Re[4]: 6510 CPU extensions

From: groepaz (
Date: 2002-04-22 15:55:18

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    Hello Gideon,
    Monday, April 22, 2002, 3:48:23 PM, you wrote:
    |LA>> That IS really cool, Just the thought of debugging a program *while* it
    |LA>> is running... (and all the spectatular lockups you will accidentally
    GZ> get
    |LA>> when you fudge the wrong instruction!)  ;-)  Those traps and triggers
    |LA>> would be useful too for debugging.
    GZ> |
    GZ> |just as a sidenode.... if you implement that according to the
    GZ> |JEDEC/JTAG standard, you had tons of ready-made applications for
    GZ> |debugging.
    GZ> AFAIK, the JTAG standard only says something about the access to the chip by
    GZ> means of the dedicated JTAG pins. I don't think there is a standard for
    GZ> having access to CPU registers or trace possibilities. Boundary scan
    GZ> structures are captured in the so called .bsd files. Is there a standard
    GZ> JTAG command description file for the internal workings? I have never seen
    GZ> it, but of course that doesn't mean that it doesn't exist.
    uhmz, thats a good question.... i have only worked with those devices
    so far, never implemented one myself..... i am assuming there is some
    kind of standard though, since quite a bunch of applications (eg
    debuggers) support jtag in a non-machine-dependend manner. maybe you
    can gather some info about this by looking at the GDB sources or
    simelar stuff.
    GZ> PS. for the people who are interested: I only implemented two commands so
    GZ> far:
    =>> 'R' <addr hi> <addr low> <length>
    GZ> <=                                   <data0> <data1> ...
    =>> 'W' <addr hi> <addr low> <length> <data0> <data1> ...
    GZ> <= [none]
    =>> others
    GZ> <= '?'
    hehe THAT reminds me of the debugger i have written myself, works very
    much the same :o) have a look at if
    you are curious.... (development is currently freezed but will
    continue when certain stuff in the rr-rom has been fixed)
    Best regards,
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