Ocean Optics SAD500 Communications and Control - Manual

SAD500 Serial Port Interface
Communications and Control Information
Overview
The SAD500 Serial Port Interface is a microcontroller-based analog-to-digital converter that interfaces to
Ocean Optics’ S2000 and S1024DW Miniature Fiber Optic Spectrometers and other stackable modules.
When using an RS-232 serial communications protocol, the SAD500 can control all functions of the S2000
and S1024DW spectrometers and implement standard spectral processing. The SAD500 contains non-
volatile flash memory to store spectra and operating parameters. Upon power-up, the SAD500 reads a set
of operating parameters from flash memory. Users can tailor these parameters to satisfy their data
acquisition and processing needs.
Hardware Description
The SAD500 utilizes a 16MHz Motorola 68HC16 microcontroller to control all functions. Digital
communications utilizes RS-232 serial communications with 8 data bits, no parity, and a 1 data bit (8-N-1).
While the majority of the general-purpose I/O pins control the S2000 and S1024DW spectrometers, there
are headers for expansion modules. The available signals are the 7-bit through 10-bit A/D lines, 7 general
purpose digital I/O lines, and the 3 wire Serial Peripheral Interface (SPI) bus with 14 chip selects. Consult
Ocean Optics for custom software to drive these expansion signals.
Upon power-up, the SAD500 transmits the string “Ocean Optics Serial A/D – x”, where x, the error code,
should be 0. It transmits at the baud rate (default 9600 baud) defined in flash memory. The SAD500
operates with three segments of memory: program memory and SRAM and flash memory for data
storage. The user cannot modify the 64KB of program memory. The following describes each data
memory section.
SRAM (Fast) Memory
There are 64KB of SRAM memory used to store data as it is acquired by the SAD500. This section holds
up to 15 full spectral acquisitions consisting of 2048 pixels. Only full spectra are stored in SRAM memory.
Spectra are organized in a stack formation (i.e. LIFO).
Ocean Optics, Inc.
380 Main St.
Dunedin, FL 34698
(727) 733-2447 (727) 733-3962 FAX
http//www.OceanOptics.com
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