[Blindapple] running Textalker conditionally
jaybird at bluegrasspals.com
Sat Oct 12 20:50:22 EDT 2013
Textalker itself has to detect where an Echo is located in order to know
how to send control signals to the hardware. If only we had the
Textalker source code, maybe we could figure out how it did this.
BEX also looked for an Echo and ran Textalker only if it found one.
Again, though, I don't know how it did this.
On 10/11/2013 10:43 PM, Kyle wrote:
> Using some clever chr$(7)chr$(7) pairs of beeps for verification, and
> getting a little help from Google Goggles, I have found that
> * PEEK(54) is always 189
> * PEEK(55) is always 158
> * PEEK(56) is always 129
> * PEEK(57) is always 158
> I get these values whether Textalker is running or not. This is using
> the standard Applesoft in ROM via 2 DOS 3.3 compatible disks, one with
> my DOS Bossed Pronto-DOS and the other with Apple's DOS3.3 as found on
> EGAMES.DSK. On the other hand, the Talking Writer test as found on line
> 10000 of its HELLO program appears to work. The value of PEEK(43603) is
> 240 when Textalker is not running, and either 124 if a newer version of
> Textalker i.e. 3.1.2 or 3.1.3 is running or 0 if textalker.blind version
> 1.3 is running. This has been tested both on my DOS Bossed version of
> Pronto-DOS and on Apple DOS3.3 as found on EGAMES.DSK.
> So the only thing left to do is to attempt to iterate through each slot
> 2 through 5, apparently these are the only legal slots for an Echo, and
> to determine whether or not an Echo is connected to any one of these
> either before checking whether or not Textalker is running or just after
> finding out that PEEK(43603) is 240, which is actually probably the best
> time to run such a test, probably from within a GOSUB. The example code
> I found still requires that an already existing binary module be loaded
> into RAM before I can call the subroutine from within Applesoft, so I'm
> essentially back where I started, as I want to do the entire detection
> routine from Applesoft as part of an existing HELLO program. I basically
> just need documentation on how to detect whether a card is plugged into
> a specific slot, and I should be able to take it from there.
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