System Improbable

[Bill B]

Martin set a challenge

<mission impossible theme>
Your task should you choose to accept it, design one hypothetical system using as much from the box as possible
</mission impossible theme>

Note the important word hypothetical, Here is my outline, details are left to the reader:

• It has to be a twin Z80 system. I would propose using one as the main CPU, and the other as a Graphics Processing Unit (GPU).

• Connected to the GPU Z80:
  • Two of the DRAM chips and an EPROM for data and program.
  • The VDP, and that would use the remaining DRAM.
  • One of the Atmel 40pin Micros would provide FIFO communications between the two processors.
  • One of the peripheral interface chips driving an LCD for debug/diagnostics.

• The remainder would attach to the main Z80 CPU.
  • The other Atmel 40pin interfacing with the FLASH memory to act as a storage device.
  • The second peripheral interface chip providing PATA interface for the compact flash (or a hard disk). Either connected to the Atmel or directly to the Z80.
  • FPU on the main system (or would the GPU need it more?)
  • Atmel 20pin running the two sound generators (for stereo sound).
  • The KIO chip would provide:
    • Serial Input / Output via the MAX232.
    • PS/2 keyboard input.
    • Clocks for the serial I/O and Timing for the Z80
    • PIO for printer port
  • The real time clock.
  • EPROM & static RAM for memory

• The PLDs to glue everything together.

I think that covers most of the chips Lez supplied.

[Martin A]

Can we call that the MTX++ ??

The 89C55 based Tube(C) that's intriguing, I wonder how difficult that would be in practice, it's got enough ram on board to do all of the registers the original Tube chip had. And probably enough I/O too.

Hmmmmmm I need to look at that!

[JonB]

Could we build an add-on co processor card for the MTX that gave a high resolution display? Then I could connect three monitors to it (one for the existing VDP, one for the 80 column output of the Rememorizer and a third for the new card)?

Then I could have some fun writing a set of memory mapped graphics primitives in Z-80..

[1024MAK]

Could we build an add-on co processor card for the MTX that gave a high resolution display? Then I could connect three monitors to it (one for the existing VDP, one for the 80 column output of the Rememorizer and a third for the new card)?

Then I could have some fun writing a set of memory mapped graphics primitives in Z-80..

How do you fancy writing a Z80 based screen driver? By this, I mean a 20MHz Z80 CPU "graphics slave processor" with only a little help from the hardware (just three parallel to serial shift registers and vertical and horizontal sync oscillators, no VDP/graphics chip) generates a "high resolution" eight colour bit mapped RGB display. A super ZX81 type of system.

The Z80 CPU would only be responsible for the display, nothing more. It would have to time the data transfer from the "display file" in RAM to the three shift registers fast enough so that the correctly timed data could be used to directly feed a RGB SCART TV or RGB monitor. If this works, we could then optimise it and do a VGA picture on a VGA monitor...

Mark

[lezanderson]

Perhaps some people are getting carried away with their designs !.....Best to keep things simple chaps

And remember : The hombrew Computer:

The Ten Commandments :

1 Though shall keep your design simple
2 Use easily sourced components
3 Use affordable ICs
4 Use standard connectors
5 Use standard protocols
6 Use a double sided board if possible but not essential
7 Don't make the board too small or too large keep thing in proportion
8 Test ..re-test and test again too show it works !
9 Make the schematics/PCB/Software open-source
10 Avoid using too many TTL/CMOS discrete ICs

[inaki]

Hi Lez.
Can we replace or add some component ?