Caple C871i Manual de usuario descargar pdf (Pagina 9)

Apple II Computer Info

#############################################################################

### FILE : a2memory

#############################################################################

### Created : Tuesday, January 1, 1980 Modified: Thursday, March 1, 1973

### File Type: "TEXT" File Creator: "LMAN"

### File Size: 6266 bytes 6 KB

#############################################################################

Darkcode1 <[email protected]> wrote:

> I have an enhanced apple ][e with 128k ram and after reading through some

> old nibble magazines of mine, i stumbled across this confusing bit of

> information:

> It seems in the apple ][e, memory from $d000-$dfff has two banks where as

> memory from $e000-$ffff has only one, but what happens when there is a

> memory card installed?

If you have a 128K Apple IIe, there are actually five banks of memory in

the $D000-$DFFF area:

- ROM

- Main memory language card bank 1

- Main memory language card bank 2

- Auxiliary memory language card bank 1

- Auxiliary memory language card bank 2

There are three banks in the $E000-$FFFF area: ROM, main language card

and auxiliary language card.

The auxiliary memory in the IIe (64K memory expansion card) mirrors the

main memory for the most part. You have 48KB of RAM from $0000-$BFFF

and a further 16KB in $D000-$FFFF, with two 4KB banks in $D000-$DFFF.

There are three main sets of soft switches which deal with auxiliary

memory:

- RDMAIN/RDAUX and WRMAIN/WRAUX select main or auxiliary memory for

reading or writing the $0200-$BFFF area (independent control of read and

write bank select).

- MAINZP/AUXZP selects main or auxiliary memory for the $0000-$01FF and

$D000-$FFFF areas (one switch affecting both read and write bank

select).

The traditional language card switches ($C080-$C083 and $C088-$C08B) are

independent of the main/aux bank select. You can read from ROM or RAM,

and optionally write enable the RAM. Any access to RAM will refer to

main or auxiliary RAM according to the MAINZP/AUXZP switch.

- The 80STORE switch determines whether the PAGE1/PAGE2 switch is used

to select a displayed video page or whether it is used to bank switch

text page 1 ($0400-$07FF) between main and auxiliary memory. The AN3

(annunciator 3) switch also plays a role here, determining whether

80STORE also affects hi-res page 1 ($2000-$3FFF). I think that the

HIRES switch must also be enabled for this, but I'd have to refer to

documentation to confirm this.

Apple II Computer Technical Information : Apple II Family Hardware Info

ftp://ground.ecn.uiowa.edu/2/apple2/miscinfo/hardware : May 2001 : 9 of 572

1 2 3 4 5 6 7 8 9 10 11 12 13 14 ... 571 572

Caple C871i Manual de usuario Pagina 9

Comentarios a estos manuales

Caple C871i Manual de usuario Pagina 9

Comentarios a estos manuales

Relacionado con productos y manuales para Placas Caple C871i