Sun Microsystems S16A manual Overview

S16A User’s Guide Overview

Overview

The S16A SBus 16-bit Dual Analog Interface is a single-slot board for SBus-based computer systems. The S16A has two analog I/O channels, each incorporating one 16-bit Analog-to-Digital (ADC) converter and one 20-bit Digital-to-Analog (DAC) converter. The S16A is designed for continuous input and output on both channels simultaneously and is typically used for scientific and medical research and development.

The S16A employs two Burr-Brown®PCM1702 analog output DACs running at a sample rate of 705.6KHz, which is 16 times the standard audio frequency of 44.1 KHz.

The two S16A analog input ADCs are National Semiconductor® ADC16071s, running with a base sampling rate of 192KHz. The S16A provides a clock prescale register to divide this frequency down for lower rates.

The S16A uses the SBus DMA interface and can transmit or receive any amount of data to and from host memory continuously on both channels at once.

Each I/O channel’s input ADC can monitor a differential signal, either of the two differential inputs as a single-ended signal, either of two I/O channels’ DAC outputs, or a reference ground. The ability to monitor the outputs directly or ground allows the S16A to be tested and adjusted using these internal loop-backs.

A portion of the functionality of the S16A is contained in a sub-assembly, the Analog Input Module. This module is controlled and configured using a byte-sequence protocol, as described in the section Analog Input Module Control Protocol beginning on page 34.

The S16A boards fully support the requirements of the SunOS operating system. Example programs are included. Each of the two I/O channels appears as two subdevices to the SunOS operating system, one for input and one for output, for a total of four subdevices.

This document explains how to install the S16A interface and driver and how to write applications for it. It is divided into the following sections:

Installation	describes how to install the board and its related software.
Input and Output	describes the programming interface library.
Hardware Interface Protocol	provides a connector pin-out diagram and describes the S16A signals
	and timing.
Registers	describes the hardware registers.
Specifications	lists the product specifications.
References	lists other documentation resources that may be helpful.
Contacting EDT	describes how to contact EDT, and how to access EDT resources on the
	Internet.

EDT, Inc. October, 1996 1