[Coco] Re: 64K Mode
jdaggett at gate.net
jdaggett at gate.net
Wed Jan 14 13:19:42 EST 2004
John
Never bought that book. Maybe one day if I can find a copy I might
buy it.
james
On 14 Jan 2004 at 13:08, John Collyer wrote:
From: "John Collyer"
<johncollyer at zoominternet.net>
To: "CoCoList for Color Computer Enthusiasts"
<coco at maltedmedia.com>
Subject: Re: [Coco] Re: 64K Mode
Date sent: Wed, 14 Jan 2004 13:08:24 -0500
Send reply to: CoCoList for Color Computer Enthusiasts
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> It's documented.
> See Tepco's (ASSEMBLY LANGUAGE PROGRAMMING For The TRS-80 COLOR
> COMPUTER) book.
>
> John Collyer
>
> ----- Original Message -----
> From: <jdaggett at gate.net>
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Sent: Wednesday, January 14, 2004 1:06 PM Subject: Re: [Coco] Re: 64K
> Mode
>
>
> > John
> >
> > Then that is a undocumented. Accoording to the Service Manual the R0
> > and P registers are not documented. Leaving one to believe that
> > those SAM features are not supported.
> >
> > james
> >
> >
> > On 14 Jan 2004 at 12:52, John Collyer wrote:
> >
> > From: "John Collyer"
> > <johncollyer at zoominternet.net>
> > To: "CoCoList for Color Computer Enthusiasts"
> > <coco at maltedmedia.com>
> > Subject: Re: [Coco] Re: 64K Mode
> > Date sent: Wed, 14 Jan 2004 12:52:57 -0500
> > Send reply to: CoCoList for Color Computer Enthusiasts
> > <coco at maltedmedia.com>
> > <mailto:coco-
> > request at maltedmedia.com?subject=unsubscribe>
> > <mailto:coco-
> > request at maltedmedia.com?subject=subscribe>
> >
> > > That's true, but it also works on a coco3. Try it.
> > > Run SuperPatch EDTASM+ on a coco3 emulator
> > > and see if it don't work. I'll bet it does.
> > >
> > > John Collyer
> > >
> > > ----- Original Message -----
> > > From: <jdaggett at gate.net>
> > > To: "CoCoList for Color Computer Enthusiasts"
> > > <coco at maltedmedia.com> Sent: Wednesday, January 14, 2004 12:57 PM
> > > Subject: Re: [Coco] Re: 64K Mode
> > >
> > >
> > > > John
> > > >
> > > > That is what I have been saying. This is for the SAM CHIP ONLY
> > > > COCO 1 and 2 Only
> > > >
> > > > In Memeory Map type 0 (ZERO)
> > > >
> > > > Ram is in the lower 32K and ROM and vectors in the upper 32K.
> > > > With 64K of ram on board, the Ram is configured as two (2)
> > > > banks of 32K mapped in the lower 32K of the memory map. The "P"
> > > > register controls which page is mapped in.
> > > >
> > > > In Memeory Map Type 1 (ONE)
> > > >
> > > > Ram is configured from address $0000 to $FEFF. The upper 256
> > > > bytes are not accessable as they are I/O and vector sapce.
> > > >
> > > > james
> > > >
> > > >
> > > >
> > > > On 14 Jan 2004 at 10:49, John Collyer wrote:
> > > >
> > > > From: "John Collyer"
> > > > <johncollyer at zoominternet.net>
> > > > To: "CoCoList for Color Computer Enthusiasts"
> > > > <coco at maltedmedia.com>
> > > > Subject: Re: [Coco] Re: 64K Mode
> > > > Date sent: Wed, 14 Jan 2004 10:49:25 -0500
> > > > Send reply to: CoCoList for Color Computer Enthusiasts
> > > > <coco at maltedmedia.com>
> > > > <mailto:coco-
> > > > request at maltedmedia.com?subject=unsubscribe>
> > > > <mailto:coco-
> > > > request at maltedmedia.com?subject=subscribe>
> > > >
> > > > > OK, Everyone lets get this correct. Here are the details:
> > > > >
> > > > > The page number bit, P1 is cleared by BASIC when the computer
> > > > > is turned on. The effect of P1 set can only be used by a 64K
> > > > > CoCo. A 64K RAM is considered as two 32K pages. When the page
> > > > > number bit is clear page 0 is the first 32K and page 1 is the
> > > > > upper 32K. With TY clear (ROM/RAM mode) and the page number
> > > > > bit clear the first 32K RAM occupies addresses $0000 through
> > > > > $7FFF and ROM extends upward from there. Setting the page
> > > > > number bit results in the upper 32K of RAM, which was not
> > > > > accessible with TY clear, being accessed by addresses $0000
> > > > > through $7FFF. This allows you to have two BASIC programs in
> > > > > RAM at the same time. One in Page 0 and the other in page 1.
