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Sep 21, 2005 · I've always thought that the three biggest mistakes that Atari/GCC made in designing the 7800 were: installing RF-modulated audio/video output (it should have been composite right from the start), leaving out the sound upgrade (it was part of the original specifications for the console but was later cut out), and designing sub-par controllers (the dual fire-button upgrade was a clever bit of ...
- Introduction
- Overview of The 7800
- Overview of Maria
- Overview of Tia
- Overview of 6532
- Inptctrl Register
- Appendix 1: 7800 Memory Map
- Appendix 3: DMA Timing
The 7800 is a product which combines the ATARI 2600 hardware with a new graphics chip called MARIA. The entire 2600 library of cartridges will run on the 7800 as they do on the 2600, but new cartridges designed to access the improved hardware will be able to take advantage of a large number of improvements.
Ignoring the 2600 environment, which is identical to the ATARI 2600, the 7800 environment is characterized by the following: 1. (2) 6116's 1.1. 4K bytes of RAM 2. 6532 2.1. I/O 3. TIA 3.1. sounds 3.2. some input ports. 4. Expanded cartridge slot 5. SALLY (6502) 5.1. microprocessor running at 1.79 MHz. 6. MARIA 6.1. all video Additionally, there is ...
Graphics
MARIA does not employ the concepts of players, missiles, and playfield, as do the 2600 and 5200. Instead MARIA uses an approach to graphics commonly used in coin-operated games. Each raster of the display may be thought of as a bit map. This map is contained in an area of the MARIA chip called the Line RAM. Information is first stored into the Line RAM, then later read from Line RAM and displayed on the screen. Consider for a moment just one raster of display. One would compose this raster's...
Display
For NTSC consoles, there are a total of 263 rasters per frame (~1/60th second). The "visible" screen (during which MARIA attempts display) starts on raster 16 and ends on raster 258. The area found visible on all television sets starts on raster 41 and ends on raster 233, 192 scan lines later. Any display outside this area may not appear on all televisions. See Appendix 4, Frame Timing, for more details. For PAL consoles, there are a total of 313 rasters per frame. (~1/50th per second). The “...
Sound
In TIA there are two audio circuits for generating sound. They are identical but completely independent and can be operated simultaneously to produce sound effects through the TV speaker. Each audio circuit has three registers that control a noise-tone generator (what kind of sound), a frequency selection (high or low pitch of the sound), and a volume control.
The I/O Ports
The two ports (Port A and Port B) are 8 bits wide and can be set for either input or output. Port A is used to interface to various hand-held controllers but Port B is dedicated to reading the status of the console switches and joystick buttons.
The INPTCTRL register is responsible for switching and locking the 7800 into either 2600 or 7800 mode. It's a write-only register mapped to $0000-$001F, and controlled by external circuitry.INPTCTRL's address range overlaps TIA's address range. As a consequence, once this register is set you need to also set the lock bit (see below) before you can ...
The memory map of the 7800, graphically illustrated on the next page, is in many ways similar to that of the 2600, with the addition not only of MARIA, but also of 4K of RAM. This RAM is shadowed (responds to other addresses) in zero, first, second, and third pages, the first two of these being significant. You will notice the absence of the 128 by...
There is some uncertainty as to the number of cycles DMA will require, because the internal MARIA chip timing resolution is 7.16 MHz, while the 6502 runs at either 1.79 MHz or 1.19MHz. As a result, it is not known how many extra cycles will be needed in DMA startup/shutdown to make the 6502 happy. It is even possible for the 6502 to be in the middl...
7800 SOFTWARE GUIDE INTRODUCTION The 7800 is a product which combines the ATARI 2600 hardware with a new graphics chip called MARIA. The entire 2600 library of cartridges will run on the 7800 as they do on the 2600, but new cartridges designed to access the improved hardware will be able to take advantage of a large number of improvements.
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Feb 25, 2024 · It’s not to say the 7800 couldn’t produce decent modern software. Atari would release very good ports of the arcade titles Crossbow, Xenophobe, Commando, and Ikari Warriors. Activision (one of the few 3rd party companies that supported the 7800) made a nice port of Bally-Midway’s Rampage.
To enable them for your game, use the changecontrol command in your program code, specifying controller port 0 or port 1. changecontrol 0 stmouse changecontrol 0 amigamouse 7800basic will then read the selected mouse every frame, and adjust the mousex0 and mousey0 variables (controller port 0) or mousex1 and mousey1 variables (controller port 1).
Sep 23, 2020 · I have Retroarch working really well with Atari 2600 but would like to play Atari 7800 games as well. I want to set up binds just for that core. I've done a bit of Googling and reading and was under the impression I could do the following: Load the core (in this case Prosystem) Go to Quick Menu > Controls > Port 1 Controls
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What's new on the Atari 7800?
Can Atari 2600 paddle controls be used with 7800basic?
Does the Atari 7800 have a sound chip?
Does the Atari 7800 have a joystick?
What controls are on a 7800 console?
Will a 2600 run on a 7800?
The Atari 7800 ProSystem, or simply the Atari 7800, is a home video game console officially released by Atari Corporation in 1986 as the successor to both the Atari 2600 and Atari 5200. [3] It can run almost all Atari 2600 cartridges, making it one of the first consoles with backward compatibility .
