Difference between revisions of "PAL16L8"

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(Created page with "The CPC6128 second 64K is controlled by a PAL 16L8 chip. The following equations were worked out by: A15OUT = (!X2 & !X1 & A14 # !X3 & !X2 & A14 # A15); !X1 = (!A...")
 
m (→‎Fixed version (Gerald))
(11 intermediate revisions by 4 users not shown)
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The CPC6128 second 64K is controlled by a PAL 16L8 chip.
+
The CPC6128 second bank of 64K RAM is controlled by a PAL 16L8 chip. It has the Amstrad part number 40031.
  
−
The following equations were worked out by:
+
On the CPC 6128 schematic, it is top centre: [http://www.cpcwiki.eu/imgs/4/4a/CPC6128_Schematic.png CPC6128 Schematic] however the X inputs aren't distinguished.
  
−
A15OUT = (!X2 & !X1 & A14
+
== Fixed version (Gerald) ==
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    # !X3 & !X2 & A14
+
Original version from Porchy suffer from a bad handling of the RAMDIS signal. This cause screen artefact when accessing an external extension RAM like XMEM.
−
    # A15);
+
  
−
!X1 = (!A15 & D7ANDD6 & RESET & !IOWR & D0
 
−
    # !X1 & RESET & IOWR
 
−
    # !X1 & !D7ANDD6 & RESET
 
−
    # !X1 & A15 & RESET);
 
  
−
!X2 = (!A15 & D7ANDD6 & RESET & !IOWR & D1
+
A14OUT    = !(  !A14
−
    # !X2 & RESET & IOWR
+
              #  !A15 & !Q0 & Q2 );
−
    # !X2 & !D7ANDD6 & RESET
+
−
    # !X2 & A15 & RESET);
+
A15OUT    = !( !A15 & !A14
 +
              #  !A15 & !Q1
 +
              #  !A15 & !Q0 & !Q2 );
 +
 +
Q0    = (  D7ANDD6 & nRESET & D0 & !A15 & !nIOWR
 +
          #  !D7ANDD6 & nRESET & Q0
 +
          #  nRESET & A15 & Q0
 +
          #  nRESET & nIOWR & Q0 );
 +
 +
Q1    = (  D7ANDD6 & nRESET & D1 & !A15 & !nIOWR
 +
          #   !D7ANDD6 & nRESET & Q1
 +
          #   nRESET & A15 & Q1
 +
          #  nRESET & nIOWR & Q1 );
 +
 +
Q2    = (  D7ANDD6 & nRESET & D2 & !A15 & !nIOWR
 +
          #  !D7ANDD6 & nRESET & Q2
 +
          #   nRESET & A15 & Q2
 +
          #  nRESET & nIOWR & Q2 );
 +
 +
nCAS0    = (  nCAS
 +
            #  RAMDIS & !nCPU & nCAS0
 +
            #  !A15 & A14 & !nCPU & Q2 & nCAS0
 +
            #  A15 & A14 & !nCPU & Q0 & !Q2 & nCAS0
 +
            #  !nCPU & !Q0 & Q1 & !Q2 & nCAS0
 +
            #  !nCAS1 );
 +
 +
nCAS1    = !(  !RAMDIS & !nCAS & !A15 & A14 & !nCPU & Q2 & nCAS0
 +
            #  !RAMDIS & !nCAS & A15 & A14 & !nCPU & Q0 & !Q2 & nCAS0
 +
            #  !RAMDIS & !nCAS & !nCPU & !Q0 & Q1 & !Q2 & nCAS0
 +
            #  !nCAS & !A15 & A14 & Q2 & nCAS0 & !nCAS1
 +
            #  !nCAS & A15 & A14 & Q0 & !Q2 & nCAS0 & !nCAS1
 +
            #  !nCAS & !Q0 & Q1 & !Q2 & nCAS0 & !nCAS1 );
  
−
!X3 = (!A15 & D7ANDD6 & RESET & !IOWR & D2
+
[[File:CPC6128.JED]] : Fixed version of  Amstrad 40031 GAL replacement
−
    # !X3 & RESET & IOWR
+
−
    # !X3 & !D7ANDD6 & RESET
+
−
    # !X3 & A15 & RESET);
+
  
