ragge@nada.kth.se (Ragnar Sundblad) (06/12/88)
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?
dan@Apple.COM (Dan Allen) (06/14/88)
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
ragge@nada.kth.se (Ragnar Sundblad) (06/19/88)
In article <12163@apple.Apple.COM> dan@apple.apple.com.UUCP (Dan Allen) writes: >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 Sorry to say, it does not make any difference. I for now also have found some other strange behaivors of the EtherTalk card memory when using it from the 68020. Where can I find a list of these bugs? (They must be known) Where can I find a list of the rest of the bugs in the card? What different revisions if the EtherTalk card are there now? Which one am I supposed to have? When will people stop making the misstake to let 3COM build their ethernet cards? Tired of debugging someone else's hardware Ragnar Sundblad (ragge@nada.kth.se)