More Strobe Lines !


After the 8 data lines are hooked up there are only 4 more output lines available to be used as strobe lines. Although this is enough to control some PTS symthesizers, you will need more lines for some other models or if you intend to control multiple PTS units. There are several options to generate more strobe lines.

1 - Install another printer port.

2 - Use an address decoder to expand the 4 lines that are available.

I used an address decoder as I wanted to save the other printer ports for controlling other devices.

Using the remaining 4 output lines a 7442 can be used to generate 9 strobe lines. This is enough to control two PTS-160 or a PTS-500 and a PTS160.

A 4515 CMOS / 74154 TTL device can be used to generate 15 strobe lines. This can control 3 PTS-500, 3 PTS-160 or any combination of these.

The 7442 appears to be more readily found in the junk box but if you are buying your decoder chip new look for the CD4515 / MC14515. The 4515 is NOT an expensive chip. Many suppliers sell this chip for as low as $0.25 each.

+5 vdc to power the decoder is available on Pin 48 of the parallel remote plug on the back of the PTS synthesizer.


7442 TTL
1-of-10 inverting decoder/demultiplexer

This will generate 9 strobe lines from 4 address lines.
S0,S1,S2,and S3 go to the 4 output lines from the computer.
/Y1 through /Y9 are the 9 strobe lines to the PTS.
/Y0 is reserved for the 'OFF' state.
This chart has NOT been verified!

    +----------+
/Y0 |1       16| VCC 
/Y1 |2       15| S0 
/Y2 |3       14| S1 
/Y3 |4       13| S2 
/Y4 |5  7442 12| S3 
/Y5 |6       11| /Y9 
/Y6 |7       10| /Y8 
GND |8        9| /Y7 
    +----------+
  S3 S2 S1 S0   /Y0 /Y1 /Y2 /Y3 /Y4 /Y5 /Y6 /Y7 /Y8 /Y9
Pin 12 13 14 15   1 2 3 4 5 6 7 9 10 11
Dec 8 4 2 1   0 1 2 3 4 5 6 7 8 9
Hex 08 04 02 01   00 01 02 03 04 05 06 07 08 09
  0 0 0 0   0 1 1 1 1 1 1 1 1 1
  0 0 0 1   1 0 1 1 1 1 1 1 1 1
  0 0 1 0   1 1 0 1 1 1 1 1 1 1
  0 0 1 1   1 1 1 0 1 1 1 1 1 1
  0 1 0 0   1 1 1 1 0 1 1 1 1 1
  0 1 0 1   1 1 1 1 1 0 1 1 1 1
  0 1 1 0   1 1 1 1 1 1 0 1 1 1
  0 1 1 1   1 1 1 1 1 1 1 0 1 1
  1 0 0 0   1 1 1 1 1 1 1 1 0 1
  1 0 0 1   1 1 1 1 1 1 1 1 1 0

CD4515, MC14515, CMOS
1-of-16 inverting decoder/demultiplexer with address latches.
This will generate 15 strobe lines from 4 address lines.
S0,S1,S2,and S3 go to the 4 output lines from the computer.
/Y1 through /Y15 are the 15 strobe lines to the PTS.
/Y0 is reserved for the 'OFF' state
Note: Pin 23 /EN must be grounded to enable the chip!
Pin 1 LE should be tied to (high) VCC at pin 24.
This chart has been verified!
    +----------+
 LE |1       24| VCC  
 S0 |2       23| /EN  
 S1 |3       22| S3   
/Y7 |4       21| S2   
/Y6 |5       20| /Y10 
/Y5 |6       19| /Y11 
/Y4 |7  4515 18| /Y8  
/Y3 |8       17| /Y9  
/Y1 |9       16| /Y15 
/Y2 |10      15| /Y14 
/Y0 |11      14| /Y12 
GND |12      13| /Y13 
    +----------+
  S3 S2 S1 S0   /Y0 /Y1 /Y2 /Y3 /Y4 /Y5 /Y6 /Y7 /Y8 /Y9 /Y10 /Y11 /Y12 /Y13 /Y14 /Y15
Pin 22 21 3 2   11 9 10 8 7 6 5 4 18 17 20 19 14 13 15 16
Dec 8 4 2 1   0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Hex 08 04 02 01   00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
  0 0 0 0   0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
  0 0 0 1   1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1
  0 0 1 0   1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1
  0 0 1 1   1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1
  0 1 0 0   1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1
  0 1 0 1   1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1
  0 1 1 0   1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1
  0 1 1 1   1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1
  1 0 0 0   1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1
  1 0 0 1   1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1
  1 0 1 0   1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1
  1 0 1 1   1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 1
  1 1 0 0   1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1
  1 1 0 1   1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1
  1 1 1 0   1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1
  1 1 1 1   1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0

74154

This will generate 15 strobe lines from 4 address lines.
A,B,C,and D go to the 4 output lines from the computer.
/Y1 through /Y15 are the 15 strobe lines to the PTS.
/Y0 is reserved for the 'OFF' state.
This chart has NOT been verified!

    +----------+
/Y0 |1       24| VCC  
/Y1 |2       23|  A   
/Y2 |3       22|  B   
/Y3 |4       21|  C   
/Y4 |5       20|  D   
/Y5 |6       19| /G2  
/Y6 |7 74154 18| /G1  
/Y7 |8       17| /Y15 
/Y8 |9       16| /Y14 
/Y9 |10      15| /Y13 
/Y10|11      14| /Y12 
GND |12      13| /Y11 
    +----------+
Ground G1 and G2
to enable the chip !
  D C B A   /Y0 /Y1 /Y2 /Y3 /Y4 /Y5 /Y6 /Y7 /Y8 /Y9 /Y10 /Y11 /Y12 /Y13 /Y14 /Y15
Pin 20 21 22 23   1 2 3 4 5 6 7 8 9 10 11 13 14 15 16 17
Dec 8 4 2 1   0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Hex 08 04 02 01   00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
  0 0 0 0   0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
  0 0 0 1   1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1
  0 0 1 0   1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1
  0 0 1 1   1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1
  0 1 0 0   1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1
  0 1 0 1   1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1
  0 1 1 0   1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1
  0 1 1 1   1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1
  1 0 0 0   1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1
  1 0 0 1   1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1
  1 0 1 0   1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1
  1 0 1 1   1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 1
  1 1 0 0   1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1
  1 1 0 1   1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1
  1 1 1 0   1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1
  1 1 1 1   1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0

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