Changes
Although I have taken the utmost care preparing this documentation, I am no electronics engineer and did this only as a hobby project. I do not guarantee that it is error free and I accept no responsibility for damage to anyone’s hardware or other personal equipment or injury inflicted on you or others.
== Construction of the 320K version (no PAL programming required) version ==
The required logic can either be built on a slim breadboard or with the help of a PCB that plugs into the PAL socket.
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== Construction of the 320/512K version (PAL programming required) version ==
For a 512K version the biggest challenge is, that when we replace also the first bank we must treat the first 64K as base RAM and the other 192K as extended RAM in a way that it is properly recognised by software.
* 2x Pin header 1x10
* 2x capacitor 100nF
* 2x ATF16V8 (or other PAL16L8 compatible ICs)- [https://www.cpcwiki.eu/imgs/f/f7/CPC_6512jed.zip JED files]
The assembly is pretty much identical to the PCB description above with the following changes:
* There is a connection from the PCB to D5. D5 is e.g. pin 29 on the 40007 socket. For other options check the schematics/Pinouts.
Note: It's also possible to use this PCB as for a 320K versionmod. In that case only replace the second (left) RAM bank and connect the D5 pad to GND (throughhole through hole directly next to the D5 pad).
[[File:CPC6512 1.jpg|thumbnail|left]] [[File:CPC6512 2.jpg|thumbnail|right]] [[File:CPC6512 3.jpg|thumbnail|none]]
PAL1:
<small><pre>
/* *************** INPUT PINS *********************/
PIN 1 = Q0 ; /* */
PIN 2 = RAMDIS ; /* */
PIN 3 = Q1 ; /* */
PIN 4 = Q2 ; /* */
PIN 5 = Q3 ; /* */
PIN 6 = Q4 ; /* */
PIN 7 = Q5 ; /* */
PIN 8 = A15 ; /* */
PIN 9 = A14 ; /* */
PIN 11 = nCPU ; /* */
PIN 15 = nCASADR ; /* */
PIN 16 = nCAS ; /* */
/* *************** OUTPUT PINS *********************/
PIN 12 = A15OUT ; /* */
PIN 13 = BANKING ; /* */
PIN 14 = A8 ; /* */
PIN 17 = nCAS1 ; /* */
PIN 18 = nCAS0 ; /* */
PIN 19 = A14OUT ; /* */
A14OUT = !( !A14
# !A15 & !Q0 & Q2 );
A15OUT = !( !A15 & !A14
# !A15 & !Q1
# !A15 & !Q0 & !Q2 );
nCAS0 = ( nCAS
# !nCAS1
# !nCPU & nCAS0 & RAMDIS
# !nCPU & nCAS0 & BANKING & !Q5
);
BANKING = ( !A15 & A14 & Q2
# A15 & A14 & Q0 & !Q2
# !Q0 & Q1 & !Q2);
nCAS1 = !( !nCAS & nCAS0 & !nCPU & !A15 & A14 & Q2 & !Q5 & !RAMDIS
# !nCAS & nCAS0 & !nCPU & A15 & A14 & Q0 & !Q2 & !Q5 & !RAMDIS
# !nCAS & nCAS0 & !nCPU & !Q0 & Q1 & !Q2 & !Q5 & !RAMDIS
# !nCAS & nCAS0 & !A15 & A14 & Q2 & !Q5 & !nCAS1
# !nCAS & nCAS0 & A15 & A14 & Q0 & !Q2 & !Q5 & !nCAS1
# !nCAS & nCAS0 & !Q0 & Q1 & !Q2 & !Q5 & !nCAS1 );
A8 = ( Q5 & BANKING & !Q3 & !nCASADR & !nCPU
# Q5 & BANKING & !Q4 & nCASADR & !nCPU
# Q5 & BANKING & Q3 & Q4 & !nCPU
# !Q5 & BANKING & Q3 & !nCASADR & !nCPU
# !Q5 & BANKING & Q4 & nCASADR & !nCPU
);
</pre></small>
PAL2:
<small><pre>
/* *************** INPUT PINS *********************/
PIN 1 = D6D7 ; /* */
PIN 2 = D0 ; /* */
PIN 3 = nRESET ; /* */
PIN 4 = D1 ; /* */
PIN 5 = D2 ; /* */
PIN 6 = D3 ; /* */
PIN 7 = D4 ; /* */
PIN 8 = D5 ; /* */
PIN 9 = A15 ; /* */
PIN 11 = nIOWR ; /* */
/* *************** OUTPUT PINS *********************/
PIN 13 = Q5 ; /* */
PIN 14 = Q4 ; /* */
PIN 15 = Q3 ; /* */
PIN 16 = Q2 ; /* */
PIN 17 = Q1 ; /* */
PIN 18 = Q0 ; /* */
Q0 = ( nRESET & D6D7 & !A15 & !nIOWR & D0
# nRESET & !D6D7 & Q0
# nRESET & A15 & Q0
# nRESET & nIOWR & Q0 );
Q1 = ( nRESET & D6D7 & !A15 & !nIOWR & D1
# nRESET & !D6D7 & Q1
# nRESET & A15 & Q1
# nRESET & nIOWR & Q1 );
Q2 = ( nRESET & D6D7 & !A15 & !nIOWR & D2
# nRESET & !D6D7 & Q2
# nRESET & A15 & Q2
# nRESET & nIOWR & Q2 );
Q3 = ( nRESET & D6D7 & !A15 & !nIOWR & D3
# nRESET & !D6D7 & Q3
# nRESET & A15 & Q3
# nRESET & nIOWR & Q3 );
Q4 = ( nRESET & D6D7 & !A15 & !nIOWR & D4
# nRESET & !D6D7 & Q4
# nRESET & A15 & Q4
# nRESET & nIOWR & Q4 );
Q5 = ( nRESET & D6D7 & !A15 & !nIOWR & D5
# nRESET & !D6D7 & Q5
# nRESET & A15 & Q5
# nRESET & nIOWR & Q5 );
</pre></small>
== References and links ==
