L2 & L3 Data from L1Cal

updated: 12-Jun-04

General L2 Data Format

See also the Level 2 Trigger Hardware page and Run IIa L1Cal to L2 data list.

Type	19	18	17	16	15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00
H	0	1	0	1	Header Length								No. of Objects
H	0	0	0	0	H Format			Obj Format					Object Length
H	0	0	0	0	Crossing No. (L1_BX)								L2 Data Type
H	0	0	0	0	Turn No. (L1_TURN)
H	0	0	0	0	Firmware Min Ver								Firmware Maj Ver
H	0	0	0	0	L2 Status								Processor Bits

D	0	0	0	0	Data
D	0	0	0	0	---
D	0	0	0	0	Data

T	0	0	0	0	L2 Data Type								Crossing No. (L1_BX)
T	0	0	0	0	Vertical Parity

P	0	0	0	0	Pad (0)
P	0	0	0	0	---
P	1	0	1	0	Pad (0)

L2 Data from the TABs

Each TAB sends to L2/L3 the raw TT Et's it receives from the ADFs. The TAB Global Chip is in charge of transferring this data to the G-Link transmitter on each TAB. Only data is shown, headers, trailers, pads and control bits as above.

No.	15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00
1	EM(39,5)								H(39,5)
2	EM(39,4)								H(39,4)
3	EM(39,3)								H(39,3)
4	EM(39,2)								H(39,2)
5	EM(38,5)								H(38,5)
	---								---
160	EM(0,2)								H(0,2)

L2 Data from the GAB

The GAB sends to L2/L3 some processed information and the trigger terms it sends to the framework. Given below is one possible data format. The exact nature of the processed data that can be sent is limited by the data that is transmitted between the TABs and the GAB. Only data is shown, headers, trailers, pads and control bits as above.

No.	15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00
1	Mask of EM Clust's over L2 Thr: eta=N, phi=31-16
2	Mask of EM Clust's over L2 Thr: eta=N, phi=15-0
3	Mask of EM Clust's over L2 Thr: eta=C, phi=31-16
4	Mask of EM Clust's over L2 Thr: eta=C, phi=15-0
5	Mask of EM Clust's over L2 Thr: eta=4, phi=31-16
6	Mask of EM Clust's over L2 Thr: eta=4, phi=15-0

7	Mask of JET Clust's over L2 Thr: eta=N, phi=31-16
8	Mask of JET Clust's over L2 Thr: eta=N, phi=15-0
9	Mask of JET Clust's over L2 Thr: eta=C, phi=31-16
10	Mask of JET Clust's over L2 Thr: eta=C, phi=15-0
11	Mask of JET Clust's over L2 Thr: eta=S, phi=31-16
12	Mask of JET Clust's over L2 Thr: eta=S, phi=15-0

13	Mask of TAU Clust's over L2 Thr: eta=N, phi=31-16
14	Mask of TAU Clust's over L2 Thr: eta=N, phi=15-0
15	Mask of TAU Clust's over L2 Thr: eta=C, phi=31-16
16	Mask of TAU Clust's over L2 Thr: eta=C, phi=15-0
17	Mask of TAU Clust's over L2 Thr: eta=S, phi=31-16
18	Mask of TAU Clust's over L2 Thr: eta=S, phi=15-0

19	Sum(EM+H Et)
20	Sum(EM+H Ex)
21	Sum(EM+H Ey)

22	Trigger Terms 63-48
23	Trigger Terms 47-32
24	Trigger Terms 31-16
25	Trigger Terms 15-0

Timing

L2/L3 Data is tranferred from each of the TAB's and the GAB using a G-Link transmitter running in 20-bit mode (with 16 data bits per cycle). The clock rate for this transmitter is 53 MHz leading to a bit transmission rate of 1.06 Gbit/s.

Total transfer times are given below.

Board TAB/GAB Internal G-Link Xmit Time Total Time
(from L1Accept)

TAB 1.4 us
(SW-->Global) [6(header) + 160(data) + 2(trailer) + 0(pad)] / 53Mhz = 3.17 us 4.6 us

GAB 0 [6(header) + 25(data) + 2(trailer) + 7(pad)] / 53Mhz = 0.75 us 0.8 us

Notes

Transmission is by G-link in 20-bit mode. The highest order 4 bits are used to flag begin and end of event.
L2 Data transimission must be padded to a multiple of 8, 20-bit words
Each TAB is responsible for a 40x4 (etaxphi) region of EM and H data. The 4 phi's it sends out correspond to phi-inputs 2-5 (out of 0-8)

Board	TAB/GAB Internal	G-Link Xmit Time	Total Time (from L1Accept)
TAB	1.4 us (SW-->Global)	[6(header) + 160(data) + 2(trailer) + 0(pad)] / 53Mhz = 3.17 us	4.6 us
GAB	0	[6(header) + 25(data) + 2(trailer) + 7(pad)] / 53Mhz = 0.75 us	0.8 us