User Manual

2400 Series SourceMeter
®
User’s Manual Limit Testing 12-11
Digital output lines
The four output lines output a specific bit pattern based on the pass/fail results of
the various limit tests. (See “Types of limits,” page 12-2.) In the 3-bit output mode,
Line 4 can also be used either as an end-of-test (EOT) or BUSY signal depending
on the END OF TEST mode. (See “Configuring limit tests,” page 12-16.)
EOT or Busy Line
In the 3-bit mode, line 4 can be used to flag the handler when the digital I/O lines
may be read. Depending on the type of handler present, either BUSY or end-of-
test (EOT) may be used. These signals are defined as follows:
BUSY — The BUSY signal indicates the time from which the start-of-test (SOT)
signal is received until all measurements, limit testing, and digital I/O operations
have been completed. When /BUSY is selected, line 4 goes LO during this time
period.
NOTE The arm source must be set to SOT in order to use BUSY.
EOT — The end-of-test strobe signals to the handler that the digital I/O lines may be read.
This pulse occurs approximately 10us after the SourceMeter(c) has updated the digital I/O
lines and ends approximately 10us before the digital I/O lines actually clear. The EOT
pulse width is specified by the digital auto clear delay. EOT is HI when the digital I/O is
updated. /EOT goes LO after the digital I/O lines are updated.
NOTE Digital auto-clear myst be enabled in order to use EOT.
SOT line
The input line (SOT) of the Digital I/O is used to control the start of the testing pro-
cess. For remote operation with
↓STEST selected as the arm event of the trigger
model, the testing process will start when the SOT line is pulsed low. When
↑ STEST is the selected arm event, the testing process will start when the SOT
line is pulsed high. When
↑↓STEST is selected, testing will start when SOT is
pulsed either high or low. For front panel operation with the IMMEDIATE arm
event selected, the testing process will start as soon as the LIMIT key is pressed
(assuming the output is ON). See Section 11, “Triggering,” for details on trigger
model configuration.
When using the SOT line, the handler will not pulse the line while it is in a not
ready condition. When the handler is ready (DUT properly positioned in the han-
dler), it pulses the SOT line low or high to start the test.
/OE line
The /OE (output enable) line of the Digital I/O can be used if the component han-
dler is equipped with a switch. With proper use, power is removed from the DUT