Anritsu 373XXA manual PCB Assembly

SYSTEM DESCRIPTION DIGITAL SUBSYSTEM ASSEMBLIES

￿ System boot-up EPROM – This chip contains the boot-up instruc- tions used by the system CPU at power-up.

A13 I/O Interface #1 This PCB assembly performs the following functions:

PCB Assembly	￿ Floppy drive control – interface for the Floppy Drive Assembly.
	￿ External Keyboard control – interface for the front panel Key-
	board connector.
	￿ Interface for the A18 Rear Panel PCB Assembly (below).
	￿ Interface and control for the rear panel IEEE 488.2 GPIB and
	Dedicated GPIB interface connectors.

A14 I/O Interface #2 This PCB assembly contains a State Machine controller, decode logic, and PCB Assembly bus interface control circuits that perform the following functions:

￿Quiet Bus interface control. The Quiet Bus passes control and data signals from the A9 Main Processor PCB to the A1 – A8, and A21 PCBs and returns status and data signals back to the A9 PCB. This bus is managed by the control circuits on the A14 PCB such that it is inactive during the the time that a measure- ment is being taken.

NOTE

The output data from the A5 PCB A/D converter is sent to the A9 Main Processor PCB via the Quiet Bus, the A14 PCB, and the VME Bus.

￿A/D Bus interface control. During the measurement process, all A/D selection and conversion functions on the A5 PCB are con- trolled exclusively by the A14 PCB State Machine Controller.

This is accomplished via the command lines of the A/D Bus.

￿Measurement control functions – the A14 PCB State Machine Controller manages many of the 373XXA functions during a mea- surement, as follows:

￿Quiet Bus interface control

￿A/D Bus interface control:

￿Sample and Hold control for A5 PCB

￿A/D selection and conversion control for A5 PCB

￿Check for phase lock condition

￿Gain ranging

￿Delay generation for IF Bandwidth setting function

The A14 PCB also provides the interface to the Front Panel A19 and

A20 PCBs

373XXA MM 7-15