Return GTRC   Return GLAST
GTRC Commands and Register

Commands

The commands to the controller are described. Each command consists of a command header followed by a data section. For most of the command a standard data format is used. The data is 68 bits longed followed by one bit for odd parity. There are some commands which don't have any data section at all, and for the readevent command the data section is only 2 bits long.

The following tables show all the commands to the controller. Some of the commands are forwarded by the controller to the front-end chips connected to the controller. Controller chips are addressed by a 4-bit address whereas front-end chips are addressed by 5 bits. The MSB of the address is sent first. The following conventions are used:

gggg
Four bit GTRC address.
fffff
Five bit GTFE address
F
Function code: F=0 command only to GTRC, F=1 command forwarded to GTFE.
P
Command parity bit. Odd parity of the gtrc-, gtfe address and the function code.
D
Data parity. Odd parity for the 68 bit data section.
DATA
68 bits data section.
  1. Commands to the GTRC only
  2. Commands to the GTFE
  3. Read event sequence, token and tack

Commands only to the GTRC

cmd bits comments
NOOP 1 gggg 0 xxxxx 00000 P  
Reset gtrc 1 gggg 0 xxxxx 00001 P   DATA   D  
LD_GTRC_REG 1 gggg 0 xxxxx 01000 P   DATA   D Load GTRC register.
LD_GTFE_SYNC 1 gggg 0 xxxxx 01001 P   DATA   D read GTRC register. No data section.
RD_GTRC_REG 1 gggg 0 xxxxx 10000 P read GTRC register. No data section.
RD_GTFE_SYNC 1 gggg 0 xxxxx 10001 P read Gtfe sync register. No data section.
Commands to the GTRC only. The GTFE address (xxxxx) is ignored.

Commands to the GTFE

cmd bits comments
RST_CHIP_GTFE 1 gggg 1 fffff 00010 P  
CALIBRATE 1 gggg 1 fffff 00011 P  
LD_DATA_MASK 1 gggg 1 fffff 01000 P   DATA   D  
LD_CAL_MASK 1 gggg 1 fffff 01001 P   DATA   D  
LD_TRIG_MASK 1 gggg 1 fffff 01010 P   DATA   D  
LD_DAC 1 gggg 1 fffff 01011 P   DATA   D  
LD_MODE 1 gggg 1 fffff 01100 P   DATA   D  
RD_DATA_MASK 1 gggg 1 fffff 10000 P read GTFE data-mask register. No data section.
RD_CAL_MASK 1 gggg 1 fffff 10001 P read GTFE calibration-mask register. No data section.  
RD_TRIG_MASK 1 gggg 1 fffff 10010 P read GTFE trigger-mask register. No data section.  
RD_DAC 1 gggg 1 fffff 10011 P read GTFE threshold/calibration dac register. No data section.  
RD_MODE 1 gggg 1 fffff 10100 P read GTFE direction/deaf register. No data section.
Commands forwarded to GTFE. The four bits gggg are the GTRC address (MSB most left bit). fffff is the GTFE address (MSB is the most left bit).

Read-event Sequence, Token and Tack

Read Event 1 gggg 1 fffff 00100 P 1B1B0 Start read-event sequence
Pcmd

Register

B[67-0] S[0-67] R[33-0] (33-R) Value Comment
67 0   1 Separator Bit
66-51 1-16   not used  
50 17   1 Separator Bit
35 32 33(0) LD_FT enable load FORCE and TOT values
34 33 32(1) LD_DELAY enable load READ_DELAY value
33 34   1 Separator Bit
32 35 31(2) LD_STRETCH enable load STRETCH value
31 36 30(3) LD_CNT enable load GTFE_CNT value
30 37 29(4) LD_SIZE enable load SIZE value
29 38 28 SUM_ERR Logical or of TAG, TRIG, DAT and CMD error. (Read only)
28 39 27 CMD_ERR Commnad parity error. (Read only)
27 40 26 DAT_ERR Data parity error. (Read only)
26 41 25 TRIG_ERR L1T parity erorr. (Read only)
25 42 24 TOK_ERR Token parity error. (Read only)
24 43 23 TAG_ERR TAG Erorr, from reading TAG's from GTFE. (Read only)
23 44 22(11) SHIFT_MODE Bonded pad to determine side. (Read only)
22 45 21(12) TOT_EN 1 => Enable ToT Delay. Readout to DAQ waits until trigger is low or trigger counter expired.
21 46 20(13) FORCE_NO_ERR 0 => Normal operation, 1 => Forces normal event readout.
20-18 47-49 19-17(14-16) READ_DELAY Delay from Read-Event to start of read command to GTFE.
17 50 16(17) OR_STRETCH[4] MSB of the OR_STRETCH, see B15-B12.
16 51   1 Separator bit
15-12 52-55 15-12(18-21) OR_STRETCH[3..0] Fast-Or Stretch in counts of the clock cycle. 0: No deglitch, no stretch
11-7 56-60 11-7(22-26) GTFE_CNT Number of GTFE chips to read.
6-0 61-67 6-0(27-33) SIZE Maximum number of hits from GTFE.
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Wilko Kroeger
 Last modified: Fri Jun 1 15:45:26 PDT 2001
Last modified: Tue Dec 11 19:52:40 PST 2001