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User's Manual (MUT)
Mod. V977 16 Channel I/O Register (Status A)
27/08/2004
1
NPO:
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00118/01:V977X.MUTX/01
V977_REV1.DOC
21
9
3. Operating modes
3.1. Functional description
The Mod. V977 is a 16 channel general purpose I/O Register or as Multihit Pattern Unit
The following figure shows the simplified scheme of a single channel:
OUTPUT
CH #n
OUTPUT
OR
OUTPUT
OR
TO IRQ
LOGIC
INPUT
CH #n
INPUT READ
VME REGISTER
CONTROL
REGISTER
PATTERN BIT
INPUT
GATE
INPUT MASK
VME REGISTER
INPUT SET
VME REGISTER
CONTROL
REGISTER
GATE MASK BIT
1
0
D
Q
AR
1
D
Q
AR
SINGLE HIT READ
VME REGISTER
MULTIHIT READ
VME REGISTER
1
0
OUTPUT MASK
VME REGISTER
OUTPUT SET
VME REGISTER
1
0
CONTROL
REGISTER
OR MASK BIT
INTERRUPT MASK
VME REGISTER
FROM TEST
CHANNEL
LOGIC
CLEAR OUTPUT
VME REGISTER
INPUT
CLEAR
AR
Fig. 3.1: Mod. V977 channel structure
The core of each channel is composed by a couple of FLIP -FLOPs, which perform the
memory functions. The two cascaded FLIP -FLOPs, as shown in Fig. 3.1, allow to detect
the following events: none, one or two input hits. The FLIP-FLOPs status of all channels
can be read via VME, in the SINGLEHIT READ REGISTER and MULTIHIT READ
REGISTER, which are related respectively to the first and to the second cascaded
FLIP_FLOP. The content of such register can also be read by accessing the SINGLEHIT
READ-CLEAR REGISTER and MULTIHIT READ-CLEAR REGISTER: in this case the
FLIP -FLOPs are cleared after readout.
The FLIP-FLOPs of all channels can also be cleared both via VME, by accessing the
CLEAR OUTPUT REGISTER, and via the front panel CLEAR signal.
The FLIP FLOPs are set either via an input hit or via VME write access (INPUT SET
REGISTER). By accessing the CLEAR OUTPUT REGISTER, the INPUT SET
REGISTER is cleared.
The capabilty of receiving input hits can be masked via VME through the INPUT MASK
REGISTER (individually for each channel), or via the input GATE signal (common to all
channels), which can be masked in its turn.
The status of the inputs can also be read directly vi a VME in the INPUT READ
REGISTER.
The status of the channel LEDs and of the outputs depend on the module’s programming.
