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CFabr1's avatar
CFabr1
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4 years ago

Implementing old PAL/GAL into HDL

Hi all,
I'm porting into Quartus some old schematics for CPLD/FPGA implementation.This old hardware made of TTL gates but there are also some PLDs (GALs and PALs) that I have fusemap of.Some of them are pure combinatorial logics and perhaps I know how to write a Verilog module (just matter of declaring the I/O and put equations for each output).But others PLDs are registered so they have sequential logics inside (a clock and an output enable pin).So, I'm looking for some help about.Thanks in advance for any tip/suggestion/example.

3 Replies

  • RichardT_altera's avatar
    RichardT_altera
    Icon for Super Contributor rankSuper Contributor
    4 years ago

    Hi @CFabr1

    If I understand your question correctly, you would like to convert the schematic file into HDL Design file?

    Do you able to open the schematic file in Quartus? If so, Go to File–>Create/Update–>Create HDL Design File… and choose the file type (Verilog/VHDL) that you would like to convert to.

    Best Regards,
    Richard Tan

    p/s: If any answer from the community or Intel support are helpful, please feel free to give Kudos.

    • CFabr1's avatar
      CFabr1
      Icon for New Contributor rankNew Contributor
      4 years ago

      I' trying to translate into Verilog some PAL/GAL devices.I have done this with combinatorial logics but now I'm stuck because I'm dealing with sequential logics.Here's the disassembling of a registered PAL which I want to port in Verilog, you can see there are four regitsered outputs (with clock and OE) 

      /** Inputs **/
      Pin	2 = i2;
      Pin	3 = i3;
      Pin	4 = i4;
      Pin	5 = i5;
      Pin	6 = i6;
      Pin	7 = i7;
      Pin	8 = i8;
      Pin	9 = i9;
      Pin	12 = i12;
      Pin	13 = i13;
      Pin	14 = i14;
      Pin	15 = i15;
      Pin	16 = i16;
      Pin	17 = i17;
      Pin	18 = i18;
      Pin	19 = i19;

      /** Outputs **/
      Pin	12 = o12; /**(Combinatorial, Output feedback output, Active low) **/
      Pin	13 = o13; /**(Combinatorial, Output feedback output, Active low) **/
      Pin	14 = o14; /**(Registered, Output feedback registered, Active low) **/
      Pin	15 = o15; /**(Registered, Output feedback registered, Active low) **/
      Pin	16 = o16; /**(Registered, Output feedback registered, Active low) **/
      Pin	17 = o17; /**(Registered, Output feedback registered, Active low) **/
      Pin	18 = o18; /**(Combinatorial, Output feedback output, Active low) **/
      Pin	19 = o19; /**(Combinatorial, Output feedback output, Active low) **/

      /** Equations **/

      !o12 = o13;
      o12.oe = vcc;

      !o13 = o17 & o18
           # o16 & !o18 & !o19;
      o13.oe = vcc;

      !o14 .d !i2
            # i2 & !i4 & o14
            # i2 & i4 & !o14;
      o14.oe = OE;

      !o15 .d !i2
            # i2 & !i4 & !i5 & !o14 & o15
            # i2 & !i4 & i5 & o14 & o15
            # i2 & i4 & !i5 & o14 & o15
            # i2 & i4 & !o14 & !o15
            # i2 & i5 & !o14 & !o15
            # i2 & !i4 & !i5 & o14 & !o15
            # i2 & i4 & i5 & o14 & !o15;
      o15.oe = OE;

      !o16 .d !i2
            # i2 & !i5 & o15 & o16
            # i2 & !i4 & !i5 & o14 & o16
            # i2 & i5 & !o16
            # i2 & i4 & !o15 & !o16
            # i2 & !o14 & !o15 & !o16;
      o16.oe = OE;

      !o17 .d !i2
            # i2 & !i3 & i6 & o17
            # i2 & !i3 & o17
            # i2 & !i5 & i6 & o17 & !o19
            # i2 & i3 & i5 & !o17
            # i2 & i3 & !i6 & !o17
            # i2 & i3 & !o17 & o19
            # i2 & !i6 & !o17 & o19;
      o17.oe = OE;

      !o18 = i3 & o17
           # !i3 & !o17 & o19;
       

      !o19 = !i4 & o15 & o16
           # !i4 & o14 & o16;