CPU #0
The CoCo 5 was imagined to
be controlled by 4 - 6309 CPU's and a GPU , If it ever gets implemented it
will most likely be via FPGA. The CPU#0 refers to a 6309 or Turbo9 core
which will provide an executive supervisory function for the entire
system.
This CPU will always run at
7.152 MHz and will address memory beyond 64K by one of two methods STANDARD
or XSC mode.
- STANDARD mode uses 8 banks of 8K to access up to 2 MB of memory
just as a CoCo 3 would.
- XSC
eXecutive Supervisory Controler mode
uses 4 banks of 8K and one 32K bank to access up to8MB of memory, the 8K
banks are mapped to below 32K and the 32K bank above.
The main functions of CPU#0
are to:
- Handle System Startup including initialization of CPU's #1,2 and 3
based on physical switches, NVRAM settings and initial hardware
configuration.
- Handle all Keyboard Input allowing for keyboard buffering even
when the destination CPU is halted and allow for Macros.
- Work with the GPU to handle all Screen Output.
- Handle hardware systems for Tri-CoCo Mode.
To