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The Detector Electronics Assembly on ACIS contains a set of hardware settings used to condition the CCD clocks, control the analog signal processing, and set the focal plane and housing temperatures. In addition, ACIS provides the capability to filter bad pixels and columns from generated CCD data. ACIS provides a set of commands a maintainer uses to manage these settings.
Over the life of the instrument, the maintainer may issue commands to ACIS to modify its settings for various DEA clock voltages, processing levels, etc. As the CCDs degrade due to radiation damage, the maintainer may also add pixels and columns to the ACIS Bad Pixel and Column Maps.
The maintainer modifies one or more settings by issuing a "Change System Configuration Settings" command to ACIS. Upon receipt of this command, ACIS updates its configuration parameter block. If a Science Run is in progress when the command is executed, the changes are held until the end of the run, after which they are loaded into the hardware. If no run is in progress, ACIS immediately loads the changes into the hardware.
The maintainer adds items to the Bad Pixel and Column Maps using "Add" commands, and deletes the contents of the maps using the "Reset Map" commands. Upon receipt of these commands, ACIS modifies the appropriate map. Any changes to the Bad Pixel or Column Map will not take effect until the start of the next Science Run.
ACIS shall contain a single set of System Configuration Parameters. Table 37 lists the possible content of this parameter set. The final content depends on the design of the Detector Electronics Assembly, and will be defined in the AS-BUILT ACIS Software Detailed Design Specification, MIT 36-53200. Each individual parameter shall be identifiable using a 16-bit setting code. Each value shall take 16-bits or less to represent. The range of each value are specified by the DEA hardware specifications.
TABLE 37. System Configuration Parameter Set Content (Continued)
------------------------------------------------------------------------------------------------------------ Req Item Description------------------------------------------------------------------------------------------------------------ 37-1 DEA CCD-Controller This items selects which CCD Controller boards within the DEA Power Selection are powered on. 37-2 FEP Power Selection This item selects which Front End Processors are powered on. The remaining parameters consist of DEA board settings. In order to reduce the volatility of the software to changes in the DEA hardware design, the DEA parameter settings are implemented by the software as an array of DEA register settings, leaving the final register function designa tions up to the DEA hardware specification. 37-3 Image Section Phase These items control the high level of the Image Section Phase Clocks High Levels Clocks. The ACIS software loads these levels into the Driver board's clock conditioning Digital-to-Analog converters. These are specified for each CCD. 37-4 Image Section Phase These items control the low level of the Image Section Phase Clocks Low Levels Clocks. The ACIS software loads these levels into the Driver board's clock conditioning Digital-to-Analog converters. These are specified for each CCD. 37-5 Framestore Phase Clocks These items control the high level of the Framestore Phase High Levels Clocks. The ACIS software loads these levels into the Driver board's clock conditioning Digital-to-Analog converters. These are specified for each CCD. 37-6 Framestore Phase Clocks These items control the low level of the Framestore Phase Low Levels Clocks. The ACIS software loads these levels into the Driver board's clock conditioning Digital-to-Analog converters. These are specified for each CCD. 37-7 Serial Output Register These items control the high level of the Serial Output Shift Reg Phase Clocks High Levels ister Phase Clocks. The ACIS software loads these levels into the Driver board's clock conditioning Digital-to-Analog converters. These are specified for each CCD. 37-8 Serial Output Register These items control the low level of the Serial Output Shift Reg Phase Clocks Low Levels ister Phase Clocks. The ACIS software loads these levels into the Driver board's clock conditioning Digital-to-Analog converters. These are specified for each CCD. 37-9 Output Node Reset Gate These items control the high level of the Output Node Reset High Levels Gate. The ACIS software loads these levels into the Driver board's clock conditioning Digital-to-Analog converters. These are specified for each CCD. 37-10 Output Node Reset Gate These items control the low level of the Output Node Reset Gate. Low Levels The ACIS software loads these levels into the Driver board's clock conditioning Digital-to-Analog converters. These are spec ified for each CCD. 37-11 Output Node Reset These items control the level applied to the Output Node's Reset Diodes Diode. These are specified for each CCD. 37-12 Output Node Drains These items control the levels of each of the Output Node Drains. These are specified for each CCD and Output Node. 37-13 Output Node Output These items control the level of the Output Node Output Gates. Gates These are specified for each CCD. 37-14 Output Node Bias Offsets These items control the bias level applied to the Output Nodes. These are specified for each CCD. 37-15 Scuppers These items control the bias-level to the Scuppers. These are specified for each CCD. 37-16 Back-Junction Diodes These items select the levels of the Back Junction Diodes. These are specified for each CCD. 37-17 Bakeout Mode Switch This item controls whether or not bakeout mode is enabled. 37-18 Focal Plane Temperature These items set the focal plane temperature. Set Point (Coarse and Fine) ------------------------------------------------------------------------------------------------------------
ACIS shall provide a command to change one or more system configuration settings. Table 38 illustrates the contents of a Change Settings Command.
