Radio Shack TRS-80 26-3650 User manual

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TRS-80
PC-4 Pocket Computer and Cassette Interface
Catalog Number
TP9^
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CUSTOM MANUFACTURED FOR RADIO SHACK, ADIVISION OF TANDY CORPORATION

1. SPECIFICATIONS
Keyboard Iayout
SHd] S
GOSUB FOR TO STEP NEXT GOTO IF THEN PRINT '
LIST
ON INS
AC @HLTD
P4 P5 P6 ^
mcniziE]
pi P2 P3
mEram
Oa^*-TZ. IXon t
ETUrNSTOP END DEFM RUN UST INPUT ....._, *_ rJL- r^n r-Ln|—
—
ao—2IB M
Display
Display tube: AC- 61255
Display method: 5x7 dot matrix liquid crystal
Display capacity: 11 columns (alphanumeric characters and symbols)
Fundamental calculation
functions:
Built-in functions:
Commands:
Program functions:
Calculation range:
Program system:
Negative numbers, exponentials, parenthetical addition, subtraction,
multiplication and division (with priority sequence judgement
function (true algebraic logic)
Trigonometric/inverse trigonometric functions (angular units-degree/
radian/gradient), logarithmic/exponential functions, square root,
powers, conversion to integer, deletion of integer portion, absolute
value, symbolization, designation of number of effective positions,
designation of number of decimal positions, random numbers, n
INPUT, PRINT, GOTO, FOR-NEXT, IF-THEN, GOSUB, RETURN,
STOP, END, RUN, LIST, LIST A, MODE, SET, VAC, CLEAR,
CLEAR A, DEFM, SAVE, SAVE A, LOAD, LOAD A, PUT, GET,
VER
KEY,CSR, LEN, MID,VAL
±1 X1CT9to ±9.999999999 X10" and
(internal calculation uses 12 mantissa positions)
Stored system

Program language:
Number of steps:
Program capacity:
Number of memories:
Number of stacks:
Power supply:
Power consumption:
Battery life:
Auto power-off:
Dimensions:
Weight:
BASIC
Maximum 544 steps (maximum 1,568 steps when optional RAM pack
is loaded)
Maximum 10 programs (P0 through P9)
Standard 26, expandable to 94 (maximum 222 memories when optional
RAM pack is loaded) and exclusive character variable ($)
Subroutine —8levels
FOR-NEXT loop -4levels
Numerical value —6levels
Calculation elements —12 levels
Two lithium batteries (CR2032)
Maximum 0.02W
Main frame only -approximately 360 hours (continuous use)
Power is turned off automatically approximately 7minutes after
last operation.
9.8mmH X165mmWX71mm D(3/8"H X6-1/2"W X2-3/4" D)
116g (4.1 oz) including batteries
-2-

2. BLOCK DIAGRAM
LCD
AC-61225
Z\ R1-R15
V
CPU
HD61913A01
7y
v
D1-D8
CE1
CE2
OP
K1-K12
KEYBOARD
^> RAMI
HD61914
77
———.,
RAM2
HD61914
EXPANSION RAM MODULE
LCD: 12-digit dot -matrix display. Acharacter or anumber is displayed in
5X7 dots.
CPU: CMOS VLSI one-chip microprocessor unit.
RAM: Stores data and program. Each RAM has 1Kbytes (8K bits) capacity
and contains self-control circuit.
-3-

3. CPU (Central Processing Unit) HD61913
3-1 .Features
oCMOS one-chip CPU
oBuilt-in ROM: 100864 bits
oBuilt-in RAM: 1896 bits
oBuilt-in display driver
oMemory backup function
oClock: 400 kHz
Internal machine cycle: 200 kHz
Minimum instruction execute time: 10/xS
3-2. CPU Block Diagram
Control signals
A
ROM
(System
Program)
7\
Instruction
Decoder
Address
Control
V
Keyboard Signals
-4-

3-3. CPU Signal Descriptions
Pin No. Signal Name In/Out Function
1~4 D1 -D8 In/Out Data bus. Also designates RAM address while
signal OP is HIGH.
5INT Not used.
6~ 18 KI2- K1 In/Out Key input/output signals.
19 SW In Power switch input signal.
20-24 V5- V1 In LCD drive voltages. These voltages are
generated by connecting external resistors to
VDD2.
25, 26 OSO, OSI In/Out By connecting 56 kohm external resistance
between these terminals, clock pulse is inter-
nally generated.
27-72 R15- R7 Out LCD display signals.
73 GND In (zero) volt power source.
74, 75 CE1, CE2 Out Chip enable signals. CE1 selects RAMI at
HIGH level while CE2 designates RAM 2at
HIGH level.
76 VDD1 In —5.5V input.
77 VDD2 Out —5.5V output from the LSI.
Stays -5.5V at power ON. Goes to 0V at
power-off) or APO (Auto Power-Off).
78, 79 01, 02 Out Clock pulses.
80 OP Out When the signal is HIGH, the data bus becomes
address bus for RAMs and also becomes the
command code for the optional cassette tape
interface.
-5-

