Lpc2000

--- In lpc2000@yahoogroups.com, Robert Adsett <subscriptions@...> wrote:
> >I like to know if you think any other ARM licensee is worse.
> 
> Who said anything about ARM licensees?  If you make a broad
statement like 
> the above you have to expect a response in kind.

Perhaps I should have said comparing 4-bit controller to 32-bit ARM is
like comparing apples to oranges :)

> They had to assign the pin somewhere.  No doubt they had their
reasons for 
> the choice they made.  No matter where they put it, it would have
caused 
> someone a problem.

Some solutions cause more problem than others.

> Um how do you lock out the HW in software?  You always have serial ISP 
> available.

ISP relies on the contents of boot sector being kept intact.

It is possible to erase or corrupt the boot sector given this section
of on-chip flash is not protected and does not have SDP or equivalent.

If the (bad) software in the boot block disables JTAG and hangs, then
hardare is useless if we are to accept what we are told.

> >Having to condition analog input in order to use watchdog is a serious
> >design defect.  The fix is simple if it were done in the bootloader.
> >It is the obvious solution.  Saves having endless discussion on how to
> >solve this defect with yet another gate or chip.
> 
> What errata is that?  And how do you fix an failure to condition an
analog 
> input by changing the bootloader?

I think it not in the errata because it is a "feature".

The boot loader sets up external bus interface based on reset
(includign watchdog reset) by reading digital state of ADC input.

This cannot be a sensible thing to do IMO.

> Besides which, surely conditioning an analog input is just basic 
> design?  Is there something special needed?

Conditioning as in making sure it analog inputs are pulled high
whenever the watchdog fires?

How is it possible to do this without ... on yes add an external
watchdog becasue the internal watchdog is useless in this case!

Jaya