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Operation
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Atlas® Digital Amplifier Complete Technical Reference
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0x0, and 0x1. The user sequence can be specified by the user and may contain any values. The user sequence can be
used for any purpose but is often used to identify the type of information stored in the PSF memory space.
Following the eight words of sequence words are one or more data storage blocks known as segments, which are
themselves structured memory blocks which must follow a specific format.
4.13.2 PSF Data Segments
Figure 4-16:
PSF Data
Segment
Format
The central mechanism which PSF provides to store data is called a data segment. PSF data segments come with their
own headers which allow structuring and data integrity checks of the PSF memory space.
shows the
format of a PSF data segment. The following section details each of the elements in this data structure.
Checksum
- is the ones complement of an 8-bit ones complement checksum with a seed of 0xAA. It is computed over
the entire segment space including the header. If the checksum field is computed correctly then the checksum will be
255 (0xff). The size of this field is one byte.
Segment type
- specifies the formatting of the data stored in the segment. This 8 bit field encodes the values 0 through
255. Users may assign segment type values 192-255 for segment types of their own design while all other values are
reserved. The size of this field is one byte.
Data length low word & high word
- contains a 32 bit value encoding the number of 16-bit words of data (data0, data1,
etc…) included with this segment. Data segments can be defined such that a variable number of data words is expected
or a fixed number of words is expected. Whether the number of data words varies or not, the data length word must
always be specified correctly for the number of data words actually contained in the segment.
Identifier
- contains an unformatted 16-bit value that may be used for any purpose but is generally used to identify
separate instances of multiply stored segments of the same segment type. For example if there was an array of stored
segments, each of the same segment type, the identifier field might be used to identify a specific element within of the
overall array of segments.
Data0, Data1, etc…
is the data that is being stored in this segment. The exact format of this data is determined by the
segment type.
Header Word 1
Checksum
Segment Type
Data Length (low)
Identifier
Data Length (high)
Header Word 3
Header Word 2
Header Word 5
Header Word 4
Reserved
Data1
Data2
Data2
Data1
DataN...
DataN...