19-11-2019, 06:25 PM
Having acquired a Microbee 256TC, it came quite evident that many of the Microbee arcade games do not work on it because of the different keyboard access routines required compared to the original Microbees.
Not being a coder, what to do to overcome the problem. Using a hex editor, maybe I could locate the old keyboard access routine and over write it with some 256tc keyboard code. Reading the programming_notes_on_the_256tc.pdf (in the Documentation/Manuals folder) it has :-
XBIOS function 15 : kb test
Usage:
ld c,key_code
ld a,15
rst 28h
This function checks to see if the key, whose code is in the C register, is currently down on the keyboard. If it is down it returns with the Z flag set, if it is up it returns with NZ status. This is the same as in the original code.
The many people that converted or fixed a number of TRS-80 games to run on the Microbee, all/most seemed to have used the keyboard routine from the Wildcards Vol 3 book (which appears to have come from the BASIC 5.10 rom). So all I needed to do was open the file in a HEX Editor, locate the old keyboard code (first 4 bytes of the keyboard code are C5 4F 47 3E) and overwrite all the keyboard code with C5 4F 3E 0F EF C1 C9 followed by lots of 00's to overwrite all the rest of the old code. Tried it first with Volcano Hunter and it worked, so tried it on others where there was no ASM code available for the games. Where ASM code was supplied, I simply replaced the keyboard access code and recompiled. Even Mytek used the same/similar code in some of their games.
As a result, I have been able to make up a bootable menu driven disk full with 28 games that all work ONLY on a Microbee 256TC. There are 2 games that didnt need any conversion, Target (Colour version) and Hopper.
I can also confirm that the copy protected Honeysoft disks of type t4 (have full colour menus), such as honeysoft_penny_arcade_t4.dsk, all work on the Microbee 256TC as well as earlier Microbee's. So none of those games are included here. The types t1, t2 & t3 only work on earlier Microbee's.
The 28 games on this disk are :-
Alien Cresta
Apple Panic
Battle Station
Centipede Attack
Cosmic Fighter
Defence Command
Galaxy Invasion
Galaxy Invasion Plus
Ghost Hunter
Hopper
Hoppy
Jungle Raiders
Killer Beetles
Meteor Mission I
Meteor Mission II
Killopede
Minedrop II
Munch
Outhouse
Penetrator
Gun Fighter
Sea Dragon
Target - Colour version
Tandy Invaders
Volcano Hunter
Asteroids Plus
Car Race
So in the Microbee/Software/Games folder we placed
256tc_arcade_games_ds80.dsk
Not being a coder, what to do to overcome the problem. Using a hex editor, maybe I could locate the old keyboard access routine and over write it with some 256tc keyboard code. Reading the programming_notes_on_the_256tc.pdf (in the Documentation/Manuals folder) it has :-
XBIOS function 15 : kb test
Usage:
ld c,key_code
ld a,15
rst 28h
This function checks to see if the key, whose code is in the C register, is currently down on the keyboard. If it is down it returns with the Z flag set, if it is up it returns with NZ status. This is the same as in the original code.
The many people that converted or fixed a number of TRS-80 games to run on the Microbee, all/most seemed to have used the keyboard routine from the Wildcards Vol 3 book (which appears to have come from the BASIC 5.10 rom). So all I needed to do was open the file in a HEX Editor, locate the old keyboard code (first 4 bytes of the keyboard code are C5 4F 47 3E) and overwrite all the keyboard code with C5 4F 3E 0F EF C1 C9 followed by lots of 00's to overwrite all the rest of the old code. Tried it first with Volcano Hunter and it worked, so tried it on others where there was no ASM code available for the games. Where ASM code was supplied, I simply replaced the keyboard access code and recompiled. Even Mytek used the same/similar code in some of their games.
As a result, I have been able to make up a bootable menu driven disk full with 28 games that all work ONLY on a Microbee 256TC. There are 2 games that didnt need any conversion, Target (Colour version) and Hopper.
I can also confirm that the copy protected Honeysoft disks of type t4 (have full colour menus), such as honeysoft_penny_arcade_t4.dsk, all work on the Microbee 256TC as well as earlier Microbee's. So none of those games are included here. The types t1, t2 & t3 only work on earlier Microbee's.
The 28 games on this disk are :-
Alien Cresta
Apple Panic
Battle Station
Centipede Attack
Cosmic Fighter
Defence Command
Galaxy Invasion
Galaxy Invasion Plus
Ghost Hunter
Hopper
Hoppy
Jungle Raiders
Killer Beetles
Meteor Mission I
Meteor Mission II
Killopede
Minedrop II
Munch
Outhouse
Penetrator
Gun Fighter
Sea Dragon
Target - Colour version
Tandy Invaders
Volcano Hunter
Asteroids Plus
Car Race
So in the Microbee/Software/Games folder we placed
256tc_arcade_games_ds80.dsk
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ChickenMan
ChickenMan