Re: JTAG emulator for MPC8548E (v2)

[Laurent Pinchart <laurent.pinchart@technotrade.biz>]

Hi Eugene,

> > > > The new unit works *mostly* fine. No debugging issue (not that I use
> > > > it that much anyway, now that the board boots Linux), but still a
> > > > flash programming issue. Programming the target parallel NOR flash
> > > > works in slow JTAG mode, but not in faster mode using the internal
> > > > workspace. I reported the problem several months ago and still
> > > > haven't received any solution.
> > >
> > > Most likely problem isn't in BDI but in your setup. Depending on
> > > the particular chip model, to be able use workspace you must have
> > > initialized memory first. In fact, I'm pretty sure you haven't
> > > configured chip correctly to make workspace usable. I've been using
> > > BDI with various PowerPC and MIPS SoCs for many years. It's an
> > > excellent tool, you just have to use it correctly.
> >
> > I wish it was that simple.
>
> Sorry, but it is. It's a low level tool which requires deep knowledge
> of the chip.
>
> >  It is probably a target processor configuration
> > issue, as I can use the workspace if
> >
> > a) the target flash has already been programmed with U-Boot
> > b) the BDI-2000 is misconfigured and fails to stop the target processor
> > at startup.
> >
> > I can thus use the workspace when U-Boot initializes the processor.
>
> Wow, so you knew it wasn't BDI but a configuration problem from the
> start. So it all was just a FUD, how low.

I don't agree with you there. It is a configuration issue related to the BDI. 
For all I know, it could be a bug in the BDI that only occurs when 
initialising given registers in a given sequence. Or it might be an issue 
with the BDI-2000 unit I got, which might have a hardware problem. I blamed 
my configuration file first, but even the tech support people haven't been 
able to locate the issue.

All I know is that U-Boot is able to initialise the processor correctly, but 
the BDI isn't, even when fed with a configuration file that performs the same 
initialisation sequence as U-Boot. There are two possible causes : either I 
got the configuration file wrong and forgot a setting, or the BDI fails to 
perform one of the steps correctly.

> > I had a look at U-Boot code and tried to initialize the processor
> > registers with the same values, without luck. I asked Abatron's French
> > distributor for technical support, and they haven't been able to help me.
> > They made me try lots of different initialization sequences. Several
> > people online sent me their configuration file, and none of them worked
> > for me.
> >
> > So, there must be a configuration problem somewhere, but even Abatron's
> > technical support haven't been able to find it. That's why I complained
> > about their support in my e-mail.
>
> In your original e-mail you made it look like BDI has a bug in it,
> which in fact isn't true. Bad support might be a concern, I agree, but
> this doesn't make a tool bad, IMHO.

I don't know where the bug is, unfortunately. As I stated, the BDI-2000 is a 
nice tool, which helped me a lot. I just wish I hadn't suffered such a bad 
technical support experience. That's probably the French distributor's fault, 
and it seems I have been very unlucky when contacting Abatron directly.

Laurent Pinchart