CENTRAL PROCESSOR

GENERAL DESCRIPTION The console indicating and control panel (usually termed the control console) is mounted on the side of the f i r s t rack. Below the panel is the console desk The central p r o c e s s o r (Figure IV-1) p e r f o r m s the and above i t is the half -length door covering a main- computational (arithmetic), the storage, and the con- tenance control panel. Inside of the f i r s t rack a r e the t r o l functions f o r the GE-225 System. The p r o c e s s o r main power supply f o r the p r o c e s s o r , the power

is

housed in three equipment r a c k s which a r e bolted distribution panel, and the electronic control logic together. f o r the c a r d reader, c a r d punch, paper tape r e a d e r ,

and paper tape punch.

Figure IV-1. The Central P r o c e s s o r

The second rack contains the majority of the elec- tronic counters, registers, timing circuits, and control logic associated with the processor.

The third rack contains the remaining registers, the magnetic core memory and i t s associated timing and control logic, and the logic for the controller selector.

Cable Connections

All peripherals a r e connected to the central proces- s o r by cables. The typewriter is connected directly by cable to the f i r s t rack of the central processor.

The card reader is also connected to the f i r s t rack, but through a junction box mounted in the r e a r of the

console desk.

The peripheral equipments which have controllers a r e connected to the controller selector by cables s o that each peripheral controller is connected in paral- lel with the controller selector and in s e r i e s with every other controller. Cables a r e connected to two plugs in the third rack of the central processor. The output cable from the central processor is connected to one plug, and leads to the input plug of the first controller. Controllers a r e connected to each other by cables which lead from the output of one to the

H A S R 5 )S68 DC

381 CHO 7 0 4 DS7

input of the next. The output of the last controller leads back to the controller selector, and connects to the second of the two plugs in the third rack of the central processor.

The card punch is connected to the central processor through a plug located on the same connector panel on the third rack a s the two plugs for the controller selector. The punch cable is clamped in place by means of a 'shoe' connector attached to the end of the cable.

Controls and Indicators

The GE-225 System operator constantly watches and uses the controls and indicators of the central proces-

sor. Most of the control switches and indicator

-

lights a r e on the control console which provides switches for manual control, indicates the status of equipment, and displays the contents of certain reg- isters. In ,addition to the control console, there is a maintenance panel which has three a r e a s of interest and use to the operator.

A. MAINTENANCE

PANEL.

The maintenance panel of the central processor, illustrated in Figure IV-2, is located inside the door which is above the control console. It is usedmostly by service

CLE 1534 DC

Figure IV-2. The Maintenance Panel of the Central Processor

engineers, but t h e r e a r e two i t e m s of concern

PARITY Alarm. If the STOP ON PARITY ALARM switch is engaged when a p a r i t y e r r o r is detec-

tempt to select a controller through the con- t r o l l e r selector for an input/output operation.

The ECHO a l a r m light can be turned off only by depressing the RESET ALARM switch. The

a l a r m indicates the following conditions:

1. The selected controller is busy (delay not programmed).

2. An erroneous address was program- med, the addressedplug is not installed.

P 5 4 3 2 1 5 6 7 8 9 10 1 1 12 13 14 15 16 17 18 19

I ^{00 000} 000 000 000 000 000

0 I 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 18 19

A 00 000 000 000 000 000 000

0 I 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 18 19

R E S E T A

iz-[pJ[-q[

A L A R M

-

-

-

-

M A N U A L

E

DECIMAL M O D E

- -

-

Figure IV-3. The Control Console

- -

-

-

-

L

C A R D PUNCH R E A D Y

- -

E C H O A L A R M

-

B K O N L Y

-

-

-I --- -C A R D

R E A D E R READY

1

-

C A R D READER

E:k:

^{PUNCH C L R Q}

1

--

_-

-

N REGISTER

READY

AIM

3. Controller is off line.

4. Power is off to controller.

5. Controller is malfunctioning.

CARD READER Alarm. This a l a r m is turned punch instruction is attempted, the ready light will go off and the CARD PUNCH andPRIORITY

the index groap that has been selected by the p r o g r a m (Groups 0 through 3 1). Each group h a s four r e g i s t e r s , 0 through 3. When a l l lights a r e off, group z e r o is available without special selection. Only index groclp z e r o is s t a n d a r d on the GE-225 System; additional octal representation. By reading these groups, the oilerator can know the location of the instruction switch in the downpositionprevents the P counter f r o m incrementing. When the operator r e t u r n s the SAVE P

