The CoCo Five (My Idea of the Ultimate Color Computer.)


The coco 5 idea is based on the original  coco 4 idea I had in the ninety's but with the 6309 cpu's replaced by an FPGA implementation, the IR interface replaced by Bluetooth and a few other minor changes and many refinements.

Before looking at this page you may want to know what the motivation behind the idea is if so click here to view the History and Philosophy behind the CoCo5 idea.

This page just contains an overview of the MAJOR ideas behind the CoCo5 read it first.
But to fully understand the CoCo5 read everything in this READING LIST.

The main points are listed below click the description for more details or (Click here to go to the top of the details section) :
    MainPoints:
  1. The system to be housed in case almost identical to coco 3 case,
       ↓
    Click below the down arrows to view the CoCo 5 from all sides:
    ↓    
    Top View
    Top Right
    Left Side View
    Back View
    Right View
    Front View
    Front View With SuperIDE in Slot#1i
    Underside View

  2. The system includes three standard coco cartridge ports, one internal and two external.
  3. System built around four virtual 6809 compatible cpu's.
  4. System makes effective use of 8 Meg or RAM.
  5. Advanced graphics chip backwards comparable with GIMEx with Composite and VGA outputs .
  6. The TV out port is not used but available for a future interface and the RGB port is replaced by a usb  1.1 port.
  7. All other ports are the same, two additional joystick ports may be added below existing joysticks.
  8. 256K of the ram is NVRAM ant there is a 256K system ROM and a128K of user PROM.
  9. Modes for CoCo 2. 3 compatibility as well as tape and disk compatibility.

Operation

For a better understanding of why these particular features have been chosen one needs to understand how it is envisioned that this system would operate. Click here for a point summary of CoCo5 operation.
 
Optional Features and Extras

Aside from the base features described above some optional extras that I had envisioned are discussed in a separate document. Click here for a summary of CoCo5 optional extras.
 

Implementation Possibility's

As for implementation that would be for others with much more hardware understanding than I to decide but I have some high level ideas about several possible implementation methods . Click here for a discussion of the pros and cons of various of CoCo5 implementation methods.
  Appendix
Click here for a list of appendices to this document that provide more details .
 






System Details Sections

The details of the Main Points are discussed followed by Details of Operation, Optional Features and Extras, Implementation Possibility's and an the Appendix.
Each section is separated from the previous by it's title immediately followed by a single horizontal rule.



Main Points

Details: We will discuss the details of each of the main points in same order as they are listed above.

Point #1 To give the system a nice retro look and feel it will be designed on a board that will lineup with all standard coco ports. The bottom half of the case will be designed to be able to use the top  half of  a standard CoCo3 case although a CoCo5 specific top half will ba an available option.
The bottom half of the case will differ from the standard in that instead of having a .25 inch greater width at the top of the left and right sides the greater width will continue the full width the full 1 1/8 inch height of the base.
The base also differs by having a Molex or USBc power connector just below where the power wire would come in in the CoCo3.

For other differences lets take a walkabout of the CoCo5.

The Top View looks very much like a CoCo 3 except for the lable and the two extra keys on the keyboard.


The Top View might also show another difference if both external Cartrige ports are occupied.
Here we have a view with a CoCo DAC in the top slot and a CoCo SDC in the bottom.

The top external cartridge (Cart-T3) is in the same place as the standard coco 3 cartrige slot.
The bottom external cartridge (Cart-B2) is imediately below the coco 3 cartrige slot requireing the special case bottom.


The left side view features a removable aproximately one inch square grate that may be replaced with a port mounting interface or be left as is for internal speakers, cooling fans or passive cooling.

The back view which in this case includes the side on view of two cartridges from left to right has the following items on the top case as seen from the back, And on the bottom case from left to right has the following as seen from the back,


This Right Side View shows a CoCo 5's two external Cartrige Slots and the "Ventalation" slot.
Note the CoCo 5 is exactly the same height as the Color Computer 3.


This Front View shows the CoCo 5's Internal Cartridge access port.


This Front View shows the CoCo 5's Internal Cartridge access port open allowing access to the CF card of a SuperIDE Interface Cartrige.
The front access port works well for Cloud 9's SuperIDE, DISTO's Super Controler* Mini Bus Expansion.
(* of course an internal floppy drive would not be of much use although I can imagine some case hacks that would fix that.)

The Underside View is quite similar to a color computer 3 except:
  • The RGB out port has been replaced by a USB 1.1 port.
  • The cable run raceway follows a different route to a different exit on the back.
  • The Pocket Port is gone.
  • The Serial Numbers start at 5 000 001.





  • Point #2 The three standard cartridge ports compatible with all coco disk cartridges and remapable into various configurations if the CoCo 5 is in Managed Hardware Mode.

