dill""
Du,I"II
".d,ln
Sou'e< rol
l!tJsy
"lI",1
lJu,inc dnpl.,_
Du<i"~
,
Key
S,,<>be
""
S"o"," llgnal,
Ilu>
If."
..I"I(}V)
10
..
d I",
"",.1,
~.
,O<lt",
('I'IJ D
w...
,",
~....,."""
of
•
d..ogn,,,on
,Il,p.
don"l..",.tlonInll'lJ
..
momo"'.,~y
RA,'>I
Add",.
RMoI
Md'.., ''i'I,1
"50"
,h.
'.po,
buff...-
,00
\t\.\.\.\.\.
of
,II<
mp."
bolff...-
,nrl ,,,,,,for
..
JnITII'JllIllII
I)
h,g,
".",f"
buff",.RAM
buff...-InIIAM
Mom.nlOry
,nd
rro<"'''>r\
"