Figure IV-4. Control Switches on the Control Console

STOP ON

PARITY ALARM

m i s t a k e by clearing the A r e g i s t e r with the R.3SE'I: A activated just before setting the AUTO/MANUAL switch to AUTO a t the beginning of p r o g r a m

START, In the automatic mode of operation, depressing the START pushbutton initiates act- ion. After the operation begins, the program r u n s automatically and despressing the START switch again has no effect. In the manual mode of operation, depressing the START switch causes the execution of one instruction o r one word time, depending upon the setting of the INST/WORD switch.

A 4 I (A to I). This switch i s effective only in the manual mode of operation. Depressing the A to I pushbutton t r a n s f e r s the contents of the A register, including the sign bit, to the I r e g i s t e r . The contents of the A r e g i s t e r r e - main unchanged, and can be cleared by tog- gling the RESET A switch. The A to I switch is used to manually load an instruction into the I r e g i s t e r o r to c o r r e c t an instruction already there.

XAQ. This switch is effective only in the man- r m o d e of operation. Depressing XAQ causes

an exchange of information between the A and Q r e g i s t e r s . That is, the contents of A go into Q and the contents of Q go into A. This permits the operator to observe the contents of the Q register. By using the RESET A switch and the option switches, the operator can clear and c o r r e c t the contents of the Q r e g i s t e r while saving the contents of the A register.

STOP ON PARITY ALARM/NORM, This is a two-position, rocker-type switch. It determines the response of the central p r o c e s s o r to the detection of

a

parity e r r o r . When the STOP ON PARITY ALARM portion of the switch is depressed, the central processor halts each time a parity e r r o r is detected and the PARITY and PRIORITY a l a r m lights come on. When the NORM (normal) portion of the switch is depres- sed, the central processor continues operation regardless of parity e r r o r s , and the only indi- cation of a parity e r r o r is the fact that the PARITY a l a r m light is turned on. The setting of the STOP ON PARITY ALARM/NORM switch is determined by the programmer. If he has included remedial action throughout the program to take c a r e of parity e r r o r s and to r e s e t the PARITY a l a r m light, he will specify the setting of the STOP ON PARITY ALARM/NORM switch to the NORM position. If he has not included remedial steps in the program, he will want the program to halt a t time of a parity e r r o r , s o will specify the setting of STOP ON PARITY ALARM,

Table I contains a summary of the controls and indi- c a t o r s of the maintenance panel and control console.

It is recommended that the student operator remove the table from the manual and keep

it

in a handy place a t the console for quick reference.

TABLE I.

FUNCTIONS OF CONTROLS AND INDICATORS O N CENTRAL PROCESSOR

r

Group

A l a r m Indicator Lights

Ready Indicator Lights

Control o r Indicator PRIORITY a l a r m light ( r e d )

PARITY a l a r m light ( r e d )

OVERFLOW a l a r m light ( r e d )

CARD PUNCH a l a r n l light ( r e d )

ECHO ALARM light ( r e d )

CARD READER a l a r m light ( r e d )

CARD PUNCH READY light (green)

Func t lon Indicates:

1. AUTO/MANUAL switch is in NlANUAL position.

2 , P a r i t y a l a r n l condition.

3 . C e n t r a l p r o c e s s o r does not have priority.

4. C a r d punch o r c a r d r e a d e r a l a r m condition.

Indicates:

1. Menlory -chec king c i r c u i t s of p r o c e s s o r detected p a r - ity e r r o r while p r o c e s s o r in autonlatic mode.

2 . P a r i t y e r r o r connected with tape r e a d e r .

3. Parl.ty e r r o r detected as data received f r o m a con- t r o l l e r through controller s e l e c t o r .

Indicates:

1. Capacity of the A r e g i s t e r was exceeded.

2. Illegal divide attempted.

3. Data shifted, l e f t o u t of the A r e g i s t e r .

Indicates c a r d punching was attempted when c a r d punch was not in a ready condition.

