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This defines the interfaces between the various processing stages.  These are currently AXI streaming interface. These are the processing stages

• Sanitizier → Descrambler
• Descrambler → Corrector
• Corrector → Convolver/RoiSelector

It is assumed that the outbound stream of the previous stage is the inbound stage of the subsequent stage.

Sanitizier → Descrambler Stream

The AXI stream is defined as

These widths of WUser, Wid and WDest  are taken from the surf defaults.

NOTE: shlsip only uses WUser, so WDest could be set to 0 to save resources

The width of the Data field depends to the configuration.  

• In a 2 x 1 configuration of the ASICS → 192 bits
  • 2 Asics * 6 Streams/Asic * 16 bit/data word   
• In a 4 x 1 configuration of the ASICS → 384 bits
  • 4 Asics * 6 Streams/Asic * 16 bit/data word

Frame

The sanitizer will organize its output into frames composed of a number of the AXI streaming words defined above.  Each frame will contain all the tile data associate with one 'image. The sideband data fields, WUser and the last value are used to identify the Start Of Frame (SOF), End of Frame with Errors (EOFE) and the last word in the frame (last) 

NOTE: The value of TUser field on the last word in the frame depends of whether there are no errors in the frame (0) or has errors (1).

Frame Contents - Proposal

The The first word of the frame shall be a header word followed by the data.

The header will contain fields identifying

• Frame Sequence Number (32 bits)
• ASIC identification.           TBD bits)
• XXX

Each data word will contain 6 x 16 bit words for each ASIC, so 12 x 16 bits for a 2 x 1 and 24 x 16 bits for a 4 x 1 arrangement. The 16-bit word itself shall be formatted as

NOTE: Dionisio at one time indicated that the ASIC returns the data with the gain bit in Bit 0 with the sanitizer moving it to Bit 15. In fact, it is more convenient for the gain bit to be in bit 0.  When the correction, which involves subtracting a dark image value, is done, the result is. that 14-bit unsigned ADC value goes to a 15-bit signed value.  It is more natural that the sign bit occurs in its customary MSB.