MEMO: Wednesday, November 14, 2001
ATLAS Electronics Notes
University of Michigan Physics
Randall Laboratory
TO: ATLAS Muon Front-end Electronics Group
FROM: J. Chapman
RE: How to use new synchronize watches function of AMT-1 MiniDaq
CC: All CSM-0 Users
Purpose of the added code
The AMT-1 has been observed to powerup in two different states that result in dig-
itizations that are 12.5ns different. This is due to separate FFs in the unit for clock
synchronization with the external 40Mhz clock and for digitization. The AMT-2
will not have the feature (attribute/bug whatever). However, for the ASD-lite
boards, it was necessary to add a JTAG instruction (5) that resets the AMT-1 using
the JTAG clock which is derived from the external 40Mhz clock and thus in a
fixed phase relative to it.
To use this reset feature, one must run the new MiniDaq project with the “ synchro-
nize watches” function. This function has a keyboard shortcut Ctrl-w. The function
appears on the JTAG menu as synchronize watches button. This button calls the
function (of the same name) in csm0_daq.c The function turns on the JTAG serial
line and then calls reset_clock located and defined in file jtag_mezzanine.c. The
reset_clock function works by construction of a linked list of JTAG strings that are
few to the JTAG loop using the standard commands defined within MiniDaq for
JTAG programming.
Procedure
It has been observed that MiniDaq requires a cold start following this AMT-1
reset. The reason for this is not clear but will be investigated. Thus the sequence is:
• Start MiniDaq version 1.3.3. with “synchronize watches”
• Load profile
• Synchronize watches
• perform “cold start”
• Enable serial JTAG, program TDC with JTAG, disable serial, & enable TDCs