Indicates a n uilsuccessful atteixpt t o select a controller f o r ally of these reasons:

1. Controller busy 2 . I n c o r r e c t a d d r e s s 3. Controller off line 4. Power off to controller 5. Malfunctioning controller.

Indicates c a r d reading was

at-

ternpted while the c a r d r e a d e r was not ready (not s e t up, busy, misfeed, o r c a r d jam. )

Indicates when c a r d punch is In ' r e a d y ' status.

Group

Ready Indicator Lights (Cont. )

Register Display Lights and Switches

Control o r Indicator CARD READER READY light (green)

N REGISTER READY light (green)

AIM light (green)

8K ONLY Indicator (green)

DECIMAL NODE Indicator (green)

INDEX GROUP indicator lights

P counter display lights

SAVE P switch

I r e g i s t e r display lights A r e g i s t e r display lights

Option Switches

RESET A switch

Function

Indicates when c a r d r e a d e r is in 'ready'status.

Indicates N r e g i s t e r is ready t o receive input/output information and no illegal o r improperly programmed instruction h a s

been given to typewriter o r paper- tape reader/punch.

Indicates that optional automatic interrupt mode is operative.

Indicates, when lit, that 8, 192 nleniory locations a r e available.

Indicates, when lit, that the c e n t r a l p r o c e s s o r is in the dec inlal mode.

Indicates index group that h a s been selected.

Display location of instruction in I r e g i s t e r ( s e e text f o r ex- c ept ion).

P r e v e n t s P counter f r o m incrementing.

Display c u r r e n t instruction.

Display contents of the A r e g i s t e r .

Feed infornlation into the A r e g i s t e r while in e i t h e r manual o r automatic modes and r u n special routines such as GAP a s s e m b l i e s in the automatic mode.

C l e a r s contents of A r e g i s t e r to all z e r o s when manual switch is engaged.

Group Control Switches

LOAD CARD switch C a u s e s c a r d r e a d e r to execute

RESET P switch R e s e t s P counter to all z e r o s

AUTO/NlANUAL switch Selects ailtoillatic o r nlanual inode of operation of c e n t r a l

INSTR/WORD switch Selects leng-tll of cycle of

START switch Initiates execution of one cycle

of operation (instruction o r word);

in autoillat ic

.

irlitllttes execution

A '

I switch T r a n s f e r s contents of A r e g i s t e r to I r e g i s t e r (effective only when

Exchanges coiltents of A and Q

STOP ON PARITY ALARM/NORNl D e t e r m i n e s whether c e n t r a l Control o r Indicator

PWR ON switch

PWR O F F switch

RESET ALARM switch

Fuilc t ion

Applies DC power to the c e n t r a l p r o c e s s o r , and 400 card/minute r e a d e r .

T u r n s off DC power to the c e n - t r a l p r o c e s s o r , control console, and 400 card/minute r e a d e r . C l e a r s a l a r n l conditions (effec - tive only when MANUAL switch is engaged).

v

Function

Shows contents of N r e g i s t e r input o r output for the paper tape r e a d e r , paper tape punch, o r typewriter.

C l e a r s contents of N r e g i s t e r to zero.

Group Mainteilanc e Panel

Control o r Indicator N register indicators

CLEAR N switch

SETUP PROCEDURES

Setting up the c e n t r a l p r o c e s s o r f o r operation involves only bringing power up and setting control switches.

The s i x s t e p s listed below a r e designed to s a v e data

Loading an Instruction Manually

Any instructiori that is intelligible to the GE -225

3. Toggle the RESET A switch.

a. If a binary c a r d , u s e RCB, octal corresponding to the ones (the lights) of the A r e g i s t e r . These switches a r e now a

4. Raise the optioil switches corresponding to the ones of the new information to be e n t e r e d

Sequencing through Programs

I t is possible to manually sequence through a pro- If these p r o c e d u r e s fail the operator can follow the g r a m , s t e p by s t e p , and examine each instruction p r o c e d u r e s of the following section.

by reading the instruction r e g i s t e r . T h i s i s accom-

plished with the following steps. (Assume the INSTR Setting and Clearing Decimal Mode. Normally, the switch is engaged) : p r o g r a m will s e t and c l e a r the decimal mode. If f o r any reason the o p e r a t o r finds it n e c e s s a r y to do this manually, the following p r o c e d u r e s may be used. As 1- S e t the AUTO/MANUAL switch to MANUAL, previously mentioned, the DECIMAL MODE light on

the console will be on when the c e n t r a l p r o c e s s o r i s in the decimal mode.

