Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!clyde!uunet!cs.dal.ca!iisat!mackay
From: mackay@iisat.uucp (Daniel MacKay)
Newsgroups: comp.sys.apple
Subject: Need help with P8 GET_TIME, protecting hires screen
Message-ID: <1989Dec5.184730.18783@iisat.uucp>
Date: 5 Dec 89 18:47:30 GMT
Organization: International Information Service, Dart., NS.
Lines: 44

Hello!

I have an old ProDOS 8 AppleSloth program which uses a thermistor
attached to the //c game port to read the temperature and put it up
on a horizontally- scrolling single-hires graph- just like a chart
recorder.  It displays the time and temperature at the bottom of the
mixed display, and each minute scrolls the screen left and plots
a dot where the new temperature is.

When I wrote it a few years ago, I couldn't figure out how to get
AppleSloth to get the time from ProDOS, (who gets it from the Applied
Engineering clock driver) so I just opened and closed a dummy file on the
/RAM volume every few seconds, which caused ProDOS to get the time in the
process, and pop the hours and minutes into $BF93 and $BF92.

When I ran the application the other day, someone was walking on my hires
screen with each open and close of the /RAM file!  I assume it's ProDOS
himself, but I don't know why he does it now when in a previous version  he
didn't- but my ramdisk driver and clock driver have been upgraded, too, so
I don't really know whose fault it is. 

So I need help with one of two things: either instructions on protecting 
my hires screen from ProDOS (I tried setting all the bits in the memory 
bitmap for the hires screen, $BF5C-F, but it didn't help- still got 
walked on), or calling GET_TIME (P8 $82) somehow, which is really a more 
correct solution.

My _BASIC Programming With ProDOS_ book mentions this great vector to
the routine DATETIME, at $BF06, but when called from AppleSloth, (or
the monitor, for that matter) it doesn't do what I expect, namely
drop the time into the appropriate date & time bytes, $BF90-2.  In
fact, it crashes in unusual and unpleasant ways. 

Any help with this hires problem, or time problem, would be appreciated. 
Thanks in advance.   -daniel
--
+---------+				IIS Public Usenet
|    _    |	From the 		Halifax, Nova Scotia
|   (_)===|	disk of ...		mackay@iisat.UUCP
|         |	daniel		...{utai,uunet,watmath}!dalcs!iisat!mackay
+---------+				MACKAY@DALAC.BITNET


--