(48 odpowiedzi, napisanych Konsole)

Also to get more DMA cycles, you can set the width to 32 characters and turn off doublewide.  It makes your horizontal resolution smaller but will get you more cycles.

You can also use 320D mode.  It costs less DMA time (like 320A) but has the limitation of every odd numbered column having different colors from the even numbered ones.  You also have to turn on Kangaroo mode for it to work, but it may be possible to change the colors more reliably with interrupts.  320D has no normal practical use, but might work in this instance.


(48 odpowiedzi, napisanych Konsole)

On 320B mode ... it works like Antic 4 on XL/XE except that color 01 will only display when next to itself.  In other combinations it makes it into color 00 (background).  This can be fixed by turning on what is called Kangaroo Mode.  By setting bit 2 ($04) in CTRL register, it kills transparency and enables all colors to be used anywhere in the character.  It also kills transparency on any sprites.

On the Dragonfly SD card, find my Sky Scraper game demo.  Title screen uses an interlaced 320B where I swapped character sets every frame to make it display 9 colors plus BG per character, 20 colors counting both palettes.  To access this I had to turn on Kangaroo mode so all the colors would work.


(48 odpowiedzi, napisanych Konsole)

Hey RJ:

I am going to try these on my real HW, but thought you might want to try these too!

-0 and -1 have the POKEY's reversed, so they will play differently on single POKEY setups.  Let me know if they work!


(9 odpowiedzi, napisanych Programowanie - 8 bit)

https://atariage.com/forums/topic/31333 … 1-release/

This program lets you play with settings.  You can set AUDCTL, SKCTL, it will even generate frequency sweeps you can record on Altirra and then put into a frequency analyzing program to generate note tables.


(9 odpowiedzi, napisanych Programowanie - 8 bit)

xxl napisał/a:

jak by to mialo pomoc w wygenerowaniu fali o roznych czestotliwosciach z roznmi wypelnieniami... albo nie mowimy o tym samym albo czegos ciagle brakuje.

konkretny przyklad:

fala prostokatna dla czestotliwosci:
1. "C" z wypelnieniem 10/90
2. "C" z wypelnieniem 90/10
3. "C2" z wypelnieniem 20/80

jakie wartosci powinny wyladowac w rejestrach dla tych konkretnych przykladow?

For C1 or C2, engage AUDCTL=$03 or $05, then you will play a C1 or C2 note in both channels (0 and 2, or 1 and 3) and delay the start of second channel note, by playing zero frequency in second channel.  Because you are in 15khz mode, it may require more delay until you get the desired pulse width.


(9 odpowiedzi, napisanych Programowanie - 8 bit)

You must use hi pass filter (AUDCTL=$04 or $02) then play same frequency in both channels (0 and 2, or 1 and 3).  By playing 0 in the silent channel for a number of cycles before playing the frequency, you can change the pulse width.

Also:  AUDCTL=$10, silence second channel, play first with $Ax distortion, set frequency in second channel to $01 ... you get an octave of notes from B2 to A#3 at 25% duty cycle pulse width.  $02 and $03 on second channel lets you get lower bass notes too.


(48 odpowiedzi, napisanych Konsole)

Nice ... Crownland on the Atari 7800 maybe?


(48 odpowiedzi, napisanych Konsole)

New header is here:

https://atariage.com/forums/topic/16042 … nt=4731984


(48 odpowiedzi, napisanych Konsole)

No.  Should be at $440 ... I think it needs that new header for .a78 maybe


(48 odpowiedzi, napisanych Konsole)

Can someone try this on Dragonfly and see if it works?

It compiles correctly, but I believe the cartridge header needs to be modified.


(48 odpowiedzi, napisanych Konsole)

I should have a double POKEY demo for my Metroid tunes done by weekend, hopefully.


(48 odpowiedzi, napisanych Konsole)

Here are three .xex binaries for Metroid music using double POKEY, plus sources.

My goal, is to convert these into .a78 executables for 7800 console using Dragonfly cartridge.  Dragonfly uses double POKEY mapped to $440 and $450


(48 odpowiedzi, napisanych Konsole)

Your track uses hi pass filter.  ProSystem emulation will not play it.  The current version of A7800 emulator does this feature better though.


(48 odpowiedzi, napisanych Konsole)

Pracuję nad podwójnym demo POKEY.  Mam plik binarny dla A8 w asemblerze MADS, ale nie udało mi się go przekonwertować na 7800 DASM.

Dziś wieczorem po pracy opublikuję tutaj swoje pliki binarne.  Mam nadzieję, że ktoś może na to spojrzeć.  Na wkładzie Dragonfly POKEY jest na $440 i $450.  Może to wymagać nowego nagłówka .a78 dla podwójnego POKEY.

Przepraszam, jeśli mój polski jest zły.  Wciąż się uczę i polegam na tłumaczu.


(20 odpowiedzi, napisanych Programowanie - 8 bit)

Don't know if this will help:

In Atari BASIC you can mess with the variable name table, and set a string to point to the screen memory (88+89*256) ... doing string assignments in the normal way, like S$(1,10)="XXX" will cause the data to be instantly POKE'd to the screen.  This can be a quick way to do blitter graphics or softsprites.

The article which shows this is here: http://www.atarimagazines.com/compute/i … k_poke.php

Best news:  This is done without using assembly!

You MUST make sure the string you use is the first string declared in the program, and you cannot use this in immediate mode or the Atari will crash.

Also, if you use revision A of BASIC (400/800) you cannot DIM the string to a multiple of 256, this triggers a lockup bug.  Add one to the value.