Re: 4040

From: William Levak (wlevak_at_cyberspace.org)
Date: 2000-12-31 07:38:37

On Fri, 1 Dec 2000, John Phipps wrote:

> Ruud,
> 
> Out of curiousity, do you know what the memory map is for the 6530 in the
> 4040 drive? I guess there's no difference between DOS 1 or DOS 2 devices (or
> is there?)

This is the memory map of the 4040 as far as I have it.  It does not
contain information on the unassigned regions below 1K for the 6504
processor.  These are dependent on the exact programming of the address
decoding in the 6530.  I cannot say for sure that this layout is the same
for all versions of the 2040/3040/4040 6530's, but I see no reason why
they would be different.  I may be able to read the entire memory space of
the 6504 side of the 4040.  This would require modifying one of my
existing programs, so it will be a while before I know for sure if I
can do it.  I have only one version of the 6530 for this drive.  There are
three that I know of.  


                   4040 Memory Map
         6502                                6504

 0000-007F  6532 #1 RAM            6530 RAM     0000-003F
 0080-00FF  6532 #2 RAM            
 0100-01FF  shadows(0000-00FF)     
 0200-001F  6532 #1 I/O            6522         0040-004F
 0220-027F  shadows(0200-021F)     
*0280-029F  6532 #2 I/O            6530 I/O     0080-008F
 02A0-02FF  shadows(0280-029F)
 0300-03FF  shadows(0200-02FF)
 0400-0FFF  shadows(0000-03FF)
 1000-13FF  -------------- common RAM --------  0400-07FF
 1400-1FFF  shadows(1000-13FF)
 2000-23FF  -------------- common RAM --------  0800-0BFF
 2400-2FFF  shadows(2000-23FF)
 3000-33FF  -------------- common RAM --------  0C00-0FFF
 3400-3FFF  shadows(3000-33FF)
 4000-43FF  -------------- common RAM --------  1000-13FF
 4400-4FFF  shadows(4000-43FF)
 5000-7FFF  shadows(D000-FFFF)     unconnected  1400-1BFF
 8000 CFFF  shadows(0000-4FFF)
 D000-DFFF  ROM
 E000-EFFF  ROM
 F000-FFFF  ROM                    6530 ROM     1C00-1FFF

* Reading or writing the 6532 timer after address 028F
  alters interrupt settings and may hang the system.


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