4. RAM (Random Access Memory)
HD61914 is 1Kbyte RAM and contains self-control circuits.
The following shows amemory map of RAM 1and RAM 2(optional RAM pack)
RAMI
System Memory
User's Area
RAM 2
000
21F
220
User's Area
7FF
800
FFF
Note: The above addresses are for when one word is 4bits.
_6-

5. SERVICING
5-1. Disassembly
Remove two screws from the back.
Lift and slide down the lower case.
Remove the battery cover.
Extract batteries.
Remove eight screws from the guide plate.
Remove the guide plate.
-7-

5-2. Trouble shooting
Note: Numbers in CAUSE column denote order of possibility.
A. Display
LSI's to function :CPU, RAMI
OPERATION
Turn the power switch on.
Push the ALL RESET
button on the back of the
computer.
TROUBLE
Dot display cannot be shown.
No display at all or unusual indication.
Some dots cannot be displayed.
RUNDEG
••
•>•••
•••.:
I"- i::,'
CAUSE
1. RAMI
2. CPU
CPU
1. CPU
2. LCD
3. Heat seal
B. Key Entry
LSI's to function:
CPU Key input operation, Displaying.
RAM 1Storing entered numbers or characters.
TROUBLE
No entry at al
Cursor moves, but entered number or character
cannot be displayed.
Only characters can be entered
CAUSE
t. CPU
2. Wiring between CPU and keyboard.
1. RAMI
2. CPU
3. Wiring between CPU and RAM 1
.
1. CPU
2. Wiring between CPU and keyboard.
-8

C. RAMI
(1
)
Remove optional RAM module if equipped.
(2) Push the ALL RESET button on the bottom.
(3) Operate DEFM 62 [EXE.
(4) Write the following program.
10 FOR I=1TO 87
20 A(I) =I
30 PRINT A(I)
40 NEXT I
50 PRINT "RAM OK"
60 END
(5) After writing the above program, confirm that the remaining program step is 0.
(6) Execute the program and confirm the display counts up from 1to 87 and shows RAM
OK by every depression of the [eTxeTJ key.
If the above operations cannot be made, RAM 1may be faulty.
D. RAM2(Optional RAM module)
(1) Install the RAM module in aPC-4.
(2) Push the ALL RESET button on the bottom.
(3) Operate [MODE 11and confirm that the remaining program step is 1568.
If the display shows the remaining step as 544 .
(a) RAM2is not functioning.
(b) Wiring between CPU and RAM 2has failed.
(4) Operate DEFM 190 |EXE| and confirm the display ***VAR:216.
(5) Write the following program.
10 FOR I=1TO 215
20 A(I) =I
30 PRINT A(I)
40 NEXT I
50 PRINT "MODULE OK"
(6) Execute the program and confirm the display counts up from 1to 215 and shows
MODULE OK by every depression of [EXEjkey.
If the above program is not performed, the RAM2(optional RAM module) may be at fault.
-9-

E. Discrimination Between CPU and RAM 1
If atest unit passes the preceding checking procedures and aproblem still exists,
follow the calculations.
(1) Manual Calculations Below
Perform the following calculations manually.
1+2X(3+4X(5+6X(7 +8)))
Correct answer 767
.
(In DEG mode)
(TAN (COS (SIN (LOG 100) ))) [EXE
Correct answer 0.0174550616
If the above calculations cannot be made, the CPU may be faulty.
(2) Program
Execute the following program after pushing the ALL RESET button on the bottom.
10 FOR I=1TO 2:FOR J=1TO 2:FOR K=1TO 2:
FOR L=1TO 2
20 NEXT L:NEXT K:NEXT J:NEXT I
30 GOSUB 40 :PRINT "END" :END
40 GOSUB 50 :
50 GOSUB 60 :
60 GOSUB 70 :
70 GOSUB 80 :
80 GOSUB 90 :
90 GOSUB 100
100 GOSUB 110
110 RETURN
RETURN
RETURN
RETURN
RETURN
RETURN
:RETURN
:RETURN
After execution of this program,
display should show END.
If the above manual calculations (1 )are done but the program (2) cannot be executed,
RAMI may be faulty.
-10-

