Supported module operating modes.

Module operating modes.

The SIS3600 is a 32 bit coincidence register/latch. It therefore has two operating modes (refer to page 27 of the hardware manual);

• Latch mode: In this mode, The leading edge of the external "Next Event" signal latches the state the inputs. The inputs should remains stable throughout the entire duration of the Next Event Pulse.
• Coincidence mode: In this mode, ones are recorded for all bits that undergo a transition to true during the duration of the "Next Event" signal. The bits should remain stable until the Next Event pulse is released.

Note that the module contains a FIFO. It is therefore possible to, e.g. in latch mode, latch in an arbitrary set of inputs. Since the Next Event pulse can be as short as 10ns, in theory, the module could be used to readout some external subsystem at the rate of 10Mhz. Designing systems that function in this way is beyond the scope of this document.

The remainder of this page describes how to setup the module in

• Latch mode.
• Coincidence mode.

and describes the sis3600astClear

Latch mode.

Latch mode is seected by invoking the CSIS3600::SetLatchMode member function. The sample code below expands on the constructor example in Introduction to construct the module and set it into latch mode:

           #include <CSIS3600.h>
        ...
           CSIS3600* pModule(0);       // At program startup, null pointer.
        ...
           void initevt() 
           {
        ...
             if(!pModule) {
               pModule = new CSIS3600(0x36000000, 0);    // Base,crate.
             }
             pModule->SetLatchMode();              // Run in latch mode.
           }

.

Coincidence mode.

Concidence mode is selected by invoking the CSIS3600::SetCoincidenceMode member function. The sample code below expands on the constructor example in Introduction to construct a module and set it into Coincidence mode.

           #include <CSIS3600.h>
        ...
           CSIS3600* pModule(0);       // At program startup, null pointer.
        ...
           void initevt() 
           {
        ...
             if(!pModule) {
               pModule = new CSIS3600(0x36000000, 0);    // Base,crate.
             }
             pModule->SetCoincidenceMode();              // Run in latch mode.
           }

.

Fast clear window.

The module includes support for a fast clear input. If the fast clear input is pulsed within the fast clear window after the falling edge of the "Next Event" signal, no data is transferred to the module fifo for that event.

The fast clear window is setup by first calling the CSIS3600::SetFastClearWindow member function to select a fast clear window size and then calling the CSIS3600::EnableExternalClear member to enable the external fast clear.

Extending the sample codein sis3600Coincidence:

           #include <CSIS3600.h>
        ...
           CSIS3600* pModule(0);       // At program startup, null pointer.
        ...
           void initevt() 
           {
        ...
             if(!pModule) {
               pModule = new CSIS3600(0x36000000, 0);    // Base,crate.
             }
             pModule->SetCoincidenceMode();              // Run in latch mode.
             pModule->SetFastClearWindow(150);           // 150ns fc window.
             pModule->EnableExternalClear();             // Allow fast clears.
           }

Note that the parameter to CSIS3600:SetFastClearWindow is a window width in ns that may be in the range [120ns,25000ns].

---