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This section describes the preliminary design of the ACIS Back End's Detector Electronics Assembly Management software. This software manages commands to the Detector Electronics Assembly subsections, and acquires responses to the commands.
The exact format and content of Detector Electronics Assembly Program RAM and Sequencer RAM loads are TBD. The structure will probably contain one or more blocks, where each block has a DEA subsection selection mask, SRAM/PRAM address, the length of the load, and the data to load. The data will consist of a series of 16-bit words, as defined by the hardware.
Figure 12 illustrates the DEA management scenario.
FIGURE 12. DEA Management Scenario
The Back End software manages commands and status from the Detector Electronics Assembly using a "DEA Manager" class. The DEA manager fields requests from other Back End software elements, translating the requests into one or more DEA commands, forwarding the commands to the "DEA Device" and acquiring the responses to the commands (see Table 9, "`DEA Device' Operations," on page 35). Table 30 lists some of the operations provided by the DEA Manager.
TABLE 30. `DEA Manager'Operations
--------------------------------------------------------------------------------------------- Function Inputs Outputs--------------------------------------------------------------------------------------------- Initialize Address of "DEA Device" to use for none input and output Write to Channel Control Regis Subsystem Identifier(s) none ter Channel identifier Value to write Set D/A Converter Subsystem Identifier(s) none Channel identifier Value to write Read Housekeeping Register Subsystem Identifier The value acquired Channel Identifier from the requested reg ister. Load SRAM Subsystem Identifier(s) none Address to load Length of load Data to load Load PRAM Subsystem Identifier(s) none Address to load Length of load Data to load Read SRAM Subsystem Identifier Data read from Address to read from addressed SRAM Length to read Destination Buffer Read PRAM Subsystem Identifier Data read from Address to read from addressed PRAM Length to read Destination Buffer Start PRAM Cycle Subsystem Identifier(s) Start time of cycle (in Address to start cycle from ACIS time-stamps) Stop PRAM Cycle Subsystem Identifier(s) none CCD Power Disable none none CCD Power Enable Subsystem Identifier(s) none Dump SRAM (TBD) Subsystem Identifier Series of telemetry Address to read from packets containing the Length to read requested information Dump PRAM (TBD) Subsystem Identifier Series of telemetry Address to read from packets containing the Length to read requested information ---------------------------------------------------------------------------------------------
The decision as to whether the "DEA Manager" is responsible for producing SRAM/PRAM telemetry dumps, or if it is a "DEA Housekeeping" operation (using the Read PRAM/SRAM features of the DEA Manager) is TBD.
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