AB Soft Mercury 3000Si manual Operational Modes Trigger Approach Timing Diagram

Operational Modes: Trigger Approach Timing Diagram

The Trigger Approach can be used in applications where synchronization of the position data to an event is required. Often, this mode is used when a fixed latency between a clock signal and the sampled position data is required. The customer can choose this mode of operation by using the optional SmartPrecision Software. In this mode, triggering is controlled by the n_spiEnable signal.

The falling edge of n_spiEnable signal starts the process by immediately resetting the internal calculators and acquiring the latest A/D converter information. Old data in the calculation chain is discarded and the initiation of a new position calculation is started. The new data is ready in 1420ns. The n_spiEnable signal for retrieving the data must be asserted within 210ns after the new data is ready or the triggered acquisition will be over written by new data.

Shifting the data out of the interpolator's serial port is accomplished exactly as in the Standard Communication mode of operation. In order to sample the next position, n_spiEnable must be brought high and then reasserted. See the Trigger Approach timing dia- gram below.

Trigger Approach Timing Diagram

tW

tCS

n_spiEnable

	tTDR	tCSC		tspiH	tspiL
spiClock				Clk1
		tCSD				tV
spiDataOut
			MSB

tCCS

Clk36

LSB

Trigger Approach Timing Diagram

Symbol	Parameter	Minimum	Typical	Maximum	Units
tspiH	spiClock High Time	50			ns
tspiL	spiClock Low Time	50			ns
tTDR	￿n_spiEndable to DataReady	1420		1600	ns
tW	￿n_spiEnable Low for trigger	50			ns
tCSC	n_spiEnable to ￿spiClock	0
tCSD	￿n_spiEnable to DataValid		80		ns
tV	￿spiClock to Data Valid		80		ns
tCCS	￿spiClock to ￿n_spiEnable	0			ns
tCS	n_spiEnable High	50			ns

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