TABLE 38. Change Settings Command Packet (Continued)
--------------------------------------------------------------------------------------------------------------- Req Item Description--------------------------------------------------------------------------------------------------------------- 38-1 Packet Length Length of command packet in 16-bit words 38-2 Packet Identifier This is used to identify the command 38-3 Command Opcode Change_Settings_Command opcode 38-4 Settings[Number This is an array of setting entries. The number of entries is determined of entries] using the Packet Length. Each entry has the following format: 38-5 Setting Identifier This is a 16-bit identifier which uniquely identifies the item within the System Con figuration Parameter Block 38-6 Setting Value This the value to use for the specified item. A single setting value shall take no more than 16-bits to represent. ---------------------------------------------------------------------------------------------------------------
Upon receipt of this command, ACIS shall overwrite the System Configuration Parameter Block items as indicated by the entries in the command packet. If no Science Run is in progress, the new settings will be loaded into the hardware immediately. If a Science Run is in progress, the new settings will be loaded after the current run completes. If a setting enables power to a previously un-powered CCD-controller, the corresponding hardware settings are re-loaded into the powered board. If a setting enables power to a previously un-powered Front End Processor, software will power on the corresponding processor and will load and run the default FEP program.
ACIS shall provide a command which allows a maintainer to dump the current contents of the System Configuration Parameter Block. This requirement may be implemented using a Read Back End Memory Command (see Section 3.2.8.3.1 on page 106) or may be implemented using a customized command packet and telemetry representation.
ACIS shall provide a command to add a set of pixels to the Bad Pixel Map. Table 39 describes the Add Bad Pixel Command.
TABLE 39. Add Bad Pixel Command Packet (Continued)
------------------------------------------------------------------------------------------------------ Req Item Description------------------------------------------------------------------------------------------------------ 39-1 Packet Length Length of command packet in 16-bit words 39-2 Packet Identifier This is used to identify the command 39-3 Command Opcode Add_Bad_Pixel_Command opcode 39-4 Pixels[Number of entries] This is an array of setting entries. The number of entries is determined using the Packet Length. Each entry has the follow ing format: 39-5 CCD Identifier This specifies the CCD containing the bad pixel. 39-6 Row and Column These values identify the row and Addresses column within the CCD which is bad, in CCD Coordinates. Summed image pixels which include the specified CCD pixel location are considered bad. ------------------------------------------------------------------------------------------------------
Upon receipt of this command, the ACIS software shall add the listed pixels to its Bad Pixel Map. No attempt is made to eliminate redundant entries.
ACIS shall provide a command to delete the contents of the Bad Pixel Map. Table 40 describes the Reset Bad Pixel Map Command.
TABLE 40. Reset Bad Pixel Map Command Packet (Continued)
-------------------------------------------------------------------
Req Item
Description
Upon receipt of this command, the ACIS software shall remove all pixels from its Bad Pixel Map.
ACIS shall provide a command to dump the contents of its bad pixel map into the telemetry stream. This is accomplished via a "Dump Bad Pixels" command. This command will have the form as shown in Table 41.
TABLE 41. Dump Bad Pixels Command Packet (Continued)
-------------------------------------------------------------------- Req Item Description-------------------------------------------------------------------- 41-1 Packet Length Length of command packet in 16-bit words 41-2 Packet Identifier This is used to identify the command 41-3 Command Opcode Dump_Bad_Pixels_Command opcode --------------------------------------------------------------------
The one or more telemetry packets resulting from this command will contain the information described in Table 42. This requirement may be implemented using a Read Back End Memory Command (see Section 3.2.8.3.1 on page 106) or may be implemented using a customized telemetry representation.
