Changes
/* Technical */
One half (256K) of the total (512K) expansion memory can be accessed as Video RAM (with normal expansions, only 64 KB are accessible as VRAM). This is making the expansion slightly incompatible with the dk'tronics standard. However, usually expansion memory is mapped to 4000h-7FFFh, whilst VRAM is usually mapped to C000h-FFFFh. So, most existing software may work with it, without accidently displaying garbage on the screen.
== Installation Guid ==
=== Components ===
16x 41256 (256Kx1 DRAM) ;replacing the CPC6128's 16 built-in 64Kx1 DRAMs
1x PAL 16L8 ;replacing the CPC6128's 16 built-in PAL
1x 74LS38 (Quad 2-input NAND, OC)
1x 74LS273 (8bit latch, of which only 6bit are used here)
1x 2200 Ohm resistor
1x 470 Ohm resistor
1x 47 Ohm resistor
=== Step 1 - Replacing the RAM ===
The old 64Kx1 DRAMs have same pin-outs as the new 256Kx1 ones (except, pin 1 was NC on old chips, on new chips it's A8 of RAS:CAS addresses; aka A16,A17 of linear addresses).
* Replace the old RAMs by the new RAMs.
* Wire pin 1 (formerly NC) of all RAMs to GND (allowing to test the circuit after Step 1) (later on, it will be wired to RAS:CAS A8 in Step 2).
=== Step 2 - Daughterboard Logic ===
The original article has been confusing on this part. It basically said that one needs "four additional connections", but without giving too clear info on which signals are to be connected to which locations.
* Replace the old PAL by the new daughterboard (containing the new PAL, and the 2 logic chips and 3 resistors).
== Missing Info ==
