Re: Auxilary Ram card programming info..

[Matt Jenkins <mdj@pacific.net.au>]

Phoenyx wrote:
> 
> Hi Matt,
> 
> What I have is reference to the Zram 2c card. AFAIK, the info is
> the same for all Applied aux memory cards.

I hope so - I'd hate to see what I'm working on not work in a //c.
On a similar note, does the //GS use the same system in emulation
mode ?
 
> First, Applied cards work by using a bank select switch at $c073
> and then using the standard Apple aux bank routines. Basically,
> you select the bank you want then treat it like it's the aux 64k
> bank of ram. Some things to keep in mind, not all cards have the
> full compliment of ram and this should be checked by your program.
> There are multiple interrupt vectors and routines which use aux
> memory should be prepared to disable or deal with them. It is
> recommended that interrupts be disabled in programs not requiring
> their use.

OK - I thought it'd be this simple. I think I'll still need the //e
technical reference to find out more about interrupts etc. in aux.
memory. Oh, do the same trick and limitations apply when using
the auxiliary bank "language card" as they do with aux. bank 0 ?
 
> You select on of 16 valid bank numbers into the bank select
> registers. Data transfers between banks of auxiliary memory must
> done in two stages. First swap from the original page to main ram
> then switch banks and transfer the data to the new bank. Bank zero
> always contains the 80 column display and graphics data for DHR
> and must be active whenever the program updates the display
> screen.

This makes sense, although I had wondered about that. There must be
some pretty cool gate array logic on the AE cards to swap bank 0 back
in when the VOC sweeps through ram...

Thanks for the sample code; very handy. Do you have access to a scanner?
I'd love to get my hands on the docs as my RamWorks III didn't come with
any.
  
> This basic info should help get you started. You may find it
> better to use Prodos and a ramdisk for a more standard method of
> using extra memory.

Nah, too simple; I *want* to try something tricky, just for fun.

I'm familiar with using the RAMRD/RAMWRT switches and the ZP switch,
but I've never tried switching in the language card in auxiliary memory.
For some reason, every article of ever read on the subject of aux.
programming says that it's tricky, and don't bother, but I want to
try it anyway - do you have any material on the subject ?

Cheers,

Matt