    Point #3. The CPU's unlike those specified by Sock Master will each have a distinct role. These CPU's are designated #0 to #3.
    C.P.U.
    Designation
    MMU Memory Access Modes

    Functional Modes
    Comments

    Standard
    Extended
    Tri-CoCo
    Dual-CoCo
    #0
    2048K
    :maped: 8x8K
    8192K
    :maped: 4x8K+1x32K
    Executive System Controler Executive System Controler +
    Limited Hardware Shareing
    As Executive System Controler this CPU allways runs at full 8x speed which is 7.14 MHz. and primarly deals with the keyboard and video it also provides some API shareing functions to the other CPU's.
    #1
    2048K
    :maped: 8x8K
    4096K
    :maped: 4x8K+2x16K
    CoCo BLUE
    Hardware Allotment
    Manager.
    In Dual-CoCo mode this CPU acts as Hardware Allotment Manager and is used to setup hardware ownerships and shareing between CoCo_Green & CoCo_RED.
    In Tri Coco mode it acts as a the 512K CoCo_BLUE and hardware allotment is fixed and shareing limited.
    In either mode speed is 1x ..to.. 8x where x=0.894885(the coco2's speed) which makes the max speed 7.159 MHz.
    #2
    2048K
    :maped: 8x8K
    N/A
    CoCo Green

    The Virtual CoCo_Green is set as a 64K coco2  or a 256K coco3 based on NVR Settings in Tri-CoCo mode and can be setup flexibally as a CoCo 2 or 3+ in Dual-CoCo mode.
    #3
    2048K
    :maped: 8x8K
    N/A
    CoCo RED

    The Virtual CoCo_RED is set as a 2 Meg. CoCo3+ in Tri-CoCo mode and can be setup flexibally Dual-CoCo mode.

    CLICK to CHOOSE: Return to List or More Details.
    Each CPU's function will be described in more detail later but what follows is a short summary.

    Point #4. The effective use of RAM.
    RAM use is at the core of this design and is best described with reference to RAM layout "Image Map". The main points are The overall memory organization is described by the 8 Meg. Memory Map below each small block in the map is 8 killobytes (ie. the smallest area that can be mapped into the 6x09's 64K address space).
    To get more details about how the CoCo5 uses each area of memory just click on that area of RAM Memory Map.


    I/O Buffers virtual Tape Iigh Def. Video Memory volatile Un-Disk non-volatile Un-Disk non-volatile Quarter-Disk Settings Home Memory for CPU #2 Shared Memory for CPU's 3  and 2 Home Memory for CPU #3 Shared  Memory for CPU's 2 and 1 Shared Memory for All CPU's Shared Memory for CPU's 3 and 0 Home   Memory for CPU;s 2 and 1 Shared Memory for CPU;s 1 and 0 Home Memory for  CPU #0 CoCo 5 Memory Map


    Point #5. The Advanced graphics chip backwards compatible with GIMEx .
    This  GPU has the following features.
    For an in depth discussion of the GIMMEx32 click here.
    Point #6. The TV out port is not used but available for a future interface and the RGB port is replaced by a usb 1.1 port..
    The usb 1.1 port has three functions:
    1. Used to install update files for FPGA and ROM from a PC.
    2. Used with three button scroll mouse for the advanced function interfaces.
    3. Used with a mouse to replace the missing Fn and Tandy keys if only a standard coco 3 keyboard is being used.


    Part of the space where the TV out interface had been located on a coco 3 is replaced by a hatch for future interfaces.
    ( The picture in the "walk arround" shows the hatch removed but no card installed. )

    Some possible interface cards couls be:
    1. A Composite IN port for video digitizing.
    2. A RGB port for use with an RGB monitor.
    3. A DVI port for modern Video Output.

    Point #7. All other ports are the same, and additional joystick ports may be added below existing joysticks..
    The two options for additional joystick ports are:
    • Two Coco Joystick compatible mini-DIN 6 ports or
    • An Atari Joystick compatible DB-9 or a DB-15 designed to split into two Atari Joystick interfaces.
    Click here for a visual summary of the available ports on the back of the CoCo.
    Point #8. 256K of the ram is NVRAM ant there is a 256K system ROM and a 128K of user EEPROM.

    Actual implementation of this need not be NVRAM,ROM,EEPROM as origionally envisioned but in whateve makes the most sense in the 2020's.

    These blocks have the following functions:
    Point #9. Modes for CoCo 2. 3 compatibility as well as tape and disk compatibility.
    Return


    Operation
    Return


    Optional Features and Extras
    Return


    Possible Implementation Ideas
    Return


    Appendix
    Return