Readout Protocol for TileCal Digitizer

NOTE:  In the version described here channels 1,2,3 are readout from boards 1
       to 8, followed by channels 4,5,6 from boards 1 to 8.  The current plans
       call for reading all 6 channels from one board before advancing to the
       next.  The writeup for the new version will be substituted when
       available.

April 1998


Headerword (from board 1)            --
Dataword (1)                          |
Dataword (2)                          |
Dataword (3)                          |
...                                   |
Dataword (samples-1)                  |
Dataword (samples)                    |   Datawords contain channels 1,2,3
Vertical parity (odd)                 |   
Headerword (from board 2)             |
Dataword (1)                          |
...                                   |
(board 3)                             |
...                                   |
(board 8)                            --
(board 1)                             |   Data words contain channels 4,5,6
...                                   |   
(board 8)                            --

16 sets of data is read out for every level1 two from each of the eight boards.


HEADERWORD:

 headerindicator
 | parity
 | | parity_error
 | | | read_error
 | | | | tec_error
 | | | | |     DEstr
 | | | | |     | SEstr
 | | | | |     | | hi/low_flags
 | | | | |     | | |     mode
 | | | | |     | | |     |   board_nr
 | | | | |     | | |     |   |     data_set_nr
 | | | | |     | | |     |   |     | not used
 | | | | |     | | |     |   |     | |   bunch_crossing_id
 | | | | |     | | |     |   |     | |   |
 _______________________________________________________________
|1| | | | | | | | | | | | | | | | | |X|X| | | | | | | | | | | | |


DATAWORD

   parity
   | data_1              data_2              data_3
   | |                   |                   |
 _______________________________________________________________
|0| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |


headerindicator:
Is set to 1 to separate from data and vertical parity.

parity:
Parity bit (even parity).

parity_error:
Parity error detected in the controller from the tec_dmu's.

read_error:
Some tec_dmu failed to send data.

tec_error:
Indicates a tec_dmu that has the wrong memory number (of five) and thus the
 wrong data.

DEstr:
A Double Error Strobe recieved from the ttc.

SEstr:
A Single Error Strobe recieved from the ttc.

hi/low_flags:
Indicates high(1) or low(0) amplification from the pm-tube.

mode:
00 - normal mode
01 - calibration mode
     Both high and low amplification is read out.
10 - test mode
     A test word is read into the tec_dmu and read back to the controller.
11 - not used

board_nr:
The board the data is from.

data_set_nr:
Indicates if the data is from the first three(0) or the last three(1) tec_dmu's
on the board.

bunch_crossing_id:
Bunch crossing identifier.

data_1:
data from the first or forth of the tec_dmu's.

data_2:
data from the second or fifth of the tec_dmu's.

data_3:
data from the third or sixth of the tec_dmu's.

/Jonas Klereborn     klere@grub01.physto.se