2. Branch to the s t a r t i n g location of the p r o - g r a m to be examined:

a. S e t a BRU instruction into A r e g i s t e r , A. TO S E T THE DECIMAL MODE:

including the a d d r e s s of the f i r s t in-

struction to be executed (BRU is octal 1. Set the AUTO/'MtiNUt~L switch to MAN-

2600000). UAL.

b. D e p r e s s A to I switch. 2. Toggle the R E S E T ^LA. switch.

3. P r e s s START switch once f o r each in- struction to be executed; r e a d the I r e g i s t e r and P counter a f t e r each step.

3. P u t the Set Dec Mode instructiorl (octal 2506011) into the r e g i s t e r .

4. D e p r e s s the A to I switch.

Special Modes 5. D e p r e s s the START switch.

Normally the p r o g r a m will s e t and c l e a r out special modes, such as the decimal mode, index group s e l e c t ,

6. Check to be s u r e the DECIMAL MODE light came on.

and the automatic i n t e r r u p t mode (AIM). The oper-

a t o r will seldom need to s e t these conditions, but may ^B. TO C L E A R DECIMAL R / ~ O D E (SET BINARY occasionally have to c l e a r them manually. F o r in- MODE) :

s t a n c e , a p r o g r a m being debugged may b e aborted, and the s p e c i a l options a r e left on.

The p r o c e d u r e f o r clearing AIM, index group s e l e c t , and decimal mode a r e described in the following paragraphs. If these p r o c e d u r e s fail, m o r e elaborate p r o c e d u r e s a r e given in the sections immediatelyfol- lowing.

C l e a r i n g with PWR ON. A quick way to turn off the automatic i n t e r r u p t mode, c l e a r out index group s e l e c t , and change f r o m the decimal mode to binary is to u s e the PWR ON switch, following these s t e p s (assume power is on to c e n t r a l p r o c e s s o r ) :

1. Set the AUTO/MANUAL switch to MANUAL.

2. Set the INSTR/WORD switch to WORD.

3. D e p r e s s PWR ON switch.

4. Make visual checks to s e e i f goal is accom- plished.

1. Set the AUTO/MANUAL switch to MAN- UAL.

2. Toggle the RESET A switch.

3. P u t the Set Binmode instruction (octal 2506012) into the ^A r e g i s t e r .

4. D e p r e s s the A to I switch.

5. D e p r e s s the START switch.

6. Be s u r e the DECIMAL MODE light went off.

Automatic Interrupt Mode. The Automatic Interrupt Mode, which

is

p r e s e n t a s an optional f e a t u r e on s o m e GE-225 Systems, is usually t u r n e d on and off by p r o g r a m control. Occasionally, however,

it

may b e d e s i r e d to turn this mode of operation on o r off man- ually a s follows:

A. MANUAL AIM TURN-ON PROCEDURE

5. Set the INSTR/WORD switch to INSTR,

1. Set the AUTO/MANUAL switch to the MANUAL position.

At s t e p 4, note tha t the DECIMAL MODE light on the console will go out AIM light on control console will go out (if on), and index group lights will go out.

2. If the p r o g r a m is to b e r e s u m e d a t the point of manual interruption, d e p r e s s

the SAVE P switch to p r e s e r v e the con- tents of the P r e g i s t e r . Also, r e c o r d the contents of the A r e g i s t e r on the log sheet.

3. Introduce a S E T PST instruction (octal 2506015) into the computer through the control console using the technique des- 2506015) into the computer through the console switches using the technique d e s c r i b e d under

'

Loading an Instruc- tion Manually.'

4. After the S E T PST instruction has been s e t and executed, follow that command with a SET PBK instruction (octal 2506016) through the console switches.

5. Next, s e t a branch instruction with the

5. Load the STA instruction (0300000) into the A r e g i s t e r .

Im Dokument GE-200 Series Operating Manual (Seite 41-57)