TABLE 42. Dumped Bad Pixel Map Telemetry Content (Continued)
------------------------------------------------------------------------------------------------------- Req Item Description------------------------------------------------------------------------------------------------------- 42-1 Packet Synch This field marks the start of the ACIS packet within the teleme try stream. 42-2 Packet Word Length This field indicates the number of 32-bit words in the packet. 42-3 Format Tag This field indicates the type of data contained in the telemetry packet, in this case a Timed Exposure Bad Pixel Map Dump packet. 42-4 Packet Sequence Number This field is used to sequentially number all ACIS telemetry packets. 42-5 Command Packet Identifier This is the Packet Identifier of the command causing the dump being performed. This allows the ground to associate the com mand and the resulting telemetry packets. 42-6 Pixels[Number of entries] This is an array of setting entries where each entry has the fol lowing format. 42-7 CCD Identifier This specifies the CCD containing the bad pixel. 42-8 Row and Column These values identify the row and Addresses column within the CCD which is bad -------------------------------------------------------------------------------------------------------
Upon receipt of a Dump Bad Pixels Command, the ACIS Back End software shall form and send one or more telemetry packet containing the current list of bad pixels for all CCDs.
ACIS maintains two bad column maps, one for Timed Exposure Mode, and one for Continuous Clocking Mode. ACIS shall provide a command to add a set of columns to either Bad Column Map. Table 43 describes a generic Add Bad Column Command.
TABLE 43. Add Bad Column Command Packet (Continued)
----------------------------------------------------------------------------------------------------------------- Req Item Description----------------------------------------------------------------------------------------------------------------- 43-1 Packet Length Length of command packet in 16-bit words 43-2 Packet Identifier This is used to identify the command 43-3 Command Opcode Mode-specific Add_Bad_Column_Command opcode 43-4 Columns[Number of entries] This is an array of setting entries. The number of entries is deter mined using the Packet Length. Each entry has the following format: 43-5 CCD Identifier This specifies the CCD containing the bad column. 43-6 Column Address This value identifies the bad column within the CCD. Summed image pixels which include the specified CCD column are considered bad. -----------------------------------------------------------------------------------------------------------------
Upon receipt of this command, the ACIS software shall add the listed columns to the Bad Column Map indicated by the opcode. No attempt is made to eliminate redundant entries.
ACIS shall provide a command to remove all columns from a Bad Column Map. Table 44 describes a generic Reset Bad Column Command.
TABLE 44. Reset Bad Column Map Command Packet (Continued)
--------------------------------------------------------------------------- Req Item Description--------------------------------------------------------------------------- 44-1 Packet Length Length of command packet in 16-bit words 44-2 Packet Identifier This is used to identify the command 44-3 Command Opcode Mode-specific Reset_Bad_Column_Command opcode ---------------------------------------------------------------------------
Upon receipt of this command, the ACIS software shall remove all pixels from the Bad Column Map indicated by the opcode.
ACIS shall provide a command to dump the contents of a bad column map into the telemetry stream. This is accomplished via a "Dump Bad Columns" command. This command will have the form as shown in Table 41.
TABLE 45. Dump Bad Columns Command Packet (Continued)
------------------------------------------------------------------------- Req Item Description------------------------------------------------------------------------- 45-1 Packet Length Length of command packet in 16-bit words 45-2 Packet Identifier This is used to identify the command 45-3 Command Opcode Mode-specific Dump_Bad_Columns_Command opcode -------------------------------------------------------------------------
The one or more telemetry packets resulting from this command will contain the information described in Table 42. This requirement may be implemented using a Read Back End Memory Command (see Section 3.2.8.3.1 on page 106) or may be implemented using a customized telemetry representation.
TABLE 46. Dumped Bad Column Map Telemetry Content (Continued)
------------------------------------------------------------------------------------------------------------------ Req Item Description------------------------------------------------------------------------------------------------------------------ 46-1 Packet Synch This field marks the start of the ACIS packet within the telem etry stream. 46-2 Packet Word Length This field indicates the number of 32-bit words in the packet. 46-3 Format Tag This field indicates the type of data contained in the telemetry packet, in this case a Continuous Clocking Bad Column Map Dump packet. 46-4 Packet Sequence Number This field is used to sequentially number all ACIS telemetry packets. 46-5 Command Packet Identifier This is the Packet Identifier of the command causing the dump being performed. This allows the ground to associate the command and the resulting telemetry packets. 46-6 Columns[Number of entries] This is an array of setting entries where each entry has the fol lowing format: 46-7 CCD Identifier This specifies the CCD containing the bad column. 46-8 Column This value identifies the column within the Address CCD which is bad ------------------------------------------------------------------------------------------------------------------
Upon receipt of a Dump Bad Columns Command, the ACIS Back End software shall form and send one or more telemetry packet containing the current list of bad columns for all CCDs.
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