MAX Machine PLA equations (correct this time)

From: Michał Pleban <*lists_at_michau.name*> Date: Fri, 02 Sep 2016 20:32:58 +0200 Message-ID: <57C9C5DA.4050303@michau.name> · lists_at_michau.name

Hello!

After spending two weeks on the MAX Machine PLA dump I made earlier,
finally I decided to abandon it and start again. I suspect the PLA did
not read properly in the EPROM burner, maybe because it was too slow.

So I decided to write the equations myself from scratch. I burned a
22V10 with these equations and MAX Machine works perfectly with them. I
tested the PLA replacement with the MultiMAX cartridge as well as
several original cartridges I own, and I did not find any problems. So
here are my equations (note that BUF is an additional signal to control
a 4066 chip for COLOR RAM):

!RAM = !A11 & !A12 & !A13 & !A14 & !A15 & CLK & BA
 # !A11 & !A12 & !A13 & !CLK
 # !A11 & !A12 & !A13 & !BA;

!EXRAM = A11 & !A12 & !A13 & !A14 & !A15 & CLK & BA
 # A11 & !A12 & !A13 & !CLK
 # A11 & !A12 & !A13 & !BA;

!ROML = !A13 & !A14 & A15 & CLK & BA;

!ROMH = A13 & A14 & A15 & CLK & BA
 # A12 & A13 & !CLK
 # A12 & A13 & !BA;

!SID = A10 & !A11 & A12 & !A13 & A14 & A15 & CLK & BA;

!VIC = !A10 & !A11 & A12 & !A13 & A14 & A15 & CLK & BA;

!COLRAM = !A10 & A11 & A12 & !A13 & A14 & A15 & CLK & BA
 # !CLK
 # !BA;

BUF = !A10 & A11 & A12 & !A13 & A14 & A15 & CLK & BA;

!CIA = A10 & A11 & A12 & !A13 & A14 & A15 & CLK & BA;

!RW_OUT = CLK & !RW_IN;

If anyone is interested, I can post my working Eagle PCB as well.

Regards,
Michau.

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