Tektronix 372, User Manual

Page: 278 / 364

Sample Programs
Reference
3Ć166
The fourth example illustrates how to control the TTL I/O function. In this
program, external equipment connected to the TTL I/O port on the rear
panel of the instrument. Requirements for this equipment are:
1. A TTL I/O port which can be connected to the 372 via a cable. This TTL
I/O interface, which provides 1 bit outgoing line (IN BIT 0) and 5 bits
incoming parallel signals (OUT BIT 0 to 4), has same pinout and signal
name as the TTL I/O interface of the 372. Note that the IN/OUT direcĆ
tions are different between the equipment and the 372. For the pinout
and signal name of the 372 TTL I/O, refer to Appendix F.
2. There is a foot pedal which asserts IN BIT 0 in the TTL I/O port and
resets the indicators described below when stepped.
3. There is FAIL indicator which is lit when the 00001 TTL signal is received
from the TTL I/O port. This indicator can be used to inform the operator
that GONOGO testing has failed.
4. There is a PASS indicator which is lit when the 00000 TTL signal is
received from the TTL I/O port. This indicator can be used to inform the
operator that a GONOGO testing has passed.
5. The IN BIT 0 in the TTL I/O port is unasserted when the 00001 or 0000
TTL signal is received.
The program \BJT\PRG_BJT5.PRG loads setup file, executes the ICEO vs.
VCEO measurement and performs GONOGO testing. When the GONOGO
testing fails, the instrument outputs the 00001 TTL signal from the TTL I/O
port on the rear panel, and lights the FAIL indicator on the external equipĆ
ment. When the GONOGO testing passes, the instrument outputs the 00000
TTL signal from the TTL I/O on the rear panel, and lights the PASS indicator
in the external equipment.
Measurement and GONOGO testing are performed repeatedly until the
[STOP] button on the front panel of the instrument is pressed. It is also
assumed that the operator exchanges the BJT and steps the foot pedal
when the measurement is ready.
Example 4