Path: utzoo!attcan!uunet!husc6!mailrus!ames!amdahl!nsc!voder!apple!dan
From: dan@Apple.COM (Dan Allen)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Hardware bug in the Ethertalk card?
Message-ID: <12163@apple.Apple.COM>
Date: 14 Jun 88 16:38:23 GMT
References: <410@draken.nada.kth.se>
Reply-To: dan@apple.apple.com.UUCP (Dan Allen)
Organization: Apple Computer Inc, Cupertino, CA
Lines: 18

In article <410@draken.nada.kth.se> ragge@nada.kth.se (Ragnar Sundblad) writes:
>When you write a byte to the buffer memory on the ethertalk card
>both the upper and the lower bytes of that word gets written.
>(Try it with Macsbug!)
>Word and long transfers work well though, so it took a while before
>I understood where something got wrong.
>
>Is this a hardware bug, or am I just stupid?

Make sure that if you want to write just one byte to a memory mapped
address, to use the SB command in MacsBug rather than the SM command.  I
put the SB command in just for memory-mapped IO in the earlier days of
the SCSI Manager because using the SM (Set Memory) command will write a
word or longword, thus causing bizarre things to happen.  You may
already be using the SB (Set Byte) command, in which case ignore this.

Dan Allen
Apple Computer