−
!CAS1 = (X3 & !X1 & A15 & A14 & !NCAS & !RAMDIS & !CPU & CAS0
+
[[File:CPC6128.hex]] : Fixed version of  Amstrad 40031 GAL replacement, Hex Intel version.
−
    # !X3 & !A15 & A14 & !NCAS & !RAMDIS & !CPU & CAS0
+
−
    # X3 & !X2 & X1 & !NCAS & !RAMDIS & !CPU & CAS0
+
−
    # !NCAS & CAS0 & !CAS1);
+
  
−
!CAS0 = (X3 & X2 & X1 & !NCAS & !RAMDIS & CAS1
+
== Initial replacement equation (Porchy) ==
−
    # X3 & !X1 & !A15 & !NCAS & !RAMDIS & CAS1
+
−
    # !X3 & A15 & !NCAS & !RAMDIS & CAS1
+
−
    # !X1 & !A14 & !NCAS & !RAMDIS & CAS1
+
−
    # !X3 & !A14 & !NCAS & !RAMDIS & CAS1
+
−
    # !NCAS & !RAMDIS & CPU & CAS1
+
−
    # !NCAS & !CAS0 & CAS1);
+
  
−
A14OUT = (A15 & A14
+
The following equations were worked out by Porchy (member on CPCWiki Forum). These can be used to program replacements:
−
    # !X1 & A14
+
 
−
    # X3 & A14);
+
A15OUT = (!X2 & !X1 & A14
 +
      # !X3 & !X2 & A14
 +
      # A15);
 +
 +
!X1 = (!A15 & D7ANDD6 & RESET & !IOWR & D0
 +
      # !X1 & RESET & IOWR
 +
      # !X1 & !D7ANDD6 & RESET
 +
      # !X1 & A15 & RESET);
 +
 +
!X2 = (!A15 & D7ANDD6 & RESET & !IOWR & D1
 +
      # !X2 & RESET & IOWR
 +
      # !X2 & !D7ANDD6 & RESET
 +
      # !X2 & A15 & RESET);
 +
 +
!X3 = (!A15 & D7ANDD6 & RESET & !IOWR & D2
 +
      # !X3 & RESET & IOWR
 +
      # !X3 & !D7ANDD6 & RESET
 +
      # !X3 & A15 & RESET);
 +
 +
!CAS1 = (X3 & !X1 & A15 & A14 & !NCAS & !RAMDIS & !CPU & CAS0
 +
      # !X3 & !A15 & A14 & !NCAS & !RAMDIS & !CPU & CAS0
 +
      # X3 & !X2 & X1 & !NCAS & !RAMDIS & !CPU & CAS0
 +
      # !NCAS & CAS0 & !CAS1);
 +
 +
!CAS0 = (X3 & X2 & X1 & !NCAS & !RAMDIS & CAS1
 +
      # X3 & !X1 & !A15 & !NCAS & !RAMDIS & CAS1
 +
      # !X3 & A15 & !NCAS & !RAMDIS & CAS1
 +
      # !X1 & !A14 & !NCAS & !RAMDIS & CAS1
 +
      # !X3 & !A14 & !NCAS & !RAMDIS & CAS1
 +
      # !NCAS & !RAMDIS & CPU & CAS1
 +
      # !NCAS & !CAS0 & CAS1);
 +
 +
A14OUT = (A15 & A14
 +
      # !X1 & A14
 +
      # X3 & A14);
 +
 
 +
[[File:Amstrad6128.jed]] Original JED File posted on CPCWiki Forum
 +
 
 +
 
 +
[[Category:Datasheet]]

Revision as of 05:06, 15 June 2019

The CPC6128 second bank of 64K RAM is controlled by a PAL 16L8 chip. It has the Amstrad part number 40031.

On the CPC 6128 schematic, it is top centre: CPC6128 Schematic however the X inputs aren't distinguished.

Fixed version (Gerald)

Original version from Porchy suffer from a bad handling of the RAMDIS signal. This cause screen artefact when accessing an external extension RAM like XMEM. 