5-3. Test Program
Program
No.
Line
No. Program
PO 10 VAC
20 FOR 1=1 TO 2:FOR J=2 TO 3:FOR K-3TO4: FOR
L=6TO 4STEP -1
30 NEXT L:NEXT K:NEXT J:NEXT 1
40 GOSUB 50: PRINT 'TEST 1OK" :END
50 GOSUB 60: RETURN
60 GOSUB 70 :RETURN
70 GOSUB 80 :RETURN
80 GOSUB 90 :RETURN
90 GOSUB #1 :RETURN
P1 10 IF "AB" ="AB" THEN 20
15 GOTO 1
20 IF "A"<"AB" THEN 30
25 GOTO 1
30 IF "AB">"A" THEN 40
35 GOTO 1
40 IF "12" £"AB" ;IF "AB" >"12" THEN 50
45 GOTO 1
50 IF -123* 123; IF 123 <-123 THEN 1
60 IF -1234 >-123 THEN 1
70 IF -123 :£ -1234 THEN 1
80 IF 123 >456 THEN 1
90 IF 456= 123 THEN 1
100 GOSUB #2 :RETURN
P2
Hotel
10 IF RND (SIN 195+ COS 234+TAN 1e-3+ EXP 1+LOG 163,
-5) #4.0839 THEN 1
20 C=C+12345*12345/234/345+SQR 0+SQR 2+SO.R-30+ SIN 30t 2
30 FOR H--5 TO 4:D=D+ RND (5544.4455, H): NEXT H
40 A-1 :E=A (A (A (A (A (A (A)) I)))
50 GOSUB #3
60 RETURN
P3 Hon 210 X-123 :0$="H&J" :$-0$+"="
20 $= MID (1 ,3) +MID (4) +"ABC"
30 GOTO #4
P4 10 IF l+J+K+L*15 THEN 1
20 IF A+B+ E+ X- 125 THEN 30
25 GOTO ER
30 IF $*"H&J =ABC" THEN 1
40 IF RND (C, -5)* 1894.4034 THEN 1
50 IF RND (D, 2)* 55000 THEN 1
60 GOTO #5
P5 10 GOTO 20
15 RETURN
20 GOTO 15
P9 10 FOR A= 1TO 201 :A(A) =A+9999999000: NEXT A
20 $= "ABCDEFGHIJKLMNOPQRSTUVWXYZ* +/-"
30 FOR A=1 TO 201: IF A(A) *9999999000+ A THEN ER
40 NEXT A: IF $*"ABCDEFGHIJKLMNOPQRSTUVWXYZ* +/-"
THEN ER
50 |PRINT 'TEST OK! "
nnot bbfully entered if you use aone-key command (e.g.
ne 10 ca SHIFT J
IF). Therefore, enter the program manually without spaces.
2. P3 line 10; "&" can be entered by . .
.
(a) MODE f-T] (EXT mode set) (b) press the [SHIFT] (the red S) key
(c) Press tne "U" key (d) IMODEI rr] (EXT mode reset)
II -

Testing Procedure
Save the test program on acassette tape through acassette tape interface unit by the
operation SAVE A|EXE
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
Install aRAM module into the test unit (PC- 4).
Push the ALL RESET button on the bottom of the test unit.
Connect the PC -4to acassette tape interface and atape
recorder which contains atest program cassette tape.
Load the test program from the cassette tape by the operation LOAD AEXE
After loading the Program change the PC- 4to WRITE mode by the operation
MODE 1and confirm that the remaining program step is 789.
Operate [MODE] O(RUN mode selection).
Execute PO (Program numberO).
Confirm the display "TEST 1OK".
Clear the programs POto P5.
Example to clear P2 .. .
(a) SHIFT 2(P2 designation)
(b) MODE 1(WRITE mode selection).
(c) CLEAR jEXEj (erasing P2)
Note: SHIFT is the red Sbutton.
Change the PC-4 to RUN mode by [MODE! [EXEJ.
Operate DEFM 176 |EXE
Execute P9.
Confirm the display "TEST OK!
-12-

