The only public debugger for PCE/TG and CD systems is mednafen (
http://www.mednafen.com). You need to edit the mednafen.cfg file - look for the line for the CD bios path. Put in the path that has your system cards(roms) and save the CFG file.
From there, just type:
mednafen somegame.cue
once the game is running press ALT+D to get into the debugger. Some keys for the debugger interface: "s" to stop or step once instruction at a time, "r" run ( or run until break), shift+enter changes the source address of the short memory display below the disassembler, "enter" changes the starting point for the disassembler , "spacebar" marks a spot for breakpoint in the disassembler window, shift+r breaks on a read addresses ( PC or read instructions ), shift+w breaks on write addresses, control+r breaks on vram read addresses, control+w breaks on vram write addresses, O breaks on opcode(hex value), "F10" resets the system, "F5" save state, "F7" load state. You can use the directional arrows to move around the debugger screen - the action area/sport will be highlighted.
For the read/write CPU break points the address is in hex and is a 16bit address 0x0000-0xFFFF. The CPU actually has a 21bit address bus via use of internal MPR registers. For to break on a specific absolute address, use the * before the address value. So to break on addresses in bank 11, the absolute address of bank 11 is 0x22000 - 0x23FFF. Don't use the C style hex notation just *22000 for absolute or 1BFF for logical address.
when in the debugger alt+1 is the main debugger screen, alt+2 is the tile/sprite viewer, alt+3 is the memory editor.
In the memory editor, press "<" and ">" to go between "RAM" "VCE" "VDC" "PSG" "CPU logical" "CPU physical" "ADPCM".
There are a lot more keys for each more, including dumping an area of memory to a binary file.
As far as the difference between Ziria CD and SCD: the SCD version was recompiled for SCD and the script is compressed so it does use the extra memory of the SCD unit. Dave Shadoff looked into this as part of a translation prospect.