Search found 35 matches

by Fabrizio Caruso
Fri Oct 04, 2019 8:03 am
Forum: Games programming
Topic: [cc65]How can I redefine characters and use colors?
Replies: 10
Views: 9480

Re: [cc65]How can I redefine characters and use colors?

Sorry guys, @carlsoon, I don't understand what the screen active bit is and how the VDP registers are accessed in your code LDA #$E2 ;new value including set screen active bit STA VDP_Status_Write LDA #$81 ;write into register 1 STA VDP_Status_Write ;see comments on that BIOS routine above Which is ...
by Fabrizio Caruso
Thu Mar 15, 2018 2:44 pm
Forum: Homebrew software and hardware (excluding games)
Topic: [SOLVED][VDP] What are the two bytes that have to be written into the VDP status address?
Replies: 4
Views: 4926

Re: [VDP] What are the two bytes that have to be written into the VDP status address?

Sorry I still do not understand why on other examples I see $80 added instead of $40. I need some simple to write into VDP memory from C without using interrupts. I am supposed to do this in C with very little Assembly. Let us assume the VDP registers are already set. I need: 1. a function VPOKE(loc...
by Fabrizio Caruso
Thu Mar 15, 2018 10:45 am
Forum: Games programming
Topic: [cc65]How can I redefine characters and use colors?
Replies: 10
Views: 9480

Re: [cc65]How can I redefine characters and use colors?

Thanks Carlsson, My project is written in ANSI C with almost no Assembly for obvious reasons (it is a universal 8-bit game and framework for about 100 different 8-bit systems with any 8-bit CPU, i.e., Motorola 6809, Z80, 6502 and their clones/variants) Moreover I am not fluent in any Assembly. For t...
by Fabrizio Caruso
Wed Mar 14, 2018 1:11 pm
Forum: Games programming
Topic: [cc65]How can I redefine characters and use colors?
Replies: 10
Views: 9480

Re: [cc65]How can I redefine characters and use colors?

@carlsson, in a previous reply you said I should add #$40 and not #$80 to write.

I would have expected
LDA #$E2 ;new value including set screen active bit
STA VDP_Status_Write
LDA #$41 ;write into register 1
...
instead of
LDA #$81 ;write into register 1
by Fabrizio Caruso
Wed Mar 14, 2018 11:23 am
Forum: Games programming
Topic: [cc65]How can I redefine characters and use colors?
Replies: 10
Views: 9480

Re: [cc65]How can I redefine characters and use colors?

Thanks Carlsson, I am coding in ANSI C and using nearly no Assembly. I am not sure I understand your post. I can guess that: LDA #$E2 ;new value including set screen active bit STA VDP_Status_Write LDA #$81 ;write into register 1 STA VDP_Status_Write ;see comments on that BIOS routine above Is writi...
by Fabrizio Caruso
Sun Feb 11, 2018 5:46 pm
Forum: Homebrew software and hardware (excluding games)
Topic: [SOLVED][VDP] What are the two bytes that have to be written into the VDP status address?
Replies: 4
Views: 4926

[SOLVED][VDP] What are the two bytes that have to be written into the VDP status address?

Hi

I need to access the VDP. I have understood the basics of the read/write procedure but not the details.

What do I need to write into the status read/write registers?
The first byte is the LSB.
The second byte seems to be the MSB + something else.
What is the something else?

Fabrizio
by Fabrizio Caruso
Sat Feb 10, 2018 5:20 pm
Forum: Games programming
Topic: [cc65]How can I redefine characters and use colors?
Replies: 10
Views: 9480

[cc65]How can I redefine characters and use colors?

Hi! I have manage to get my universal game CROSS CHASE to use a 16k rom. The game is using very crude graphics as provided by conio.h in CC65 for the Creativision, i.e., standard white characters on a black background in 32x24 text mode. I would like to make it more colorful. If the video chip works...
by Fabrizio Caruso
Sat Feb 10, 2018 5:04 pm
Forum: Homebrew software and hardware (excluding games)
Topic: Creativsion support added to cc65
Replies: 12
Views: 9556

Re: Creativsion support added to cc65

Hi! I have solved the problem and my game now uses 16k! The solution was given me by Madrigal! I has to swap the 8k banks. CROSS CHASE runs under MAME with no problem. I have also managed to get it to work under FunnyMu but could not use the UI. CreativMu will shortly show a black window and then qu...
by Fabrizio Caruso
Fri Feb 09, 2018 1:52 pm
Forum: Homebrew software and hardware (excluding games)
Topic: Creativsion support added to cc65
Replies: 12
Views: 9556

Re: Creativsion support added to cc65

I have two questions? Can the code "flow" from one bank to the other? or you need an explict JMP/JSR to move to the other bank? Taking whatever CC65 produces when set to build a 16k rom in $8000-$BFFF, and reversing the 8k banks, could produce something functional,i.e., something that can be run in ...