MuAmi Amiga Propeller fusion (ECS).

davidsaunders

Ok an overview.

The 68K series of cpus make it simple to have an external MMU, taking advantage of this and using one Prop as that MMU, this Prop is also used as the Super Agnus. The Super Agnus Prop uses a 12-bit bus (8-bit data/address, 2 bit device select, and 2 bit function select) to communicate with the remaining Props.

The Paula is a very simple device consisting of a single Propeller, this Prop is also used to help the Super Agnus manage the data portion of the bus.

Now the big one:
Two props and some SRAM are used to implement a video system that is compatible with the Super Denise, though includes some neat new functions. When the area of RAM currently allocated to video is written, this data is mirrored over the Prop2Prop bus to the video Props to be mirrored in video ram.

Baggers

davidsaunders wrote: »

Since it seems that there are many questions in various other threads about the architecture of the MuAmi as it relates to the use of the Propeller for the implementation of the AGA chipset, I am starting this thread to address these issues. This will also help me to document the MuAmi better (as any one that has looked at my site can attest the documentation is lacking). After all at this time the creation of the MuAmi is my 'Day Job'.

I WILL UPDATE THIS TOP POST TO BETTER REFLECT ALL INFORMATION PROVIDED IN THIS THREAD, AS IT COMES.

To get started, here is a basic overview of the function of the MuAmi.

1) A 32-bit Data and Address bus 680x0 is at the core of the design, the memory map below the 16MB mark is pretty much identical to the Amiga 1200/4000, with the HW registers located from $00DF0000 to $00DFFFFF, though the space that is normally reserved for the Zorro bus is used for additional chip mem. The space from the 16MB mark to the 2 GB mark is used for FastMem, and everything above that for custom expansions. Using the Amiga OSes great memory handling it is possible to have much more than 2GB of ram by way of page switching (currently I am playing with seeing how it does with 16GB), though this does require the installation of a simple Amiga OS patch.

2) there is a Propeller that is responsible for reading the HW registers, and Chip Mem, that sends the data to other Props, by way of the Prop2Prop bus, to perform other tasks. This Prop is also responsible for simulating the Copper and part of the Blitter (because access to full chip mem is needed), as well as controlling the KB and mouse.

3) Yet another Prop is responsible for coordinating the Props used in the chipset, and doing some processing related to the chipset.

4) There is a Prop on the Prop2Prop bus that handles nothing but audio and joystick related stuff.

5) Two props are used to simulate an extended version of the AGA video HW, by using SRAM to directly drive a resistor DAC. They update the screen buffer (in there private SRAM) from data sent them by way of the Prop2Prop bus from chip mem.

There will be more to add as this thread evolves. I also will be attaching the occasional Block diagram to this top post as needed.

For more Amiga specific information please see:
http://cataclysm.cx/random/amiga/reference/Hardware_Manual_guide/node0000.html
and
http://www.mways.co.uk/amiga/howtocode/
More to come.

Cool, thanks for the update do you have pin layouts for the props?
I take it that the prop that handles the audio has access to the ram too?

Leon

There is also the AmigaOne X1000, which uses PowerPC and XMOS chips:

http://www.a-eon.com/x1000.html

Leon

The 68000 is easy to program in assembler, but modern devices like the PowerPC are designed to be programmed in C.

Baggers

davidsaunders wrote: »

If only I had a second monitor I have realized that I could use the camera on my PC, so it may be better to look for a cheep working monitor. As it is rather difficult to record something with out being able to see what you are recording.

Updated top post to ask for aid in explaining things.

Baggers:
I thank you very much. I have been neglecting the documentation on the MuAmi because of not being able to explain things very well. As such I welcome any help in explaining things.

No worries glad to ask, like I said earlier, this is one of my interests, retro computers, and screen display generators using the prop being top of my list.
Which is why I was wondering how you were going to get the throughput with only 8bits. as most of the drivers that use external ram have fill rate issues, finding ways to write whilst reading to display the screen.
I guess because of my work in these areas I'm also intrigued by others work, and methods of doing things.

Leon

The PowerPC has a Link register and instructions that make things easy for compilers.

Ahle2

I'm running my Amiga 1200 in 1024x768 using the AGA chipset. (no graphics card connected)
Even tough an AGA Amiga can output a standard VGA signal (640x480), I'm using an Indivision AGA to convert the interlaced 1024x768 signal to a "PC friendly" signal.

Even the Amiga 1000 with the OCS chipset could handle graphics modes up to 768x576 (PAL, highres interlaced, full overscan).
(Wow, the Amiga 1000 was soooooo advanced for 1985)

Ahle2

Do you mean drive a SVGA monitor directly at 1024x768 without a flicker fixer?

The Amiga graphics hardware is the most flexible I have ever seen.
With copper tricks you could achieve magic; Like "mode 7" graphics as seen in sanity demos and in games such as "Brian the lion" and "Mr nutz".
And all that on hardware from 1985.

Ahle2

http://www.youtube.com/watch?v=rlEkR1eB3z8
Looking forward to the final movie!

davidsaunders

As soon as I have all the pinouts for the Propellers in MuAmi, in pngs I will post them here.

davidsaunders

If this appears a bit fragmented at this time, I am redoing the top post, and I have removed my intermediate comments, so that all the information should end up being more accessible.