SCELBI Front Panel Basics

STATUS LED MEANINGS

INT INTERRUPTED (CPU IN STATE T1I)
RUN RUNNING (CPU IN STATE T1)
STOP CPU IN STOPPED STATE
LEFT RIGHT STATUS
OFF OFF READ 1st BYTE OF INSTRUCTION
ON OFF MEMORY READ (INSTRUCTION OR DATA)
OFF ON I/O OPERATION
ON ON MEMORY WRITE

JAM SINGLE BYTE INSTRUCTION

  1. Set instruction code into switches B0-B7
  2. Push INTERRUPT switch
  3. Step until interrupt LED goes on
  4. Step until interrupt LED goes out

JAM TWO BYTE INSTRUCTION

  1. Set instruction code into switches B0-B7
  2. Push INTERRUPT switch
  3. Step until interrupt LED and left STATUS LED both go on
  4. Set data code into switches B0-B7
  5. Step again

JAM THREE BYTE INSTRUCTION

  1. Follow two byte procedure
  2. Set second data code into switches B0-B7
  3. Step again

TO LOAD A MEMORY LOCATION WITH DATA

  1. Load H with target high address (jam 056 HHH)
  2. Load L with target low address (jam 066 LLL)
  3. Load memory, immediate (jam 076 DDD)
  4. Increment L (jam 060)
  5. Repeat steps 3 and 4, as needed

TO DUMP MEMORY

  1. Load H with target high address (jam 056 HHH)
  2. Load L with target low address (jam 066 LLL)
  3. Load LAM (jam 307) - overwrites A register
  4. Increment L (jam 060)
  5. Repeat steps 3 and 4, as needed