> > > > >
> > > > > TY | Memory map mode | Set | Clear
> > > > > $FFDF | $FFDE
> > > > >
> > > > > P1 | Page Number | Set | Clear
> > > > > $FFD5 $FFD4
> > > > >
> > > > > This is how it really works!
> > > > >
> > > > > John Collyer
> > > > >
> > > > >
> > > > >
> > > > > ----- Original Message -----
> > > > > From: <jdaggett at gate.net>
> > > > > To: "CoCoList for Color Computer Enthusiasts"
> > > > > <coco at maltedmedia.com> Sent: Tuesday, January 13, 2004 11:35
> > > > > PM Subject: Re: [Coco] Re: 64K Mode
> > > > >
> > > > >
> > > > > >
> > > > > > What ever.
> > > > > >
> > > > > > Correct I shorted the upper range 16 bytes. $FFF0 is the
> > > > > > start of I/O. The Ram is switched in two banks and are
> > > > > > located between $0000 and $7FFF when memory map type 0 is
> > > > > > selected.
> > > > > >
> > > > > > The HD63x09 has vector for illegal opcode trap at $FFF0 and
> > > > > > $FFF1. The MC68x09 does not.
> > > > > >
> > > > > > james
> > > > > >
> > > > > > On 13 Jan 2004 at 18:04, Alex wrote:
> > > > > >
> > > > > > From: Theodore (Alex) Evans
> > > > > > <alxevans at concentric.net>
> > > > > > Subject: Re: [Coco] Re: 64K Mode
> > > > > > Date sent: Tue, 13 Jan 2004 18:04:41 -1000
> > > > > > To: CoCoList for Color Computer Enthusiasts
> > > > > > <coco at maltedmedia.com> Send reply to: CoCoList for Color
> > > > > > Computer Enthusiasts <coco at maltedmedia.com> <mailto:coco-
> > > > > > request at maltedmedia.com?subject=unsubscribe> <mailto:coco-
> > > > > > request at maltedmedia.com?subject=subscribe>
> > > > > >
> > > > > > > On Jan 13, 2004, at 3:39 PM, jdaggett at gate.net wrote:
> > > > > > >
> > > > > > > > The Sam Chip in the Sam Chip of the CoCo 1/2 hasa two
> > > > > > > > memeory map types
> > > > > > > >
> > > > > > > > Type 0 is ram from $0000 to $7FFF and Rom from $8000 to
> > > > > > > > $FDFF and from $FFF2 to $FFFF. $FF00 to $FFDF is I/O
> > > > > > > > and $FFE0 to $FFF1 unused.
> > > > > > > >
> > > > > > > > Type 1 is all ram $0000 to $FDFF. $FF00 to $FFDF is I/O
> > > > > > > > and $FFE0 to $FFF1 unused. $FFF2 to $FFFF is ROM and
> > > > > > > > vector location.
> > > > > > >
> > > > > > > I am almost positive that the the area switched extends up
> > > > > > > to $FEFF with only 256 bytes for I/O and vectors. In fact
> > > > > > > according to some notes that I made a long time ago the
> > > > > > > destinations for the all but one of the 6809 vectors (I
> > > > > > > don't have a note for the 6309 unimplemented instruction
> > > > > > > at $FFF0) lie in in the FE00-$FEFF range. SWI3 pointing
> > > > > > > to $FEEE, SWI2 to $FEF1, FIRQ to $FEF4, IRQ to $FEF7, SWI1
> > > > > > > to $FEFA, and NMI to $FEFD with reset being the exception
> > > > > > > which points to $8C1B
> > > > > > >
> > > > > > >
> > > > > > > --
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