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C't 512 KB internal RAM expansion

28 bytes added, 13:03, 8 May 2010
/* PAL Source Code */
== PAL Source Code ==
D7D6 D0 D3 D4 D1 D2 NCAS A15 A14 GND ;pin 1..10 CPU A15S AMUX MUX LCLK CAS1 CAS0 IOWR A14S VCC ;pin 11..20
IF (VCC) /LCLK= D7D6 * /A15 * /IOWR ;load external latch on OUT [7Fxxh],C0h..FFh
IF (VCC) /CAS0= /NCAS * /D4 + ;bank bit4=0, select bank 0..15 (CPU and CRTC)
/CAS0= /NCAS * A15 +
/CAS0= /NCAS * /A14 +
/CAS0= /NCAS * CPU
IF (VCC) /CAS1= /NCAS * D4 * /A15 * A14 * /CPU ;bank bit4=1, select bank 16..31 (CPU at 4000h..7FFFh only)
IF (VCC) /A14S= /A14 + ;bank bit0
6,388
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