6. PROGRAM COMMAND LIST
Classification Command
Name Format Function
Input
statement
INPUT INPUT variable string Causes data to be entered from the key-
board during execution of aprogram.
The program execution is stopped until
after the end of input.
KEY Character variable =KEY Reads acharacter entered during execu-
tion of aprogram and assigns it to a
character variable.
Since the program is not stopped by this
command, nothing is assigned to the
character variable if no key entry is made.
Output
statement
PRINT PRINT output control
function J'I
output element J'I...
Outputs the designated output element.
CSR CSR n<j ;l(O^n <^^) Displays from the designated nth
position.
Branching GOTO GOTO I""6™)
Invariable 1
Causes control to jump to the designated
line number.
IF...
TTHENl
IF comparison expression
TthEN line no. 1
\;command/
Causes control to jump to the line
number following THEN, or executes
the command following ";", if the
result of the comparison is true.
Causes control to proceed to the next
line number if the result of the com-
parison is false.
GOSUB GOSUB (iinen°\
[variable!
Calls out the subroutine of the desig-
nated line number for execution. After
the subroutine is executed, control
returns to the GOSUB statement by the
RETURN statement to proceed to the
command following that statement.
RETURN RETURN Signifies the end of asubroutine;
returns control to the command/statement/
function next to the GOSUB statement.
Looping FOR FORv =e1TOe2[STEPe3]
*v denotes anumerical
variable, and el, e2 and e3
represent anumerical ex-
pression respectively.
Declares the beginning of aloop in
which numerical value vchanges from
initial value el to terminal value e2 in
increments of e3. The loop is repeated
"e2-e1 ,."
_+1 times
ej
between the FOR and NEXT statements.
If the increment e3 is omitted, e3 is
regarded as "1".
NEXT NEXT vSignifies the end of aFOR loop.
If the result of vplus e3 is equal to or
smaller than e2, the loop is repeated
again. If it is greater than e2, control
proceeds to the line next to the NEXT
statement.
-13-

Execution stop STOP —
STOP Stops the execution of aprogram tem-
porarily to bring the system into akey-
in wait state. The execution can be
continued by pressing the |EXE |key.
Execution end END END Signifies the end of aprogram; the
system returns to its pre-execution
state. The execution of aprogram, once
ended, cannot be continued even if the
[EXEJ key is pressed.
Data clearing VAC VAC Clears all variable data for aprogram.
Program listing LIST LIST [line no.] Displays alisting of all the statements in
aprogram from the designated line
number downward.
All program
listing
LIST ALIST ADisplays alisting of the statements in all
programs.
Program
execution
RUN RUN [line no.] Causes aprogram to start from the
designated line number.
Program
erasing
CLEAR CLEAR Clears the currently designated program
area of aprogram.
CLEAR ACLEAR AClears all the programs.
Angular unit
designation
MODE MODE <> 5^>
Designates trigonometric angular units as
degree (4), radian (5) or gradient (6).
Format
designation
SET fEn|
SET<^ Fn \
[ti J(0^n^9)
Designates the number of effective
positions or number of decimal positions
for the displayed numerical value.
Character
function
LEN LEN (character variable) Calculates the size of the character
variable.
MID MID <m [,n]) Extracts ncharacters from the mth
character in the exclusive character
variable (S).
VAL VAL (character variable) Converts the numbers in acharacter
variable to anumerical value.
Option use SAVE SAVE ["filename"] Records only the program in the
currently designated program area on
tape.
LOAD
SAVE A
LOAD ["filename"]
SAVE A["filename"]
Calls out the program from the tape and
loads it to the currently designated
program area.
Records the programs in all program
areas on tape at the same time.
LOAD ALOAD A["filename"] Calls out all programs from the tape and
loads them to the respective program
areas.
PUT PUT ["filename"]
variable
Records the data in the variable on tape.
GET GET ["filename"] variable Calls out the data from the tape and
loads it in the variable.
VER VER ["filename"] Checks to confirm that the programs
or data have been recorded on the tape
properly.
-14-

