The following holds for any readout mode except RAW. As explained in Sec. 1.5.2, the SIFE bank is substructured by means of Control Words that mark the beginning of a data block for one PPC. After the first word follow nine more header words having the following format and meaning for the CST:
CST Main PPC Control Word
bbMMMSpp'ppmmmmmm'mmllllll'llllllll
b: 2-bit branch = 00 (CST), 01 (BST1), 10 (VLQ)
M: 4-bit SiMode word: 0 = DATA, 1 = COPYRAW, 3 = MONI, 4 = EXTRA
S: if set, Specials are present in the data
p: 4-bit PPC number
m: 8-bit FADC wanted mask
l: 14-bit length of PPC data (in long words). Max 32 kB = 8k words.
-------------------------
CST PPC data header
1 HitFinding Time (16 MHz counter)
2 Updating Time (16 MHz counter)
3 Event Number (24bit) | PIC
4 Raw Address
5 Bit Mask for pending PPC raw buffers
6 Version number
7 reserved
8 reserved
9 reserved :
This header is always present.
The PPC data block is then again substructured with respect to data from the different FADCs. At the top of each ``FADC Data Block'' there is again a Header word (the CST FADC Control Word) which contains the length of the block and the FADC number.
These FADC data blocks can contain different information: Hits, Raw data, Pedestals, Sigmas or the Common Modes (for 10 connected APCs). The CST FADC Control Word has the following format:
CST Block Control Word
00000000'WtttfffV'llllllll'llllllll
t: 3-bit data type: 000-Hits, 001-Raw, 010-CM, 011-Ped, 100-Sigma
f: 3-bit FADC number (0-7)
V: Voltages on/off (detected by checking Specials)
l: 16-bit length of FADC data block (in long words)
----------------------------------------
The complete output in the different readout modes is as follows:
| CST PPC data header (10 words) | ||
| CST Hit data block(s) (for all selected FADCs) | ||
One CST FADC Hit data block has the following format:
| CST FADC Block Control Word (type Hit) | ||
| CST Hit Data Words | ||
| 8 CST Special Words | ||
with the following data words:
CST Hit Word
ssssssss'sssDDDDD'DDDDDppp'pppppppp
s: 11-bit scaled variance, scaled by 1/4
D: 10-bit pulse height ( RAW - PED - CM)
p: 11-bit strip number
----------------------------------------
CST Special Word
10000fff'DDDDDDDD'DDDDDppp'pppppppp
f: 3-bit FADC number
D: 13-bit RAW data
p: 11-bit "strip"-number (1280-1287)
----------------------------------------
The Special words are present only every other event. This is indicated by bit 26 of the CST Data Header Word.
An additional feature meant for debugging is the possibility to have one Raw data block (format see below) between the Hit data blocks. This is limited to one FADC of the whole CST (bandwidth!). It can be selected from the Supervisor panel:
: FADC no. RIO no.
If both numbers have been non-zero, the Raw data block will be inserted after the Hit data block of the selected FADC. To make its recognition easier, bit 23 of the FADC Control word of the Hit data block will be set and will be telling us: Expect the next data block to be of type Raw for the same FADC!
| CST PPC data header (10 words) | ||
| CST Raw Data Block(s) (for all selected FADCs) | ||
--------------------------------------------
Format of a CST Raw Data Block:
CST Block Control Word (fixed length = 740)
strip 0 | strip 1
strip 2 | strip 3
: | :The Monitor mode offers a possibility to have hit data as well as raw data available offline. Furthermore, the used constants are written out, so that the performance of the PowerPC hitfinding routine can be checked. Due to data size considerations, the Monitor mode only processes data of one FADC which can be selected at the System Supervisor (s.a. Sec 1.4.3):
: first number (upper 4 bits of SiRESERVED[0])
| CST PPC data header (10 words) | ||
| CST Hit data block | ||
| CST Raw Data block | ||
| CST Common Mode block | ||
| CST Pedestal block | ||
| CST Sigma block | ||
----------------------------------------------
Format of a CST Common Mode Block:
CST Block Control Word (fixed length = 10)
CM APC 0
CM APC 1
:
----------------------------------------------
Format of a CST Pedestal Block:
CST Block Control Word (fixed length = 1280)
strip 0 'Old' Pedestal, this PIC
strip 1
:
----------------------------------------------
Format of a CST Sigma Block:
CST Block Control Word (fixed length = 1280)
strip 0 'Old' scaled sigma**2
strip 1
:
It is immediately understandable that in this mode only data of one FADC can be treated (see Sec. 2.2: FADC masks).