RCA 301 Programmer's Reference Manual page 40

THE CONSOLE
Register Display
When the computer is not running, no register is displayed. To display a register, it must be selected. To change
the contents of a register, it must be selected and then the proper bits (buttons) depressed. These buttons which
display the contents of a selected register are the rightmost bank in Figure 6 illustrating the layout of the buttons on
the console.
REGISTER SELECTION
Depressing one of the select buttons will cause the display of a register. The registers that can be selected are:
P, A, B, S, T, U, V — four characters in length.
NOR/N, SOR/M, FOR/L — two characters displayed; one is the operation code, the other the N Register
MR — Memory Register — two characters.
D — D Register — two characters.
SPECIAL PURPOSE SWITCHES
These are alternate action switches.
1. OCSP—(One Cycle Stop)
This switch permits "one status level at a time" operation by stopping the computer at the end of every
status level.
2. ICSP — (Instruction Complete Stop)
Permits "one instruction at a time" operation by stopping the computer prior to the staticizing of the
next instruction.
3. FPLS — (First Processing Level Stop)
Stops the computer after staticizing an instruction.
4. RDM — (Read Memory)
Allows the displaying of any diad in HSM.
5. WRM — (Write Memory)
Allows the placing of a diad into two locations in HSM.
6. HSMI — (HSM Inhibit)
Inhibits information from going to or coming from HSM.
7. BAI — (Bus Adder Inhibit)
Adding or subtracting ability of the Bus Adder is inhibited. Output of the Bus Adder is the same as
the input.
8. STLR — (Status Level Repeat)
Inhibits changing the current status level.
9. ISIM—(Inhibit Simultaneity)
Causes all instructions to be executed serially although they take place in the mode desired.
10. BCT — (Bypass Card Translation)
Bypasses the automatic card translation in the card read instruction. Two characters for each column
read will be placed in HSM.
11. INT — (Interrupt)
This button can be sensed by the CTC instruction when N = &.
12. WTAB — (Write to Table)
When set, this switch allows the arithmetic tables (HSM locations 0000-0199) to be written into HSM.
When reset, any attempt to write to the tables will cause an alarm.
13. SMDI — (Simultaneous Mode Inhibit)
When set, causes all Simultaneous Instructions to be performed in the Normal Mode. It also will store
the A Register to STA when the S Register is indicated in the Store Register instruction. If an EF/ED
is read, the Normal EF/ED indicator will be set.
14. ALI— (Alarm Inhibit)
When this switch is depressed the Computer will not stop on any error condition. The alarm indicator,
however, will light.
111-10
or its corresponding registers in the other modes.