Operating instructions

SEA M300USERSGUIDE
MAINWINDOW  66
The information for the IRQ and Proxy times are from the counters on the system board. When we
do acquisition using the PC clock as a time source for acquisition, we assume there is no system
board present. So all values pertaining to IRQ and Proxy would be zero.
The basic information displayed here is the times for IRQ handler and times for Proxy handler.
At the user selected frequency from the system board table, the M300 generates an interrupts for
acquisition (IRQ 3). This is the engine for the acquisition process.
While in the IRQ handler the OS can’t schedule other tasks. To stay real-time, we must keep the
time in the IRQ handler as short as possible. So we kick a Proxy to handle the acquisition work.
All the acquisition work is done in the Proxy handler.
So we display latency and duration here for both IRQ and Proxy. We display current value,
minimum values, maximum values for all these.
IRQLatency
The IRQ interrupt latency is the time from the assertion of a hardware interrupt to the start of the
interrupt handler.
IRQDuration
This is the amount of time it took to process the last interrupt.
ProxyLatency
The Proxy latency is the time from the end of the interrupt handler to the start of the Proxy handler.
ProxyDuration
This is the amount of time it took to process the Proxy handler. Since we do all the acquisition in the
Proxy, this is the time it took to do all the acquisition.
IRQError
The M300 system can determine giving the timing information for system frequency, IRQ and
Proxy if there are errors associated with the IRQ.
This field must be 0 during acquisition. Any errors here and the user must investigate the source of
the errors. High frequency value, many acquisition events, spending too much time on displays can
be the cause of these problems.
ProxyError
The M300 system can determine giving the timing information for system frequency, IRQ and
Proxy if there are errors associated with the Proxy.
This field must be 0 during acquisition. Any errors here and the user must investigate the source of
the errors. High frequency value, many acquisition events, spending too much time on displays can