Keithley 486 Instruction Manual page 152

SECTION 6
Thmy
of
operation
'igure 6-12. A/D Converter Simplified Schematic
6.6 DIGITAL CIRCUITS
423) and shows some information that does
not pertain to the Model 486/487.
The paragraphs below give an overview of the digital cir-
cuits, whkh can Lx found on drawing numbers 487-146
and486-116 (487-116fortheModel487) at tbeend of Sec-
tion 8.
6.5.1
Digital Block Diagram
NOTE
Thedigitalboardshownindrawing487-146is
also used for a different instrument (Model
Figure 6-13 shows a block diagram of the most important
circuits. Key sections in&de the microcomputer (RAM,
ROM, VIA, EFXOM, and GPL41, the display board, and
the IEEE-488 interface. The various sections are covered
in the following peqqaphs.
6-9