Changes
/* Why I destroyed the PPL */
else b"1111" when RAMbank="111" and (A(15)='0' and A(14)='1')
else b"10" & A(15 downto 14); -- default value
* '''Ghouls'n'Ghost.dsk''': black screen during game. RAM is not relaxed enought to permit changing address just after knowing if Z80 does a read or a write (ROM written=> does write on RAM hidden behind)
== Effort done ==
A schematic developed in order to be comparable to original documentation schematic is nice. FPGAmstrad is composed of 3 schematics :
* amstrad_motherboard : comparable to original Amstrad schematic.
* amstrad_video : does manage a true VGA output, using a an internal VRAM.
* bootloader_sd : sdcard bootloader, in order to load ROM and dsk at boot, from sdcard.
attribute clock_signal of key_reset : signal is "NO";
And tadam, less than half of hour to compile now ! and on a determinist way.
This formula does run also on bus (dsk_info bus wire coming from SDRAM_FAT32_LOADER to simple_DSK)
=== Internal FPGA RAM (VRAM) config ===
The internal dual RAM (written at 4MHz by Z80 and readden at 25MHz by VGA) are configured as "WRITE FIRST", "READ DOESN'T CARE".
aZRaEL_vram2vgaAmstradMiaow.vhd (the VRAM to VGA output part) has several manual counter offset calibrations, called "bug_*", it seems this component does not know counting right when reaching 25MHz (in fact it is, "mod" instruction does suffer a lot by here)
=== palette_D and aZRaEL's counters derailment ===
Compiler does detect when somes wires of a bus are not used, and when this bus is scanned by several counter derailing it results some data missing (this pixels normaly come from this offset, but is finaly calibred at this offset, so I plug it here and compiler does not thrust me, saying it's plug to an unused wire so does compile all that to GND... black screen)
Solution : using all wires of palette_D, taking care the compiler does not remove an "useless" wire from bus, and do calibrate manualy the derailing counters (all that "bug_*" constants inside aZRaEL_vram2vgaAmstradMiaow.vhd)
== Source code ==