A14OUT     = !(  !A14
             #   !A15 & !Q0 & Q2 );

A15OUT     = !(  !A15 & !A14
             #   !A15 & !Q1
             #   !A15 & !Q0 & !Q2 );

Q0     = (  D7ANDD6 & nRESET & D0 & !A15 & !nIOWR
         #   !D7ANDD6 & nRESET & Q0
         #   nRESET & A15 & Q0
         #   nRESET & nIOWR & Q0 );

Q1     = (  D7ANDD6 & nRESET & D1 & !A15 & !nIOWR
         #   !D7ANDD6 & nRESET & Q1
         #   nRESET & A15 & Q1
         #   nRESET & nIOWR & Q1 );

Q2     = (  D7ANDD6 & nRESET & D2 & !A15 & !nIOWR
         #   !D7ANDD6 & nRESET & Q2
         #   nRESET & A15 & Q2
         #   nRESET & nIOWR & Q2 );

nCAS0     = (  nCAS
            #   RAMDIS & !nCPU & nCAS0
            #   !A15 & A14 & !nCPU & Q2 & nCAS0
            #   A15 & A14 & !nCPU & Q0 & !Q2 & nCAS0
            #   !nCPU & !Q0 & Q1 & !Q2 & nCAS0
            #   !nCAS1 );

nCAS1     = !(  !RAMDIS & !nCAS & !A15 & A14 & !nCPU & Q2 & nCAS0
            #   !RAMDIS & !nCAS & A15 & A14 & !nCPU & Q0 & !Q2 & nCAS0
            #   !RAMDIS & !nCAS & !nCPU & !Q0 & Q1 & !Q2 & nCAS0
            #   !nCAS & !A15 & A14 & Q2 & nCAS0 & !nCAS1
            #   !nCAS & A15 & A14 & Q0 & !Q2 & nCAS0 & !nCAS1
            #   !nCAS & !Q0 & Q1 & !Q2 & nCAS0 & !nCAS1 );

File:CPC6128.JED : Fixed version of Amstrad 40031 GAL replacement

File:CPC6128.hex : Fixed version of Amstrad 40031 GAL replacement, Hex Intel version.

Initial replacement equation (Porchy)

The following equations were worked out by Porchy (member on CPCWiki Forum). These can be used to program replacements: 

A15OUT = (!X2 & !X1 & A14
     # !X3 & !X2 & A14
     # A15); 

!X1 = (!A15 & D7ANDD6 & RESET & !IOWR & D0
     # !X1 & RESET & IOWR
     # !X1 & !D7ANDD6 & RESET
     # !X1 & A15 & RESET);

!X2 = (!A15 & D7ANDD6 & RESET & !IOWR & D1
     # !X2 & RESET & IOWR
     # !X2 & !D7ANDD6 & RESET
     # !X2 & A15 & RESET);

!X3 = (!A15 & D7ANDD6 & RESET & !IOWR & D2
     # !X3 & RESET & IOWR
     # !X3 & !D7ANDD6 & RESET
     # !X3 & A15 & RESET);

!CAS1 = (X3 & !X1 & A15 & A14 & !NCAS & !RAMDIS & !CPU & CAS0
     # !X3 & !A15 & A14 & !NCAS & !RAMDIS & !CPU & CAS0
     # X3 & !X2 & X1 & !NCAS & !RAMDIS & !CPU & CAS0
     # !NCAS & CAS0 & !CAS1);

!CAS0 = (X3 & X2 & X1 & !NCAS & !RAMDIS & CAS1
     # X3 & !X1 & !A15 & !NCAS & !RAMDIS & CAS1
     # !X3 & A15 & !NCAS & !RAMDIS & CAS1
     # !X1 & !A14 & !NCAS & !RAMDIS & CAS1
     # !X3 & !A14 & !NCAS & !RAMDIS & CAS1
     # !NCAS & !RAMDIS & CPU & CAS1
     # !NCAS & !CAS0 & CAS1);

A14OUT = (A15 & A14
     # !X1 & A14
     # X3 & A14);

File:Amstrad6128.jed Original JED File posted on CPCWiki Forum

Retrieved from "https://www.cpcwiki.eu/index.php?title=PAL16L8&oldid=103395"