XVME-560 Manual
September, 1984
1.3.1 Analog Circuitry
As can be seen from Figure
l-1,
the application circuitry consists primarily of the
12-
bit A/D converter and its related signal conditioning components listed below:
Multiplexer: directed by software (see Chapter 3) to select one channel for data
conversion.
Buffer (Instrumentation Amplifier): provides a high impedance front end to the
analog signal coming out of the multiplexer.
Programmable Gain: allows a gain of 1, 2, 4 or 8 to be selected for increased
conversion resolution on smaller input signals.
Sample and hold: samples the input signal for 23 usec to allow for “settling
time” in the Instrumentation Amplifier and gain circuitry. This signal is
then "held" until the conversion is completed.
Interrupt circuitry: allows a conversion completion to generate an interrupt (see
Section 3.8).
1.3.2 XYCOM Non-Intelligent Kemel
The Non-Intelligent Kernel is basically the interface to the
VMEbus.
It provides all
the necessary circuitry to receive and generate the signals required by the
VMEbus
specification for a 16-bit slave. By simply adding the application circuitry (in this
case A/D circuitry), a VMEbus module is complete. The Non-Intelligent Kernel has the
following features:
Control and Address Buffers
l
Address Decode circuitry
l
Interrupt Decoder/Driver
l
Control/Status Register
l
Module identification information
lPass and Fail LED indicators
The XYCOM Non-Intelligent Kernel is described in further detail in Appendix A.
1.4
FEATURES OF XYCOM’S STANDARD I/O ARCHITECTURE
The
AIN
and all XYCOM I/O modules conform to the unique XYCOM VMEbus Standard
I/O Architecture. This architecture is intended to make the programming of XYCOM
VMEbus I/O modules simple and consistent. The following features apply to the
operation of the
AIN.
Module Address -The
AIN
can be located at any one of 64 base addresses
in VMEbus Short I/O memory.
l-3
