View source for KY11-A Programmer's Console

[[Image:pdp1120a.jpg|200px|lright|thumb|Front panel mounted]]

The '''KY11-A Programmer's Console''' is the [[front panel]] for the [[KA11 CPU]] used in the [[PDP-11/20]] and [[PDP-11/15]].

It allows a programmer to display and deposit data in [[main memory]], and start, [[halt]] and [[single-step]] the [[Central Processing Unit|CPU]]; it also displays substantial amount of information as the machine operates.

It consists of a [[DEC card form factor|hex]]-wide [[printed circuit board|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); the whole plugs into the CPU's [[backplane]]. There is also a printed plastic inlay, and a metal bezel which holds the inlay in position, and bolts to the [[BA11-C Mounting Box]] which holds the CPU. 

==Displays and controls==

[[Image:PDP-11-20FrontPanel.jpg|400px|left|thumb|Front pane details]]

The 'Address' and 'Data' indicator arrays display memory [[address]]es and data.

The 'Fetch', 'Exec' (Execute), 'Source', and 'Destination' indicators on the right hand side indicate that the CPU's [[state machine]] is in that [[KA11 CPU#State machine|major state]]. In the Source and Destination major states, the two 'Address' lights will count up, depending on the [[PDP-11 architecture#Addressing modes|addressing mode]] of that operand. The 'Run' light indicates that the CPU is [[execute|executing]] [[instruction]]s; the 'Bus' light indicates that a [[peripheral]] is in control of the [[UNIBUS]], either for an [[interrupt]], or performing [[Direct Memory Access|DMA]].

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 either a single instruction, or single bus cycle, depending on the position of the 'S-Inst/S-Cycle' switch.
 
{{PDP-11}}

[[Category: PDP-11s]]