Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!oakhill!floydg
From: floydg@oakhill.sps.mot.com (Floyd Goodrich-HiEnd Product Eng)
Newsgroups: comp.sys.m68k
Subject: Re: Debugging features on '040?
Message-ID: <1991Feb12.154718.4429@oakhill.sps.mot.com>
Date: 12 Feb 91 15:47:18 GMT
References: <4bh=bBa00YU6MDQUlr@andrew.cmu.edu> <1991Feb10.214320.9974@grebyn.co
Reply-To: floydg@oakhill.UUCP (Floyd Goodrich-HiEnd Applications Eng)
Organization: Motorola Inc., Austin, Texas
Lines: 30

In article <1991Feb10.214320.9974@grebyn.com> ckp@grebyn.com (Checkpoint Technologies) writes:
>In article <4bh=bBa00YU6MDQUlr@andrew.cmu.edu> rh2y+@andrew.cmu.edu (Russell E. Hoffman, II) writes:
>>Just out of sheer curiosity .. What hardware debugging features are implemented
>>on the 68040 ...
>
>If I may add an item to this query, I hear the 68040 chip has an
>on-board debug serial port, and I'm wondering how the chip supports this
>port.  Of course, I have this ideal of something like "console mode" on
>a VAX or Micro-ODT on the LSI-11, where microcode in the chip acts
>rather like primitive on-chip emulator support.  I suspect it's just a
>serial port whose IO control regs are in control-reg space with the
>cache control regs etc., and if so I'll just be a little dissapointed.

	The 68040 has the standard M68000 family debugging hooks: traps,
        breakpoints, tracing, etc.  It also has a number of emulator 
        support pins such as TLNx (Transfer Line # indicate which of the
        4 lines in the cache is being modified), PSTx (Processor Status
        pins), CDIS (cache disable), and MDIS (mmu disable).  It also
        has page programmable User Page Attributes which could be used
        for many things.  The part has all the right hooks in place for
        debugging and emulators to be hooked up.

        The 68040 does not have a serial port as such.  It implements the
        JTAG standard allowing board-level debug and a quick check that
        all the pins are hooked up.  (You can do other things with the
        JTAG features, but I wouldn't classify this as debug support.)

Floyd Goodrich
Motorola Inc., Austin TX
floydg@oakhill.sps.mot.com