ADLINK PCI-9820 - Manual (Page 38)

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• Operation Theory
4.7 Synchronizing Multiple Devices
SSI (System Synchronization Interface, please refer to 3.1 for its location)
provides the timing synchronization between multiple cards. Users can
connect a special ribbon cable (ACL-SSI) to all the cards in a daisy-chain
configuration.
The bi-directional SSI I/Os provide a flexible connection between cards,
which allows one SSI master PCI-9820 to output the SSI signals to up to
three slaves PCI-9820s to receive the signals. Table 4.3 lists the summary of
SSI timing signals and the functionalities.
SSI timing signal Functionality
SSI_TIMEBASE Input/Output 60MHz timebase signal through SSI
SSI_TRIG1 Input/Output the trigger signal through SSI
SSI_TRIG2 Input/Output the clocked trigger signal through SSI
SSI_START_OP
Input/Output the acquisition start signal in pre-trigger or mid-
dle-trigger mode
Table 4.3 Summary of SSI timing signals and the corresponding
functionalities
4.7.1 SSI_TIMEBASE
As an output, the SSI_TIMEBASE signal outputs the onboard 60MHz LVTTL
timebase through SSI connector. Note that a timebase generated from ex-
ternal sine wave SMB connector input cannot be routed to SSI_TIMEBASE.
As an input, the PCI-9820 accepts the SSI_TIMEBASE signal to be the
source of timebase.
4.7.2 SSI_TRIG1
As an output, the SSI_TRIG1 signal reflects the trigger event signal in an
acquisition sequence. Please refer to Fig 4.1 - Fig 4.7 for the relationship
between the trigger event and the acquisition sequence. Users can use the
function SSI_SourceConn() to output the SSI_TRIG1 signal.
As an input, the PCI-9820 accepts the SSI_TRIG1 signal to be the trigger
event source. The signal is configured in the rising edge-detection mode.
When selecting the trigger sources of the PCI-9820, Users can select
TRSRC_SSI_1
to set SSI_TRIG1 as the source of trigger event.