Difference between revisions of "KDF11 CPUs"

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(Floating point: Link to FP11)
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There are several single-board CPUs which all use the 'Fonz' [[F-11 chipset]]:
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There are several single-board CPUs which all use the 'Fonz' [[F-11 chip set]]:
  
 
*[[KDF11-A CPU]] - M8186 - [[QBUS]] [[DEC card form factor|dual]]-width CPU used in the [[PDP-11/23]]
 
*[[KDF11-A CPU]] - M8186 - [[QBUS]] [[DEC card form factor|dual]]-width CPU used in the [[PDP-11/23]]
 
*[[KDF11-B CPU]] - M8189 - QBUS quad-width CPU used in the [[PDP-11/23_PLUS|PDP-11/23+]]
 
*[[KDF11-B CPU]] - M8189 - QBUS quad-width CPU used in the [[PDP-11/23_PLUS|PDP-11/23+]]
 
*[[KDF11-U CPU]] - M7133 - [[UNIBUS]] hex-width CPU used in the [[PDP-11/24]]
 
*[[KDF11-U CPU]] - M7133 - [[UNIBUS]] hex-width CPU used in the [[PDP-11/24]]
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Like the [[LSI-11]] models, as a cost-reduction measure they do not have a front panel to control them; instead, when the [[CPU]] is halted, specialized [[microcode]] used the main serial line as a operating console. The command set is named Octal Debugging Technique (ODT); there are commands to read and write memory, start the CPU, etc. The main serial interface is normally configured so that when the CPU is running, sending a [[asynchronous serial line|break]] on the console serial line halts the CPU.
  
 
==Floating point==
 
==Floating point==

Revision as of 17:23, 14 January 2017

There are several single-board CPUs which all use the 'Fonz' F-11 chip set:

Like the LSI-11 models, as a cost-reduction measure they do not have a front panel to control them; instead, when the CPU is halted, specialized microcode used the main serial line as a operating console. The command set is named Octal Debugging Technique (ODT); there are commands to read and write memory, start the CPU, etc. The main serial interface is normally configured so that when the CPU is running, sending a break on the console serial line halts the CPU.

Floating point

All the KDF11 CPUs have two choices for floating point support (full PDP-11 FP11 floating point): a on-board single chip, the KEF11-A floating point chip, which implements floating point using microcode; and a higher-performance separate quad board, the FPF11 (M8188).

The FPF11 communicates with the KDF11 via a cable that plugs into the socket on the KDF11 where the KEF11-A is installed; is unusual that it can plug into either a QBUS or UNIBUS backplane, since it only draws power from the backplane - all signals come over the cable to the KDF11.

ODT limitations

The F-11 chip set includes microcode which provides 'front panel' functionality named 'ODT'; the ability to read and write to memory, start the process, etc. However, the original version of the KDF11-A only supported 18-bit addressing, and even though later versions supported 22-bit addressing, ODT in the KDF11's was always limited to 18-bit addressing: i.e. it is impossible to interact with memory above 256 Kbytes from ODT.

The later KDJ11 CPUs do not have this limitation.