7. ERROR MESSAGE LIST
Error Code Meaning Cause Corrective Measure
1Memory overflow or
system stack overflow
•Program cannot be written due to
insufficient number of steps or
memory cannot be expanded.
•Stack overflow due to acomplicated
calculation formula.
•Clear unnecessary programs or
reduce the number of memories.
•Divide and simplify the numeri-
cal expression.
2Syntax error •Amistake has been made in writing
the program, etc.
•The left side format is different from
the right side format in asubstitution
statement, etc.
•Correct the error in the input
program, etc.
3Mathematical error •The calculation result of anumerical
expression is 10100 or greater.
•Outside the input range of anumerical
function.
•The result is indefinite or impossible.
•Correct the calculation formula
or data.
•Verify the data.
4Undefined line
number error
•No designated line number for a
GOTO statement or aGOSUB
statement.
•Correct the designated line
number.
5Argument error •For acommand or function that
requires an argument, the argument is
outside the input range.
•Correct the argument error.
6Variable error •Attempt was made to use amemory
which has not been expanded.
•Attempt was made to use the same
memory for anumerical variable and
acharacter variable at the same time.
•Expand the memory properly.
•Do not use the same memory
for anumerical variable and a
character variable at the same
time.
7Nesting error •ARETURN statement appears other
than during subroutine execution.
•ANEXT statement appears other than
during aFOR loop or the variable of
the NEXT statement is different from
that of the FOR statement.
•Subroutine nesting exceeds 8levels.
•FOR loop nesting exceeds 4levels.
•Remove the unnecessary
RETURN statement or NEXT
statement.
•Reduce the subroutines or
FOR-NEXT loops to within
the maximum levels.
9Option error •Execution is performed in the PRT
mode, or an option command such as
SAVE is executed when no printer or
tape recorder is connected.
•Connect aprinter or tape
recorder.
Release the PRT mode.
-15-

II. CASSETTE INTERFACE (26-3651)
SPECIFICATIONS
Output terminal:
Input terminal:
Remote control terminal:
Data recording format:
Power source:
Power consumption:
Battery life
(for continuous operation):
Dimensions:
White mini-plug, output impedance: approx. 40 kohms,
output level: 3~50mV
Black mini-plug, input impedance: approx. 20 kohms,
input level: 2.5 ~50V.
Gray sub mini-plug, 24V, 1Aor less.
Kansas City standards (300BPS).
(For remote control) Two AA size dry batteries.
0.3W.
Approx. 7hours.
173mmW X114mmD X31.5mmH.
2. BLOCK DIAGRAM
D4
6VODS^
Q.
£CE2
s
CO
c
Q
E
oOP
GND
=0
=c>
LSI
HD43110
77
CRYSTAL
OSCILLATOR
FILTER
CIRCUIT
SHAPING
CIRCUIT
REMOTE
CONTROL
CIRCUIT
DMIC
EAR
REMOTE
£>
3
CO
H
a>
30
CD
8
Q.
CD
LSI :Kansas City standards applied cassette tape
interface LSI.
Transfers serial data by the following frequencies.
Data"1" 2,340 Hz
Data"0" 1,170 Hz
Filter Circuit: Converts LSI's data pulse into AC
waveform for tape recorder.
Shaping Circuit: Converts AC waveform data from tape
recorder into square pulse for the LSI.
-16-

3. LSI (HD43110)
HD431 10 is acassette tape interface LSI with Kansas City standards which transfers data between
the CPU and cassette tape recorder.
Data "0" and "1" are transferred in serial as 1,170 Hz and 2,340 Hz frequency pulse respectively.
Data is transferred at 300 bits per second.
The following lists the functions of each terminal of the LSI.
Pin No. Signal Name In/Out Function
2OSC In Clock pulse (32,768Hz) input.
7VDD' Out -3V output.
8CONT In The LSI functions only when
the terminal is HIGH.
9VDD1 In -3V input.
10 CE In Chip enable terminal. The LSI
is designated from PC- 4when
the terminal is HIGH.
11 SP In Strobe pulse input from PC-4.
13 D4 In/Out Serial data input/output.
14 GND In 0V input terminal.
17 C3 In Data input from cassette tape.
18 C2 Out Data output to cassette tape.
19 C1 Out Remote control (auto stop)
signal output.
-17 -

4. CIRCUMFERENCE CIRCUITS
4-1. Clock Pulse Generator
32,768 Hz signal is generated by the crystal oscillator and is shaped by the inverters.
D^®.©
'•—*y-
^Dr-
7>7
4-2. Remote Control Circuit
wv—wv*
—
1
Q1
4T 6
-3V
RY
ON OFF
Q2 REMOTE
When signal C1 is HIGH, transistors Q1 and Q2 turn on causing relay RY to be
switched on so that the REMOTE terminal becomes active.
4-3. Shaping Circuit and Filter
©®
)MIC
)EAR
-18-

Filter waveforms
approx. I
~*l 1.2 kHz r* |< sj approx. 2.4 kHz
-3V
@-3V
©-3V
Data output C2 from the LSI is integrated (waveform (§) )and shaped into an AC
waveform (waveform ©)by capacitor dand resistor r1.
©
®
<B>
Input signal from tape recorder ®is integrated by capacitor c2 and resistors r2
and r3 (waveform (|)).
The waveform (§) is cramped between —3V and OV by diodes d1 and d2.
-19-