I was having a bit of trouble getting this
to work the way I wanted it to so I set
up the latch circuit on a proto board
to see if it was doing what I wanted it to do
and when I wanted it to do it.

I whipped up this ZBasic program in a few minutes to test
the CD4011 latch circuit.

public y as long
public x as long
public pin18 as byte
 Sub Main()
for x = 1 to 1000000
 Call PutPin(16, ZXOutputLow)   'set latch
for y = 1 to 50                'delay for a few  usec
next y
Call PutPin(16, ZXOutputHigh)
Debug.Print "   latch is set " 'send to PC
 pin18 = getPin(18)             'read latch output send to PC
Debug.Print "   pin 18 latch output = "; CStr(pin18)
 for y = 1 to 1000000            ' delay for msecs
next y
 'try to reset the latch
Call PutPin(17, ZXOutputLow)   'latch reset
for y = 1 to 50                 'delay for a few  usec
next y
Call PutPin(17, ZXOutputHigh)  'normally high
 for y = 1 to 1000000          ' delay for msecs
next y
 Debug.Print "   latch is reset "  'send to PC
pin18 = getPin(18)               'read latch outpu send to Pt
Debug.Print "   pin 18 latch output = "; CStr(pin18)
 next                        'go back and do it again
 End Sub

I logged the output data in a file on the PC hard disk.

Downloading file
"C:\Documents and Settings\junk\Desktop\ZBasic\Latch-test-only.zxb":
...........................
Download complete.
Verifying download:
...........................
Verification complete.
ZBasic v3.1

Log file:
   latch is set
   pin 18 latch output = 0
   latch is reset
   pin 18 latch output = 1
   latch is set
   pin 18 latch output = 0
   latch is reset
   pin 18 latch output = 1
   latch is set
   pin 18 latch output = 0
   latch is reset

I don't know how I got along in the old days
without this powerful tool. It can do things a scope
cannot do when testing logic circuits. Basically what
it amounts to is a combination of a powerful synchronized
multi-output function generator and a multi-channel scope
all in one low cost instrument.

Paul Lamar