Front Panel Markers; Interrupt Driven Or Polled Mode Operations; Interrupt Parsing - Keysight E1459A User & Scpi Programming Manual

Installing and Configuring the E1459A

Front Panel Markers

All "Data Available" and "Edge Detect" marker bits are physically available via the
Keysight E1459A front panel. These outputs are TTL/HC compatible and may be
used to trigger other system-wide events or to provide logging information for
statistical tracking or other performance analysis purposes.

Interrupt Driven or Polled Mode Operations

Interrupts may be programmatically disabled for both edge-detect and
data-capture events. All registers remain active and valid and may be serviced on
a polled mode basis.

Interrupt Parsing

Since the command module interrupt handler must service multiple,
concurrently-occurring interrupts, (including those which may be sharing the
same IRQ line), some method is necessary to ensure that only a single IRQ is
posted by the Keysight E1459A during each service interval.
Individual interrupts must be serviced by a commander on a one-for-one basis.
The Keysight E1459A accomplishes this by inhibiting the generation of a second
IRQ each time an IRQ is posted. THE INHIBIT CONDITION IS CLEARED BY THE
REMOVAL AND REASSERTION OF EITHER INTERRUPT ENABLE BIT, "DAV" OR
"EDGE DETECT." (Refer to Figure 2.)
For this one-for-one interrupt parsing, the Keysight E1459A REQUIRES that a
global interrupt enable, either DAV or Edge Detect, be disabled and reasserted
within the context of the interrupt service procedure. Normally, you would simply
shut off interrupts at the top of the service procedure, and would then re-enable
them before returning from service. This is the suggested usage, although this
specific sequence is not necessary for proper Keysight E1459A hardware
function.
18 Keysight E1459A/Z2404B User and SCPI Programming Guide
Functional Description