KY11-D Programmer's Console
The KY11-D Programmer's Console is the front panel for the KD11-A CPU used in the PDP-11/35 and PDP-11/40. It allows a programmer to display and deposit data in main memory, and start, halt and single-step the CPU.
It consists of a large board containing lights and switches, to which is attached a light shield (a flat plate with holes drilled through it, which prevents light from one light from straying into neighbouring light positions). It is connected to the CPU by a number of flat cables which plug into Berg headers on the console's board, and on boards of the CPU. There is also a printed plastic inlay, and a metal bezel which holds the inlay in position, and bolts to the BA11-F Mounting Box (also BA11-D and BA11-K) which holds the CPU.
Displays and controls
The 'switch register' is used to enter both addresses and data. The 'Load Addr' (Address), 'Exam' (Examine), 'Start', and 'Dep' (Deposit) switches perform the named function. If the CPU is halted, toggling the 'Continue' switch does a variety of things, depending on the position the 'Enable/Halt' switch is in. In the Enable position, the CPU continues operating; in the Halt position, it performs a single instruction.
Most front panel operations are implemented by microcode in the CPU. (See Section 3.2.1, "KY11-D Programmer's Console" in the KD11-A processor manual, below, for details.) Therefore, the CPU must be basically fully functional for the front panel to work.